Coverage Report

Coverage Report - org.apache.commons.io.FileUtils

Classes in this File
Line Coverage
Branch Coverage
Complexity
FileUtils
88%
602/684
81%
333/410
4.1
 /*
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
  * The ASF licenses this file to You under the Apache License, Version 2.0
  * (the "License"); you may not use this file except in compliance with
  * the License.  You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 package org.apache.commons.io;
 
 import java.io.BufferedOutputStream;
 import java.io.File;
 import java.io.FileFilter;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.OutputStream;
 import java.io.Reader;
 import java.io.UnsupportedEncodingException;
 import java.math.BigInteger;
 import java.net.URL;
 import java.net.URLConnection;
 import java.nio.ByteBuffer;
 import java.nio.channels.FileChannel;
 import java.nio.charset.Charset;
 import java.nio.charset.UnsupportedCharsetException;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Date;
 import java.util.Iterator;
 import java.util.List;
 import java.util.zip.CRC32;
 import java.util.zip.CheckedInputStream;
 import java.util.zip.Checksum;
 
 import org.apache.commons.io.filefilter.DirectoryFileFilter;
 import org.apache.commons.io.filefilter.FalseFileFilter;
 import org.apache.commons.io.filefilter.FileFilterUtils;
 import org.apache.commons.io.filefilter.IOFileFilter;
 import org.apache.commons.io.filefilter.SuffixFileFilter;
 import org.apache.commons.io.filefilter.TrueFileFilter;
 import org.apache.commons.io.output.NullOutputStream;
 
 /**
  * General file manipulation utilities.
  * <p>
  * Facilities are provided in the following areas:
  * <ul>
  * <li>writing to a file
  * <li>reading from a file
  * <li>make a directory including parent directories
  * <li>copying files and directories
  * <li>deleting files and directories
  * <li>converting to and from a URL
  * <li>listing files and directories by filter and extension
  * <li>comparing file content
  * <li>file last changed date
  * <li>calculating a checksum
  * </ul>
  * <p>
  * Origin of code: Excalibur, Alexandria, Commons-Utils
  *
  * @version $Id: FileUtils.java 1480346 2013-05-08 16:45:03Z ggregory $
  */
 public class FileUtils {
 
     /**
      * Instances should NOT be constructed in standard programming.
      */
     public FileUtils() {
         super();
     }
 
     /**
      * The number of bytes in a kilobyte.
      */
     public static final long ONE_KB = 1024;
 
     /**
      * The number of bytes in a kilobyte.
      *
      * @since 2.4
      */
     public static final BigInteger ONE_KB_BI = BigInteger.valueOf(ONE_KB);
 
     /**
      * The number of bytes in a megabyte.
      */
     public static final long ONE_MB = ONE_KB * ONE_KB;
 
     /**
      * The number of bytes in a megabyte.
      *
      * @since 2.4
      */
     public static final BigInteger ONE_MB_BI = ONE_KB_BI.multiply(ONE_KB_BI);
 
     /**
      * The file copy buffer size (30 MB)
      */
     private static final long FILE_COPY_BUFFER_SIZE = ONE_MB * 30;
 
     /**
      * The number of bytes in a gigabyte.
      */
     public static final long ONE_GB = ONE_KB * ONE_MB;
 
     /**
      * The number of bytes in a gigabyte.
      *
      * @since 2.4
      */
     public static final BigInteger ONE_GB_BI = ONE_KB_BI.multiply(ONE_MB_BI);
 
     /**
      * The number of bytes in a terabyte.
      */
     public static final long ONE_TB = ONE_KB * ONE_GB;
 
     /**
      * The number of bytes in a terabyte.
      *
      * @since 2.4
      */
     public static final BigInteger ONE_TB_BI = ONE_KB_BI.multiply(ONE_GB_BI);
 
     /**
      * The number of bytes in a petabyte.
      */
     public static final long ONE_PB = ONE_KB * ONE_TB;
 
     /**
      * The number of bytes in a petabyte.
      *
      * @since 2.4
      */
     public static final BigInteger ONE_PB_BI = ONE_KB_BI.multiply(ONE_TB_BI);
 
     /**
      * The number of bytes in an exabyte.
      */
     public static final long ONE_EB = ONE_KB * ONE_PB;
 
     /**
      * The number of bytes in an exabyte.
      *
      * @since 2.4
      */
     public static final BigInteger ONE_EB_BI = ONE_KB_BI.multiply(ONE_PB_BI);
 
     /**
      * The number of bytes in a zettabyte.
      */
     public static final BigInteger ONE_ZB = BigInteger.valueOf(ONE_KB).multiply(BigInteger.valueOf(ONE_EB));
 
     /**
      * The number of bytes in a yottabyte.
      */
     public static final BigInteger ONE_YB = ONE_KB_BI.multiply(ONE_ZB);
 
     /**
      * An empty array of type <code>File</code>.
      */
     public static final File[] EMPTY_FILE_ARRAY = new File[0];
 
     /**
      * The UTF-8 character set, used to decode octets in URLs.
      */
     private static final Charset UTF8 = Charset.forName("UTF-8");
 
     //-----------------------------------------------------------------------
     /**
      * Construct a file from the set of name elements.
      *
      * @param directory the parent directory
      * @param names the name elements
      * @return the file
      * @since 2.1
      */
     public static File getFile(final File directory, final String... names) {
         if (directory == null) {
             throw new NullPointerException("directorydirectory must not be null");
         }
         if (names == null) {
             throw new NullPointerException("names must not be null");
         }
         File file = directory;
         for (final String name : names) {
             file = new File(file, name);
         }
         return file;
     }
 
     /**
      * Construct a file from the set of name elements.
      *
      * @param names the name elements
      * @return the file
      * @since 2.1
      */
     public static File getFile(final String... names) {
         if (names == null) {
             throw new NullPointerException("names must not be null");
         }
         File file = null;
         for (final String name : names) {
             if (file == null) {
                 file = new File(name);
             } else {
                 file = new File(file, name);
             }
         }
         return file;
     }
 
     /**
      * Returns the path to the system temporary directory.
      *
      * @return the path to the system temporary directory.
      *
      * @since 2.0
      */
     public static String getTempDirectoryPath() {
         return System.getProperty("java.io.tmpdir");
     }
 
     /**
      * Returns a {@link File} representing the system temporary directory.
      *
      * @return the system temporary directory.
      *
      * @since 2.0
      */
     public static File getTempDirectory() {
         return new File(getTempDirectoryPath());
     }
 
     /**
      * Returns the path to the user's home directory.
      *
      * @return the path to the user's home directory.
      *
      * @since 2.0
      */
     public static String getUserDirectoryPath() {
         return System.getProperty("user.home");
     }
 
     /**
      * Returns a {@link File} representing the user's home directory.
      *
      * @return the user's home directory.
      *
      * @since 2.0
      */
     public static File getUserDirectory() {
         return new File(getUserDirectoryPath());
     }
 
     //-----------------------------------------------------------------------
     /**
      * Opens a {@link FileInputStream} for the specified file, providing better
      * error messages than simply calling <code>new FileInputStream(file)</code>.
      * <p>
      * At the end of the method either the stream will be successfully opened,
      * or an exception will have been thrown.
      * <p>
      * An exception is thrown if the file does not exist.
      * An exception is thrown if the file object exists but is a directory.
      * An exception is thrown if the file exists but cannot be read.
      *
      * @param file  the file to open for input, must not be {@code null}
      * @return a new {@link FileInputStream} for the specified file
      * @throws FileNotFoundException if the file does not exist
      * @throws IOException if the file object is a directory
      * @throws IOException if the file cannot be read
      * @since 1.3
      */
     public static FileInputStream openInputStream(final File file) throws IOException {
         if (file.exists()) {
             if (file.isDirectory()) {
                 throw new IOException("File '" + file + "' exists but is a directory");
             }
             if (file.canRead() == false) {
                 throw new IOException("File '" + file + "' cannot be read");
             }
         } else {
             throw new FileNotFoundException("File '" + file + "' does not exist");
         }
         return new FileInputStream(file);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Opens a {@link FileOutputStream} for the specified file, checking and
      * creating the parent directory if it does not exist.
      * <p>
      * At the end of the method either the stream will be successfully opened,
      * or an exception will have been thrown.
      * <p>
      * The parent directory will be created if it does not exist.
      * The file will be created if it does not exist.
      * An exception is thrown if the file object exists but is a directory.
      * An exception is thrown if the file exists but cannot be written to.
      * An exception is thrown if the parent directory cannot be created.
      *
      * @param file  the file to open for output, must not be {@code null}
      * @return a new {@link FileOutputStream} for the specified file
      * @throws IOException if the file object is a directory
      * @throws IOException if the file cannot be written to
      * @throws IOException if a parent directory needs creating but that fails
      * @since 1.3
      */
     public static FileOutputStream openOutputStream(final File file) throws IOException {
         return openOutputStream(file, false);
     }
 
     /**
      * Opens a {@link FileOutputStream} for the specified file, checking and
      * creating the parent directory if it does not exist.
      * <p>
      * At the end of the method either the stream will be successfully opened,
      * or an exception will have been thrown.
      * <p>
      * The parent directory will be created if it does not exist.
      * The file will be created if it does not exist.
      * An exception is thrown if the file object exists but is a directory.
      * An exception is thrown if the file exists but cannot be written to.
      * An exception is thrown if the parent directory cannot be created.
      *
      * @param file  the file to open for output, must not be {@code null}
      * @param append if {@code true}, then bytes will be added to the
      * end of the file rather than overwriting
      * @return a new {@link FileOutputStream} for the specified file
      * @throws IOException if the file object is a directory
      * @throws IOException if the file cannot be written to
      * @throws IOException if a parent directory needs creating but that fails
      * @since 2.1
      */
     public static FileOutputStream openOutputStream(final File file, final boolean append) throws IOException {
         if (file.exists()) {
             if (file.isDirectory()) {
                 throw new IOException("File '" + file + "' exists but is a directory");
             }
             if (file.canWrite() == false) {
                 throw new IOException("File '" + file + "' cannot be written to");
             }
         } else {
             final File parent = file.getParentFile();
             if (parent != null) {
                 if (!parent.mkdirs() && !parent.isDirectory()) {
                     throw new IOException("Directory '" + parent + "' could not be created");
                 }
             }
         }
         return new FileOutputStream(file, append);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Returns a human-readable version of the file size, where the input represents a specific number of bytes.
      * <p>
      * If the size is over 1GB, the size is returned as the number of whole GB, i.e. the size is rounded down to the
      * nearest GB boundary.
      * </p>
      * <p>
      * Similarly for the 1MB and 1KB boundaries.
      * </p>
      *
      * @param size
      *            the number of bytes
      * @return a human-readable display value (includes units - EB, PB, TB, GB, MB, KB or bytes)
      * @see <a href="https://issues.apache.org/jira/browse/IO-226">IO-226 - should the rounding be changed?</a>
      * @since 2.4
      */
     // See https://issues.apache.org/jira/browse/IO-226 - should the rounding be changed?
     public static String byteCountToDisplaySize(final BigInteger size) {
         String displaySize;
 
         if (size.divide(ONE_EB_BI).compareTo(BigInteger.ZERO) > 0) {
             displaySize = String.valueOf(size.divide(ONE_EB_BI)) + " EB";
         } else if (size.divide(ONE_PB_BI).compareTo(BigInteger.ZERO) > 0) {
             displaySize = String.valueOf(size.divide(ONE_PB_BI)) + " PB";
         } else if (size.divide(ONE_TB_BI).compareTo(BigInteger.ZERO) > 0) {
             displaySize = String.valueOf(size.divide(ONE_TB_BI)) + " TB";
         } else if (size.divide(ONE_GB_BI).compareTo(BigInteger.ZERO) > 0) {
             displaySize = String.valueOf(size.divide(ONE_GB_BI)) + " GB";
         } else if (size.divide(ONE_MB_BI).compareTo(BigInteger.ZERO) > 0) {
             displaySize = String.valueOf(size.divide(ONE_MB_BI)) + " MB";
         } else if (size.divide(ONE_KB_BI).compareTo(BigInteger.ZERO) > 0) {
             displaySize = String.valueOf(size.divide(ONE_KB_BI)) + " KB";
         } else {
             displaySize = String.valueOf(size) + " bytes";
         }
         return displaySize;
     }
 
     /**
      * Returns a human-readable version of the file size, where the input represents a specific number of bytes.
      * <p>
      * If the size is over 1GB, the size is returned as the number of whole GB, i.e. the size is rounded down to the
      * nearest GB boundary.
      * </p>
      * <p>
      * Similarly for the 1MB and 1KB boundaries.
      * </p>
      *
      * @param size
      *            the number of bytes
      * @return a human-readable display value (includes units - EB, PB, TB, GB, MB, KB or bytes)
      * @see <a href="https://issues.apache.org/jira/browse/IO-226">IO-226 - should the rounding be changed?</a>
      */
     // See https://issues.apache.org/jira/browse/IO-226 - should the rounding be changed?
     public static String byteCountToDisplaySize(final long size) {
         return byteCountToDisplaySize(BigInteger.valueOf(size));
     }
 
     //-----------------------------------------------------------------------
     /**
      * Implements the same behaviour as the "touch" utility on Unix. It creates
      * a new file with size 0 or, if the file exists already, it is opened and
      * closed without modifying it, but updating the file date and time.
      * <p>
      * NOTE: As from v1.3, this method throws an IOException if the last
      * modified date of the file cannot be set. Also, as from v1.3 this method
      * creates parent directories if they do not exist.
      *
      * @param file  the File to touch
      * @throws IOException If an I/O problem occurs
      */
     public static void touch(final File file) throws IOException {
         if (!file.exists()) {
             final OutputStream out = openOutputStream(file);
             IOUtils.closeQuietly(out);
         }
         final boolean success = file.setLastModified(System.currentTimeMillis());
         if (!success) {
             throw new IOException("Unable to set the last modification time for " + file);
         }
     }
 
     //-----------------------------------------------------------------------
     /**
      * Converts a Collection containing java.io.File instanced into array
      * representation. This is to account for the difference between
      * File.listFiles() and FileUtils.listFiles().
      *
      * @param files  a Collection containing java.io.File instances
      * @return an array of java.io.File
      */
     public static File[] convertFileCollectionToFileArray(final Collection<File> files) {
          return files.toArray(new File[files.size()]);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Finds files within a given directory (and optionally its
      * subdirectories). All files found are filtered by an IOFileFilter.
      *
      * @param files the collection of files found.
      * @param directory the directory to search in.
      * @param filter the filter to apply to files and directories.
      * @param includeSubDirectories indicates if will include the subdirectories themselves
      */
     private static void innerListFiles(final Collection<File> files, final File directory,
             final IOFileFilter filter, final boolean includeSubDirectories) {
         final File[] found = directory.listFiles((FileFilter) filter);
 
         if (found != null) {
             for (final File file : found) {
                 if (file.isDirectory()) {
                     if (includeSubDirectories) {
                         files.add(file);
                     }
                     innerListFiles(files, file, filter, includeSubDirectories);
                 } else {
                     files.add(file);
                 }
             }
         }
     }
 
     /**
      * Finds files within a given directory (and optionally its
      * subdirectories). All files found are filtered by an IOFileFilter.
      * <p>
      * If your search should recurse into subdirectories you can pass in
      * an IOFileFilter for directories. You don't need to bind a
      * DirectoryFileFilter (via logical AND) to this filter. This method does
      * that for you.
      * <p>
      * An example: If you want to search through all directories called
      * "temp" you pass in <code>FileFilterUtils.NameFileFilter("temp")</code>
      * <p>
      * Another common usage of this method is find files in a directory
      * tree but ignoring the directories generated CVS. You can simply pass
      * in <code>FileFilterUtils.makeCVSAware(null)</code>.
      *
      * @param directory  the directory to search in
      * @param fileFilter  filter to apply when finding files.
      * @param dirFilter  optional filter to apply when finding subdirectories.
      * If this parameter is {@code null}, subdirectories will not be included in the
      * search. Use TrueFileFilter.INSTANCE to match all directories.
      * @return an collection of java.io.File with the matching files
      * @see org.apache.commons.io.filefilter.FileFilterUtils
      * @see org.apache.commons.io.filefilter.NameFileFilter
      */
     public static Collection<File> listFiles(
             final File directory, final IOFileFilter fileFilter, final IOFileFilter dirFilter) {
         validateListFilesParameters(directory, fileFilter);
 
         final IOFileFilter effFileFilter = setUpEffectiveFileFilter(fileFilter);
         final IOFileFilter effDirFilter = setUpEffectiveDirFilter(dirFilter);
 
         //Find files
         final Collection<File> files = new java.util.LinkedList<File>();
         innerListFiles(files, directory,
             FileFilterUtils.or(effFileFilter, effDirFilter), false);
         return files;
     }
 
     /**
      * Validates the given arguments.
      * <ul>
      * <li>Throws {@link IllegalArgumentException} if {@code directory} is not a directory</li>
      * <li>Throws {@link NullPointerException} if {@code fileFilter} is null</li>
      * </ul>
      *
      * @param directory The File to test
      * @param fileFilter The IOFileFilter to test
      */
     private static void validateListFilesParameters(final File directory, final IOFileFilter fileFilter) {
         if (!directory.isDirectory()) {
             throw new IllegalArgumentException("Parameter 'directory' is not a directory: " + directory);
         }
         if (fileFilter == null) {
             throw new NullPointerException("Parameter 'fileFilter' is null");
         }
     }
 
     /**
      * Returns a filter that accepts files in addition to the {@link File} objects accepted by the given filter.
      *
      * @param fileFilter a base filter to add to
      * @return a filter that accepts files
      */
     private static IOFileFilter setUpEffectiveFileFilter(final IOFileFilter fileFilter) {
         return FileFilterUtils.and(fileFilter, FileFilterUtils.notFileFilter(DirectoryFileFilter.INSTANCE));
     }
 
     /**
      * Returns a filter that accepts directories in addition to the {@link File} objects accepted by the given filter.
      *
      * @param dirFilter a base filter to add to
      * @return a filter that accepts directories
      */
     private static IOFileFilter setUpEffectiveDirFilter(final IOFileFilter dirFilter) {
         return dirFilter == null ? FalseFileFilter.INSTANCE : FileFilterUtils.and(dirFilter,
                 DirectoryFileFilter.INSTANCE);
     }
 
     /**
      * Finds files within a given directory (and optionally its
      * subdirectories). All files found are filtered by an IOFileFilter.
      * <p>
      * The resulting collection includes the starting directory and
      * any subdirectories that match the directory filter.
      * <p>
      * @see org.apache.commons.io.FileUtils#listFiles
      *
      * @param directory  the directory to search in
      * @param fileFilter  filter to apply when finding files.
      * @param dirFilter  optional filter to apply when finding subdirectories.
      * If this parameter is {@code null}, subdirectories will not be included in the
      * search. Use TrueFileFilter.INSTANCE to match all directories.
      * @return an collection of java.io.File with the matching files
      * @see org.apache.commons.io.filefilter.FileFilterUtils
      * @see org.apache.commons.io.filefilter.NameFileFilter
      * @since 2.2
      */
     public static Collection<File> listFilesAndDirs(
             final File directory, final IOFileFilter fileFilter, final IOFileFilter dirFilter) {
         validateListFilesParameters(directory, fileFilter);
 
         final IOFileFilter effFileFilter = setUpEffectiveFileFilter(fileFilter);
         final IOFileFilter effDirFilter = setUpEffectiveDirFilter(dirFilter);
 
         //Find files
         final Collection<File> files = new java.util.LinkedList<File>();
         if (directory.isDirectory()) {
             files.add(directory);
         }
         innerListFiles(files, directory,
             FileFilterUtils.or(effFileFilter, effDirFilter), true);
         return files;
     }
 
     /**
      * Allows iteration over the files in given directory (and optionally
      * its subdirectories).
      * <p>
      * All files found are filtered by an IOFileFilter. This method is
      * based on {@link #listFiles(File, IOFileFilter, IOFileFilter)},
      * which supports Iterable ('foreach' loop).
      * <p>
      * @param directory  the directory to search in
      * @param fileFilter  filter to apply when finding files.
      * @param dirFilter  optional filter to apply when finding subdirectories.
      * If this parameter is {@code null}, subdirectories will not be included in the
      * search. Use TrueFileFilter.INSTANCE to match all directories.
      * @return an iterator of java.io.File for the matching files
      * @see org.apache.commons.io.filefilter.FileFilterUtils
      * @see org.apache.commons.io.filefilter.NameFileFilter
      * @since 1.2
      */
     public static Iterator<File> iterateFiles(
             final File directory, final IOFileFilter fileFilter, final IOFileFilter dirFilter) {
         return listFiles(directory, fileFilter, dirFilter).iterator();
     }
 
     /**
      * Allows iteration over the files in given directory (and optionally
      * its subdirectories).
      * <p>
      * All files found are filtered by an IOFileFilter. This method is
      * based on {@link #listFilesAndDirs(File, IOFileFilter, IOFileFilter)},
      * which supports Iterable ('foreach' loop).
      * <p>
      * The resulting iterator includes the subdirectories themselves.
      *
      * @param directory  the directory to search in
      * @param fileFilter  filter to apply when finding files.
      * @param dirFilter  optional filter to apply when finding subdirectories.
      * If this parameter is {@code null}, subdirectories will not be included in the
      * search. Use TrueFileFilter.INSTANCE to match all directories.
      * @return an iterator of java.io.File for the matching files
      * @see org.apache.commons.io.filefilter.FileFilterUtils
      * @see org.apache.commons.io.filefilter.NameFileFilter
      * @since 2.2
      */
     public static Iterator<File> iterateFilesAndDirs(final File directory, final IOFileFilter fileFilter, final IOFileFilter dirFilter) {
         return listFilesAndDirs(directory, fileFilter, dirFilter).iterator();
     }
 
     //-----------------------------------------------------------------------
     /**
      * Converts an array of file extensions to suffixes for use
      * with IOFileFilters.
      *
      * @param extensions  an array of extensions. Format: {"java", "xml"}
      * @return an array of suffixes. Format: {".java", ".xml"}
      */
     private static String[] toSuffixes(final String[] extensions) {
         final String[] suffixes = new String[extensions.length];
         for (int i = 0; i < extensions.length; i++) {
             suffixes[i] = "." + extensions[i];
         }
         return suffixes;
     }
 
 
     /**
      * Finds files within a given directory (and optionally its subdirectories)
      * which match an array of extensions.
      *
      * @param directory  the directory to search in
      * @param extensions  an array of extensions, ex. {"java","xml"}. If this
      * parameter is {@code null}, all files are returned.
      * @param recursive  if true all subdirectories are searched as well
      * @return an collection of java.io.File with the matching files
      */
     public static Collection<File> listFiles(
             final File directory, final String[] extensions, final boolean recursive) {
         IOFileFilter filter;
         if (extensions == null) {
             filter = TrueFileFilter.INSTANCE;
         } else {
             final String[] suffixes = toSuffixes(extensions);
             filter = new SuffixFileFilter(suffixes);
         }
         return listFiles(directory, filter,
             recursive ? TrueFileFilter.INSTANCE : FalseFileFilter.INSTANCE);
     }
 
     /**
      * Allows iteration over the files in a given directory (and optionally
      * its subdirectories) which match an array of extensions. This method
      * is based on {@link #listFiles(File, String[], boolean)},
      * which supports Iterable ('foreach' loop).
      *
      * @param directory  the directory to search in
      * @param extensions  an array of extensions, ex. {"java","xml"}. If this
      * parameter is {@code null}, all files are returned.
      * @param recursive  if true all subdirectories are searched as well
      * @return an iterator of java.io.File with the matching files
      * @since 1.2
      */
     public static Iterator<File> iterateFiles(
             final File directory, final String[] extensions, final boolean recursive) {
         return listFiles(directory, extensions, recursive).iterator();
     }
 
     //-----------------------------------------------------------------------
     /**
      * Compares the contents of two files to determine if they are equal or not.
      * <p>
      * This method checks to see if the two files are different lengths
      * or if they point to the same file, before resorting to byte-by-byte
      * comparison of the contents.
      * <p>
      * Code origin: Avalon
      *
      * @param file1  the first file
      * @param file2  the second file
      * @return true if the content of the files are equal or they both don't
      * exist, false otherwise
      * @throws IOException in case of an I/O error
      */
     public static boolean contentEquals(final File file1, final File file2) throws IOException {
         final boolean file1Exists = file1.exists();
         if (file1Exists != file2.exists()) {
             return false;
         }
 
         if (!file1Exists) {
             // two not existing files are equal
             return true;
         }
 
         if (file1.isDirectory() || file2.isDirectory()) {
             // don't want to compare directory contents
             throw new IOException("Can't compare directories, only files");
         }
 
         if (file1.length() != file2.length()) {
             // lengths differ, cannot be equal
             return false;
         }
 
         if (file1.getCanonicalFile().equals(file2.getCanonicalFile())) {
             // same file
             return true;
         }
 
         InputStream input1 = null;
         InputStream input2 = null;
         try {
             input1 = new FileInputStream(file1);
             input2 = new FileInputStream(file2);
             return IOUtils.contentEquals(input1, input2);
 
         } finally {
             IOUtils.closeQuietly(input1);
             IOUtils.closeQuietly(input2);
         }
     }
 
     //-----------------------------------------------------------------------
     /**
      * Compares the contents of two files to determine if they are equal or not.
      * <p>
      * This method checks to see if the two files point to the same file,
      * before resorting to line-by-line comparison of the contents.
      * <p>
      *
      * @param file1  the first file
      * @param file2  the second file
      * @param charsetName the character encoding to be used.
      *        May be null, in which case the platform default is used
      * @return true if the content of the files are equal or neither exists,
      *         false otherwise
      * @throws IOException in case of an I/O error
      * @since 2.2
      * @see IOUtils#contentEqualsIgnoreEOL(Reader, Reader)
      */
     public static boolean contentEqualsIgnoreEOL(final File file1, final File file2, final String charsetName) throws IOException {
         final boolean file1Exists = file1.exists();
         if (file1Exists != file2.exists()) {
             return false;
         }
 
         if (!file1Exists) {
             // two not existing files are equal
             return true;
         }
 
         if (file1.isDirectory() || file2.isDirectory()) {
             // don't want to compare directory contents
             throw new IOException("Can't compare directories, only files");
         }
 
         if (file1.getCanonicalFile().equals(file2.getCanonicalFile())) {
             // same file
             return true;
         }
 
         Reader input1 = null;
         Reader input2 = null;
         try {
             if (charsetName == null) {
                 // N.B. make explicit the use of the default charset
                 input1 = new InputStreamReader(new FileInputStream(file1), Charset.defaultCharset());
                 input2 = new InputStreamReader(new FileInputStream(file2), Charset.defaultCharset());
             } else {
                 input1 = new InputStreamReader(new FileInputStream(file1), charsetName);
                 input2 = new InputStreamReader(new FileInputStream(file2), charsetName);
             }
             return IOUtils.contentEqualsIgnoreEOL(input1, input2);
 
         } finally {
             IOUtils.closeQuietly(input1);
             IOUtils.closeQuietly(input2);
         }
     }
 
     //-----------------------------------------------------------------------
     /**
      * Convert from a <code>URL</code> to a <code>File</code>.
      * <p>
      * From version 1.1 this method will decode the URL.
      * Syntax such as <code>file:///my%20docs/file.txt</code> will be
      * correctly decoded to <code>/my docs/file.txt</code>. Starting with version
      * 1.5, this method uses UTF-8 to decode percent-encoded octets to characters.
      * Additionally, malformed percent-encoded octets are handled leniently by
      * passing them through literally.
      *
      * @param url  the file URL to convert, {@code null} returns {@code null}
      * @return the equivalent <code>File</code> object, or {@code null}
      *  if the URL's protocol is not <code>file</code>
      */
     public static File toFile(final URL url) {
         if (url == null || !"file".equalsIgnoreCase(url.getProtocol())) {
             return null;
         } else {
             String filename = url.getFile().replace('/', File.separatorChar);
             filename = decodeUrl(filename);
             return new File(filename);
         }
     }
 
     /**
      * Decodes the specified URL as per RFC 3986, i.e. transforms
      * percent-encoded octets to characters by decoding with the UTF-8 character
      * set. This function is primarily intended for usage with
      * {@link java.net.URL} which unfortunately does not enforce proper URLs. As
      * such, this method will leniently accept invalid characters or malformed
      * percent-encoded octets and simply pass them literally through to the
      * result string. Except for rare edge cases, this will make unencoded URLs
      * pass through unaltered.
      *
      * @param url  The URL to decode, may be {@code null}.
      * @return The decoded URL or {@code null} if the input was
      *         {@code null}.
      */
     static String decodeUrl(final String url) {
         String decoded = url;
         if (url != null && url.indexOf('%') >= 0) {
             final int n = url.length();
             final StringBuffer buffer = new StringBuffer();
             final ByteBuffer bytes = ByteBuffer.allocate(n);
             for (int i = 0; i < n;) {
                 if (url.charAt(i) == '%') {
                     try {
                         do {
                             final byte octet = (byte) Integer.parseInt(url.substring(i + 1, i + 3), 16);
                             bytes.put(octet);
                             i += 3;
                         } while (i < n && url.charAt(i) == '%');
                         continue;
                     } catch (final RuntimeException e) {
                         // malformed percent-encoded octet, fall through and
                         // append characters literally
                     } finally {
                         if (bytes.position() > 0) {
                             bytes.flip();
                             buffer.append(UTF8.decode(bytes).toString());
                             bytes.clear();
                         }
                     }
                 }
                 buffer.append(url.charAt(i++));
             }
             decoded = buffer.toString();
         }
         return decoded;
     }
 
     /**
      * Converts each of an array of <code>URL</code> to a <code>File</code>.
      * <p>
      * Returns an array of the same size as the input.
      * If the input is {@code null}, an empty array is returned.
      * If the input contains {@code null}, the output array contains {@code null} at the same
      * index.
      * <p>
      * This method will decode the URL.
      * Syntax such as <code>file:///my%20docs/file.txt</code> will be
      * correctly decoded to <code>/my docs/file.txt</code>.
      *
      * @param urls  the file URLs to convert, {@code null} returns empty array
      * @return a non-{@code null} array of Files matching the input, with a {@code null} item
      *  if there was a {@code null} at that index in the input array
      * @throws IllegalArgumentException if any file is not a URL file
      * @throws IllegalArgumentException if any file is incorrectly encoded
      * @since 1.1
      */
     public static File[] toFiles(final URL[] urls) {
         if (urls == null || urls.length == 0) {
             return EMPTY_FILE_ARRAY;
         }
         final File[] files = new File[urls.length];
         for (int i = 0; i < urls.length; i++) {
             final URL url = urls[i];
             if (url != null) {
                 if (url.getProtocol().equals("file") == false) {
                     throw new IllegalArgumentException(
                             "URL could not be converted to a File: " + url);
                 }
                 files[i] = toFile(url);
             }
         }
         return files;
     }
 
     /**
      * Converts each of an array of <code>File</code> to a <code>URL</code>.
      * <p>
      * Returns an array of the same size as the input.
      *
      * @param files  the files to convert, must not be {@code null}
      * @return an array of URLs matching the input
      * @throws IOException if a file cannot be converted
      * @throws NullPointerException if the parameter is null
      */
     public static URL[] toURLs(final File[] files) throws IOException {
         final URL[] urls = new URL[files.length];
 
         for (int i = 0; i < urls.length; i++) {
             urls[i] = files[i].toURI().toURL();
         }
 
         return urls;
     }
 
     //-----------------------------------------------------------------------
     /**
      * Copies a file to a directory preserving the file date.
      * <p>
      * This method copies the contents of the specified source file
      * to a file of the same name in the specified destination directory.
      * The destination directory is created if it does not exist.
      * If the destination file exists, then this method will overwrite it.
      * <p>
      * <strong>Note:</strong> This method tries to preserve the file's last
      * modified date/times using {@link File#setLastModified(long)}, however
      * it is not guaranteed that the operation will succeed.
      * If the modification operation fails, no indication is provided.
      *
      * @param srcFile  an existing file to copy, must not be {@code null}
      * @param destDir  the directory to place the copy in, must not be {@code null}
      *
      * @throws NullPointerException if source or destination is null
      * @throws IOException if source or destination is invalid
      * @throws IOException if an IO error occurs during copying
      * @see #copyFile(File, File, boolean)
      */
     public static void copyFileToDirectory(final File srcFile, final File destDir) throws IOException {
         copyFileToDirectory(srcFile, destDir, true);
     }
 
     /**
      * Copies a file to a directory optionally preserving the file date.
      * <p>
      * This method copies the contents of the specified source file
      * to a file of the same name in the specified destination directory.
      * The destination directory is created if it does not exist.
      * If the destination file exists, then this method will overwrite it.
      * <p>
      * <strong>Note:</strong> Setting <code>preserveFileDate</code> to
      * {@code true} tries to preserve the file's last modified
      * date/times using {@link File#setLastModified(long)}, however it is
      * not guaranteed that the operation will succeed.
      * If the modification operation fails, no indication is provided.
      *
      * @param srcFile  an existing file to copy, must not be {@code null}
      * @param destDir  the directory to place the copy in, must not be {@code null}
      * @param preserveFileDate  true if the file date of the copy
      *  should be the same as the original
      *
      * @throws NullPointerException if source or destination is {@code null}
      * @throws IOException if source or destination is invalid
      * @throws IOException if an IO error occurs during copying
      * @see #copyFile(File, File, boolean)
      * @since 1.3
      */
     public static void copyFileToDirectory(final File srcFile, final File destDir, final boolean preserveFileDate) throws IOException {
         if (destDir == null) {
             throw new NullPointerException("Destination must not be null");
         }
         if (destDir.exists() && destDir.isDirectory() == false) {
             throw new IllegalArgumentException("Destination '" + destDir + "' is not a directory");
         }
         final File destFile = new File(destDir, srcFile.getName());
         copyFile(srcFile, destFile, preserveFileDate);
     }
 
     /**
      * Copies a file to a new location preserving the file date.
      * <p>
      * This method copies the contents of the specified source file to the
      * specified destination file. The directory holding the destination file is
      * created if it does not exist. If the destination file exists, then this
      * method will overwrite it.
      * <p>
      * <strong>Note:</strong> This method tries to preserve the file's last
      * modified date/times using {@link File#setLastModified(long)}, however
      * it is not guaranteed that the operation will succeed.
      * If the modification operation fails, no indication is provided.
      *
      * @param srcFile  an existing file to copy, must not be {@code null}
      * @param destFile  the new file, must not be {@code null}
      *
      * @throws NullPointerException if source or destination is {@code null}
      * @throws IOException if source or destination is invalid
      * @throws IOException if an IO error occurs during copying
      * @see #copyFileToDirectory(File, File)
      */
     public static void copyFile(final File srcFile, final File destFile) throws IOException {
         copyFile(srcFile, destFile, true);
     }
 
     /**
      * Copies a file to a new location.
      * <p>
      * This method copies the contents of the specified source file
      * to the specified destination file.
      * The directory holding the destination file is created if it does not exist.
      * If the destination file exists, then this method will overwrite it.
      * <p>
      * <strong>Note:</strong> Setting <code>preserveFileDate</code> to
      * {@code true} tries to preserve the file's last modified
      * date/times using {@link File#setLastModified(long)}, however it is
      * not guaranteed that the operation will succeed.
      * If the modification operation fails, no indication is provided.
      *
      * @param srcFile  an existing file to copy, must not be {@code null}
      * @param destFile  the new file, must not be {@code null}
      * @param preserveFileDate  true if the file date of the copy
      *  should be the same as the original
      *
      * @throws NullPointerException if source or destination is {@code null}
      * @throws IOException if source or destination is invalid
      * @throws IOException if an IO error occurs during copying
      * @see #copyFileToDirectory(File, File, boolean)
      */
     public static void copyFile(final File srcFile, final File destFile,
             final boolean preserveFileDate) throws IOException {
         if (srcFile == null) {
             throw new NullPointerException("Source must not be null");
         }
         if (destFile == null) {
             throw new NullPointerException("Destination must not be null");
         }
         if (srcFile.exists() == false) {
             throw new FileNotFoundException("Source '" + srcFile + "' does not exist");
         }
         if (srcFile.isDirectory()) {
             throw new IOException("Source '" + srcFile + "' exists but is a directory");
         }
         if (srcFile.getCanonicalPath().equals(destFile.getCanonicalPath())) {
             throw new IOException("Source '" + srcFile + "' and destination '" + destFile + "' are the same");
         }
         final File parentFile = destFile.getParentFile();
         if (parentFile != null) {
             if (!parentFile.mkdirs() && !parentFile.isDirectory()) {
                 throw new IOException("Destination '" + parentFile + "' directory cannot be created");
             }
         }
         if (destFile.exists() && destFile.canWrite() == false) {
             throw new IOException("Destination '" + destFile + "' exists but is read-only");
         }
         doCopyFile(srcFile, destFile, preserveFileDate);
     }
 
     /**
      * Copy bytes from a <code>File</code> to an <code>OutputStream</code>.
      * <p>
      * This method buffers the input internally, so there is no need to use a <code>BufferedInputStream</code>.
      * </p>
      *
      * @param input
      *            the <code>File</code> to read from
      * @param output
      *            the <code>OutputStream</code> to write to
      * @return the number of bytes copied
      * @throws NullPointerException
      *             if the input or output is null
      * @throws IOException
      *             if an I/O error occurs
      * @since 2.1
      */
     public static long copyFile(final File input, final OutputStream output) throws IOException {
         final FileInputStream fis = new FileInputStream(input);
         try {
             return IOUtils.copyLarge(fis, output);
         } finally {
             fis.close();
         }
     }
 
     /**
      * Internal copy file method.
      *
      * @param srcFile  the validated source file, must not be {@code null}
      * @param destFile  the validated destination file, must not be {@code null}
      * @param preserveFileDate  whether to preserve the file date
      * @throws IOException if an error occurs
      */
     private static void doCopyFile(final File srcFile, final File destFile, final boolean preserveFileDate) throws IOException {
         if (destFile.exists() && destFile.isDirectory()) {
             throw new IOException("Destination '" + destFile + "' exists but is a directory");
         }
 
         FileInputStream fis = null;
         FileOutputStream fos = null;
         FileChannel input = null;
         FileChannel output = null;
         try {
             fis = new FileInputStream(srcFile);
             fos = new FileOutputStream(destFile);
             input  = fis.getChannel();
             output = fos.getChannel();
             final long size = input.size();
             long pos = 0;
             long count = 0;
             while (pos < size) {
                 count = size - pos > FILE_COPY_BUFFER_SIZE ? FILE_COPY_BUFFER_SIZE : size - pos;
                 pos += output.transferFrom(input, pos, count);
             }
         } finally {
             IOUtils.closeQuietly(output);
             IOUtils.closeQuietly(fos);
             IOUtils.closeQuietly(input);
             IOUtils.closeQuietly(fis);
         }
 
         if (srcFile.length() != destFile.length()) {
             throw new IOException("Failed to copy full contents from '" +
                     srcFile + "' to '" + destFile + "'");
         }
         if (preserveFileDate) {
             destFile.setLastModified(srcFile.lastModified());
         }
     }
 
     //-----------------------------------------------------------------------
     /**
      * Copies a directory to within another directory preserving the file dates.
      * <p>
      * This method copies the source directory and all its contents to a
      * directory of the same name in the specified destination directory.
      * <p>
      * The destination directory is created if it does not exist.
      * If the destination directory did exist, then this method merges
      * the source with the destination, with the source taking precedence.
      * <p>
      * <strong>Note:</strong> This method tries to preserve the files' last
      * modified date/times using {@link File#setLastModified(long)}, however
      * it is not guaranteed that those operations will succeed.
      * If the modification operation fails, no indication is provided.
      *
      * @param srcDir  an existing directory to copy, must not be {@code null}
      * @param destDir  the directory to place the copy in, must not be {@code null}
      *
      * @throws NullPointerException if source or destination is {@code null}
      * @throws IOException if source or destination is invalid
      * @throws IOException if an IO error occurs during copying
      * @since 1.2
      */
     public static void copyDirectoryToDirectory(final File srcDir, final File destDir) throws IOException {
         if (srcDir == null) {
             throw new NullPointerException("Source must not be null");
         }
         if (srcDir.exists() && srcDir.isDirectory() == false) {
             throw new IllegalArgumentException("Source '" + destDir + "' is not a directory");
         }
         if (destDir == null) {
             throw new NullPointerException("Destination must not be null");
         }
         if (destDir.exists() && destDir.isDirectory() == false) {
             throw new IllegalArgumentException("Destination '" + destDir + "' is not a directory");
         }
         copyDirectory(srcDir, new File(destDir, srcDir.getName()), true);
     }
 
     /**
      * Copies a whole directory to a new location preserving the file dates.
      * <p>
      * This method copies the specified directory and all its child
      * directories and files to the specified destination.
      * The destination is the new location and name of the directory.
      * <p>
      * The destination directory is created if it does not exist.
      * If the destination directory did exist, then this method merges
      * the source with the destination, with the source taking precedence.
      * <p>
      * <strong>Note:</strong> This method tries to preserve the files' last
      * modified date/times using {@link File#setLastModified(long)}, however
      * it is not guaranteed that those operations will succeed.
      * If the modification operation fails, no indication is provided.
      *
      * @param srcDir  an existing directory to copy, must not be {@code null}
      * @param destDir  the new directory, must not be {@code null}
      *
      * @throws NullPointerException if source or destination is {@code null}
      * @throws IOException if source or destination is invalid
      * @throws IOException if an IO error occurs during copying
      * @since 1.1
      */
     public static void copyDirectory(final File srcDir, final File destDir) throws IOException {
         copyDirectory(srcDir, destDir, true);
     }
 
     /**
      * Copies a whole directory to a new location.
      * <p>
      * This method copies the contents of the specified source directory
      * to within the specified destination directory.
      * <p>
      * The destination directory is created if it does not exist.
      * If the destination directory did exist, then this method merges
      * the source with the destination, with the source taking precedence.
      * <p>
      * <strong>Note:</strong> Setting <code>preserveFileDate</code> to
      * {@code true} tries to preserve the files' last modified
      * date/times using {@link File#setLastModified(long)}, however it is
      * not guaranteed that those operations will succeed.
      * If the modification operation fails, no indication is provided.
      *
      * @param srcDir  an existing directory to copy, must not be {@code null}
      * @param destDir  the new directory, must not be {@code null}
      * @param preserveFileDate  true if the file date of the copy
      *  should be the same as the original
      *
      * @throws NullPointerException if source or destination is {@code null}
      * @throws IOException if source or destination is invalid
      * @throws IOException if an IO error occurs during copying
      * @since 1.1
      */
     public static void copyDirectory(final File srcDir, final File destDir,
             final boolean preserveFileDate) throws IOException {
         copyDirectory(srcDir, destDir, null, preserveFileDate);
     }
 
     /**
      * Copies a filtered directory to a new location preserving the file dates.
      * <p>
      * This method copies the contents of the specified source directory
      * to within the specified destination directory.
      * <p>
      * The destination directory is created if it does not exist.
      * If the destination directory did exist, then this method merges
      * the source with the destination, with the source taking precedence.
      * <p>
      * <strong>Note:</strong> This method tries to preserve the files' last
      * modified date/times using {@link File#setLastModified(long)}, however
      * it is not guaranteed that those operations will succeed.
      * If the modification operation fails, no indication is provided.
      *
      * <h4>Example: Copy directories only</h4>
      *  <pre>
      *  // only copy the directory structure
      *  FileUtils.copyDirectory(srcDir, destDir, DirectoryFileFilter.DIRECTORY);
      *  </pre>
      *
      * <h4>Example: Copy directories and txt files</h4>
      *  <pre>
      *  // Create a filter for ".txt" files
      *  IOFileFilter txtSuffixFilter = FileFilterUtils.suffixFileFilter(".txt");
      *  IOFileFilter txtFiles = FileFilterUtils.andFileFilter(FileFileFilter.FILE, txtSuffixFilter);
      *
      *  // Create a filter for either directories or ".txt" files
      *  FileFilter filter = FileFilterUtils.orFileFilter(DirectoryFileFilter.DIRECTORY, txtFiles);
      *
      *  // Copy using the filter
      *  FileUtils.copyDirectory(srcDir, destDir, filter);
      *  </pre>
      *
      * @param srcDir  an existing directory to copy, must not be {@code null}
      * @param destDir  the new directory, must not be {@code null}
      * @param filter  the filter to apply, null means copy all directories and files
      *  should be the same as the original
      *
      * @throws NullPointerException if source or destination is {@code null}
      * @throws IOException if source or destination is invalid
      * @throws IOException if an IO error occurs during copying
      * @since 1.4
      */
     public static void copyDirectory(final File srcDir, final File destDir,
             final FileFilter filter) throws IOException {
         copyDirectory(srcDir, destDir, filter, true);
     }
 
     /**
      * Copies a filtered directory to a new location.
      * <p>
      * This method copies the contents of the specified source directory
      * to within the specified destination directory.
      * <p>
      * The destination directory is created if it does not exist.
      * If the destination directory did exist, then this method merges
      * the source with the destination, with the source taking precedence.
      * <p>
      * <strong>Note:</strong> Setting <code>preserveFileDate</code> to
      * {@code true} tries to preserve the files' last modified
      * date/times using {@link File#setLastModified(long)}, however it is
      * not guaranteed that those operations will succeed.
      * If the modification operation fails, no indication is provided.
      *
      * <h4>Example: Copy directories only</h4>
      *  <pre>
      *  // only copy the directory structure
      *  FileUtils.copyDirectory(srcDir, destDir, DirectoryFileFilter.DIRECTORY, false);
      *  </pre>
      *
      * <h4>Example: Copy directories and txt files</h4>
      *  <pre>
      *  // Create a filter for ".txt" files
      *  IOFileFilter txtSuffixFilter = FileFilterUtils.suffixFileFilter(".txt");
      *  IOFileFilter txtFiles = FileFilterUtils.andFileFilter(FileFileFilter.FILE, txtSuffixFilter);
      *
      *  // Create a filter for either directories or ".txt" files
      *  FileFilter filter = FileFilterUtils.orFileFilter(DirectoryFileFilter.DIRECTORY, txtFiles);
      *
      *  // Copy using the filter
      *  FileUtils.copyDirectory(srcDir, destDir, filter, false);
      *  </pre>
      *
      * @param srcDir  an existing directory to copy, must not be {@code null}
      * @param destDir  the new directory, must not be {@code null}
      * @param filter  the filter to apply, null means copy all directories and files
      * @param preserveFileDate  true if the file date of the copy
      *  should be the same as the original
      *
      * @throws NullPointerException if source or destination is {@code null}
      * @throws IOException if source or destination is invalid
      * @throws IOException if an IO error occurs during copying
      * @since 1.4
      */
     public static void copyDirectory(final File srcDir, final File destDir,
             final FileFilter filter, final boolean preserveFileDate) throws IOException {
         if (srcDir == null) {
             throw new NullPointerException("Source must not be null");
         }
         if (destDir == null) {
             throw new NullPointerException("Destination must not be null");
         }
         if (srcDir.exists() == false) {
             throw new FileNotFoundException("Source '" + srcDir + "' does not exist");
         }
         if (srcDir.isDirectory() == false) {
             throw new IOException("Source '" + srcDir + "' exists but is not a directory");
         }
         if (srcDir.getCanonicalPath().equals(destDir.getCanonicalPath())) {
             throw new IOException("Source '" + srcDir + "' and destination '" + destDir + "' are the same");
         }
 
         // Cater for destination being directory within the source directory (see IO-141)
         List<String> exclusionList = null;
         if (destDir.getCanonicalPath().startsWith(srcDir.getCanonicalPath())) {
             final File[] srcFiles = filter == null ? srcDir.listFiles() : srcDir.listFiles(filter);
             if (srcFiles != null && srcFiles.length > 0) {
                 exclusionList = new ArrayList<String>(srcFiles.length);
                 for (final File srcFile : srcFiles) {
                     final File copiedFile = new File(destDir, srcFile.getName());
                     exclusionList.add(copiedFile.getCanonicalPath());
                 }
             }
         }
         doCopyDirectory(srcDir, destDir, filter, preserveFileDate, exclusionList);
     }
 
     /**
      * Internal copy directory method.
      *
      * @param srcDir  the validated source directory, must not be {@code null}
      * @param destDir  the validated destination directory, must not be {@code null}
      * @param filter  the filter to apply, null means copy all directories and files
      * @param preserveFileDate  whether to preserve the file date
      * @param exclusionList  List of files and directories to exclude from the copy, may be null
      * @throws IOException if an error occurs
      * @since 1.1
      */
     private static void doCopyDirectory(final File srcDir, final File destDir, final FileFilter filter,
             final boolean preserveFileDate, final List<String> exclusionList) throws IOException {
         // recurse
         final File[] srcFiles = filter == null ? srcDir.listFiles() : srcDir.listFiles(filter);
         if (srcFiles == null) {  // null if abstract pathname does not denote a directory, or if an I/O error occurs
             throw new IOException("Failed to list contents of " + srcDir);
         }
         if (destDir.exists()) {
             if (destDir.isDirectory() == false) {
                 throw new IOException("Destination '" + destDir + "' exists but is not a directory");
             }
         } else {
             if (!destDir.mkdirs() && !destDir.isDirectory()) {
                 throw new IOException("Destination '" + destDir + "' directory cannot be created");
             }
         }
         if (destDir.canWrite() == false) {
             throw new IOException("Destination '" + destDir + "' cannot be written to");
         }
         for (final File srcFile : srcFiles) {
             final File dstFile = new File(destDir, srcFile.getName());
             if (exclusionList == null || !exclusionList.contains(srcFile.getCanonicalPath())) {
                 if (srcFile.isDirectory()) {
                     doCopyDirectory(srcFile, dstFile, filter, preserveFileDate, exclusionList);
                 } else {
                     doCopyFile(srcFile, dstFile, preserveFileDate);
                 }
             }
         }
 
         // Do this last, as the above has probably affected directory metadata
         if (preserveFileDate) {
             destDir.setLastModified(srcDir.lastModified());
         }
     }
 
     //-----------------------------------------------------------------------
     /**
      * Copies bytes from the URL <code>source</code> to a file
      * <code>destination</code>. The directories up to <code>destination</code>
      * will be created if they don't already exist. <code>destination</code>
      * will be overwritten if it already exists.
      * <p>
      * Warning: this method does not set a connection or read timeout and thus
      * might block forever. Use {@link #copyURLToFile(URL, File, int, int)}
      * with reasonable timeouts to prevent this.
      *
      * @param source  the <code>URL</code> to copy bytes from, must not be {@code null}
      * @param destination  the non-directory <code>File</code> to write bytes to
      *  (possibly overwriting), must not be {@code null}
      * @throws IOException if <code>source</code> URL cannot be opened
      * @throws IOException if <code>destination</code> is a directory
      * @throws IOException if <code>destination</code> cannot be written
      * @throws IOException if <code>destination</code> needs creating but can't be
      * @throws IOException if an IO error occurs during copying
      */
     public static void copyURLToFile(final URL source, final File destination) throws IOException {
         copyInputStreamToFile(source.openStream(), destination);
     }
 
     /**
      * Copies bytes from the URL <code>source</code> to a file
      * <code>destination</code>. The directories up to <code>destination</code>
      * will be created if they don't already exist. <code>destination</code>
      * will be overwritten if it already exists.
      *
      * @param source  the <code>URL</code> to copy bytes from, must not be {@code null}
      * @param destination  the non-directory <code>File</code> to write bytes to
      *  (possibly overwriting), must not be {@code null}
      * @param connectionTimeout the number of milliseconds until this method
      *  will timeout if no connection could be established to the <code>source</code>
      * @param readTimeout the number of milliseconds until this method will
      *  timeout if no data could be read from the <code>source</code>
      * @throws IOException if <code>source</code> URL cannot be opened
      * @throws IOException if <code>destination</code> is a directory
      * @throws IOException if <code>destination</code> cannot be written
      * @throws IOException if <code>destination</code> needs creating but can't be
      * @throws IOException if an IO error occurs during copying
      * @since 2.0
      */
     public static void copyURLToFile(final URL source, final File destination,
             final int connectionTimeout, final int readTimeout) throws IOException {
         final URLConnection connection = source.openConnection();
         connection.setConnectTimeout(connectionTimeout);
         connection.setReadTimeout(readTimeout);
         copyInputStreamToFile(connection.getInputStream(), destination);
     }
 
     /**
      * Copies bytes from an {@link InputStream} <code>source</code> to a file
      * <code>destination</code>. The directories up to <code>destination</code>
      * will be created if they don't already exist. <code>destination</code>
      * will be overwritten if it already exists.
      * The {@code source} stream is closed.
      *
      * @param source  the <code>InputStream</code> to copy bytes from, must not be {@code null}, will be closed
      * @param destination  the non-directory <code>File</code> to write bytes to
      *  (possibly overwriting), must not be {@code null}
      * @throws IOException if <code>destination</code> is a directory
      * @throws IOException if <code>destination</code> cannot be written
      * @throws IOException if <code>destination</code> needs creating but can't be
      * @throws IOException if an IO error occurs during copying
      * @since 2.0
      */
     public static void copyInputStreamToFile(final InputStream source, final File destination) throws IOException {
         try {
             copyToFile(source, destination);
         } finally {
             IOUtils.closeQuietly(source);
         }
     }
 
     /**
      * Copies bytes from an {@link InputStream} <code>source</code> to a file
      * <code>destination</code>. The directories up to <code>destination</code>
      * will be created if they don't already exist. <code>destination</code>
      * will be overwritten if it already exists.
      * The {@code source} stream is closed.
      *
      * @param source  the <code>InputStream</code> to copy bytes from, must not be {@code null}
      * @param destination  the non-directory <code>File</code> to write bytes to
      *  (possibly overwriting), must not be {@code null}
      * @throws IOException if <code>destination</code> is a directory
      * @throws IOException if <code>destination</code> cannot be written
      * @throws IOException if <code>destination</code> needs creating but can't be
      * @throws IOException if an IO error occurs during copying
      * @since 2.5
      */
     public static void copyToFile(final InputStream source, final File destination) throws IOException {
         final FileOutputStream output = openOutputStream(destination);
         try {
             IOUtils.copy(source, output);
             output.close(); // don't swallow close Exception if copy completes normally
         } finally {
             IOUtils.closeQuietly(output);
         }
     }
 
     //-----------------------------------------------------------------------
     /**
      * Deletes a directory recursively.
      *
      * @param directory  directory to delete
      * @throws IOException in case deletion is unsuccessful
      */
     public static void deleteDirectory(final File directory) throws IOException {
         if (!directory.exists()) {
             return;
         }
 
         if (!isSymlink(directory)) {
             cleanDirectory(directory);
         }
 
         if (!directory.delete()) {
             final String message =
                 "Unable to delete directory " + directory + ".";
             throw new IOException(message);
         }
     }
 
     /**
      * Deletes a file, never throwing an exception. If file is a directory, delete it and all sub-directories.
      * <p>
      * The difference between File.delete() and this method are:
      * <ul>
      * <li>A directory to be deleted does not have to be empty.</li>
      * <li>No exceptions are thrown when a file or directory cannot be deleted.</li>
      * </ul>
      *
      * @param file  file or directory to delete, can be {@code null}
      * @return {@code true} if the file or directory was deleted, otherwise
      * {@code false}
      *
      * @since 1.4
      */
     public static boolean deleteQuietly(final File file) {
         if (file == null) {
             return false;
         }
         try {
             if (file.isDirectory()) {
                 cleanDirectory(file);
             }
         } catch (final Exception ignored) {
         }
 
         try {
             return file.delete();
         } catch (final Exception ignored) {
             return false;
         }
     }
 
     /**
      * Determines whether the {@code parent} directory contains the {@code child} element (a file or directory).
      * <p>
      * Files are normalized before comparison.
      * </p>
      *
      * Edge cases:
      * <ul>
      * <li>A {@code directory} must not be null: if null, throw IllegalArgumentException</li>
      * <li>A {@code directory} must be a directory: if not a directory, throw IllegalArgumentException</li>
      * <li>A directory does not contain itself: return false</li>
      * <li>A null child file is not contained in any parent: return false</li>
      * </ul>
      *
      * @param directory
      *            the file to consider as the parent.
      * @param child
      *            the file to consider as the child.
      * @return true is the candidate leaf is under by the specified composite. False otherwise.
      * @throws IOException
      *             if an IO error occurs while checking the files.
      * @since 2.2
      * @see FilenameUtils#directoryContains(String, String)
      */
     public static boolean directoryContains(final File directory, final File child) throws IOException {
 
         // Fail fast against NullPointerException
         if (directory == null) {
             throw new IllegalArgumentException("Directory must not be null");
         }
 
         if (!directory.isDirectory()) {
             throw new IllegalArgumentException("Not a directory: " + directory);
         }
 
         if (child == null) {
             return false;
         }
 
         if (!directory.exists() || !child.exists()) {
             return false;
         }
 
         // Canonicalize paths (normalizes relative paths)
         final String canonicalParent = directory.getCanonicalPath();
         final String canonicalChild = child.getCanonicalPath();
 
         return FilenameUtils.directoryContains(canonicalParent, canonicalChild);
     }
 
     /**
      * Cleans a directory without deleting it.
      *
      * @param directory directory to clean
      * @throws IOException in case cleaning is unsuccessful
      */
     public static void cleanDirectory(final File directory) throws IOException {
         if (!directory.exists()) {
             final String message = directory + " does not exist";
             throw new IllegalArgumentException(message);
         }
 
         if (!directory.isDirectory()) {
             final String message = directory + " is not a directory";
             throw new IllegalArgumentException(message);
         }
 
         final File[] files = directory.listFiles();
         if (files == null) {  // null if security restricted
             throw new IOException("Failed to list contents of " + directory);
         }
 
         IOException exception = null;
         for (final File file : files) {
             try {
                 forceDelete(file);
             } catch (final IOException ioe) {
                 exception = ioe;
             }
         }
 
         if (null != exception) {
             throw exception;
         }
     }
 
     //-----------------------------------------------------------------------
     /**
      * Waits for NFS to propagate a file creation, imposing a timeout.
      * <p>
      * This method repeatedly tests {@link File#exists()} until it returns
      * true up to the maximum time specified in seconds.
      *
      * @param file  the file to check, must not be {@code null}
      * @param seconds  the maximum time in seconds to wait
      * @return true if file exists
      * @throws NullPointerException if the file is {@code null}
      */
     public static boolean waitFor(final File file, final int seconds) {
         int timeout = 0;
         int tick = 0;
         while (!file.exists()) {
             if (tick++ >= 10) {
                 tick = 0;
                 if (timeout++ > seconds) {
                     return false;
                 }
             }
             try {
                 Thread.sleep(100);
             } catch (final InterruptedException ignore) {
                 // ignore exception
             } catch (final Exception ex) {
                 break;
             }
         }
         return true;
     }
 
     //-----------------------------------------------------------------------
     /**
      * Reads the contents of a file into a String.
      * The file is always closed.
      *
      * @param file  the file to read, must not be {@code null}
      * @param encoding  the encoding to use, {@code null} means platform default
      * @return the file contents, never {@code null}
      * @throws IOException in case of an I/O error
      * @since 2.3
      */
     public static String readFileToString(final File file, final Charset encoding) throws IOException {
         InputStream in = null;
         try {
             in = openInputStream(file);
             return IOUtils.toString(in, Charsets.toCharset(encoding));
         } finally {
             IOUtils.closeQuietly(in);
         }
     }
 
     /**
      * Reads the contents of a file into a String. The file is always closed.
      *
      * @param file
      *            the file to read, must not be {@code null}
      * @param encoding
      *            the encoding to use, {@code null} means platform default
      * @return the file contents, never {@code null}
      * @throws IOException
      *             in case of an I/O error
      * @throws UnsupportedCharsetException
      *             thrown instead of {@link UnsupportedEncodingException} in version 2.2 if the encoding is not
      *             supported.
      * @since 2.3
      */
     public static String readFileToString(final File file, final String encoding) throws IOException {
         return readFileToString(file, Charsets.toCharset(encoding));
     }
 
 
     /**
      * Reads the contents of a file into a String using the default encoding for the VM.
      * The file is always closed.
      *
      * @param file  the file to read, must not be {@code null}
      * @return the file contents, never {@code null}
      * @throws IOException in case of an I/O error
      * @since 1.3.1
      * @deprecated 2.5 use {@link #readFileToString(File, Charset)} instead
      */
     @Deprecated
     public static String readFileToString(final File file) throws IOException {
         return readFileToString(file, Charset.defaultCharset());
     }
 
     /**
      * Reads the contents of a file into a byte array.
      * The file is always closed.
      *
      * @param file  the file to read, must not be {@code null}
      * @return the file contents, never {@code null}
      * @throws IOException in case of an I/O error
      * @since 1.1
      */
     public static byte[] readFileToByteArray(final File file) throws IOException {
         InputStream in = null;
         try {
             in = openInputStream(file);
             return IOUtils.toByteArray(in, file.length());
         } finally {
             IOUtils.closeQuietly(in);
         }
     }
 
     /**
      * Reads the contents of a file line by line to a List of Strings.
      * The file is always closed.
      *
      * @param file  the file to read, must not be {@code null}
      * @param encoding  the encoding to use, {@code null} means platform default
      * @return the list of Strings representing each line in the file, never {@code null}
      * @throws IOException in case of an I/O error
      * @since 2.3
      */
     public static List<String> readLines(final File file, final Charset encoding) throws IOException {
         InputStream in = null;
         try {
             in = openInputStream(file);
             return IOUtils.readLines(in, Charsets.toCharset(encoding));
         } finally {
             IOUtils.closeQuietly(in);
         }
     }
 
     /**
      * Reads the contents of a file line by line to a List of Strings. The file is always closed.
      *
      * @param file
      *            the file to read, must not be {@code null}
      * @param encoding
      *            the encoding to use, {@code null} means platform default
      * @return the list of Strings representing each line in the file, never {@code null}
      * @throws IOException
      *             in case of an I/O error
      * @throws UnsupportedCharsetException
      *             thrown instead of {@link UnsupportedEncodingException} in version 2.2 if the encoding is not
      *             supported.
      * @since 1.1
      */
     public static List<String> readLines(final File file, final String encoding) throws IOException {
         return readLines(file, Charsets.toCharset(encoding));
     }
 
     /**
      * Reads the contents of a file line by line to a List of Strings using the default encoding for the VM.
      * The file is always closed.
      *
      * @param file  the file to read, must not be {@code null}
      * @return the list of Strings representing each line in the file, never {@code null}
      * @throws IOException in case of an I/O error
      * @since 1.3
      * @deprecated 2.5 use {@link #readLines(File, Charset)} instead
      */
     @Deprecated
     public static List<String> readLines(final File file) throws IOException {
         return readLines(file, Charset.defaultCharset());
     }
 
     /**
      * Returns an Iterator for the lines in a <code>File</code>.
      * <p>
      * This method opens an <code>InputStream</code> for the file.
      * When you have finished with the iterator you should close the stream
      * to free internal resources. This can be done by calling the
      * {@link LineIterator#close()} or
      * {@link LineIterator#closeQuietly(LineIterator)} method.
      * <p>
      * The recommended usage pattern is:
      * <pre>
      * LineIterator it = FileUtils.lineIterator(file, "UTF-8");
      * try {
      *   while (it.hasNext()) {
      *     String line = it.nextLine();
      *     /// do something with line
      *   }
      * } finally {
      *   LineIterator.closeQuietly(iterator);
      * }
      * </pre>
      * <p>
      * If an exception occurs during the creation of the iterator, the
      * underlying stream is closed.
      *
      * @param file  the file to open for input, must not be {@code null}
      * @param encoding  the encoding to use, {@code null} means platform default
      * @return an Iterator of the lines in the file, never {@code null}
      * @throws IOException in case of an I/O error (file closed)
      * @since 1.2
      */
     public static LineIterator lineIterator(final File file, final String encoding) throws IOException {
         InputStream in = null;
         try {
             in = openInputStream(file);
             return IOUtils.lineIterator(in, encoding);
         } catch (final IOException ex) {
             IOUtils.closeQuietly(in);
             throw ex;
         } catch (final RuntimeException ex) {
             IOUtils.closeQuietly(in);
             throw ex;
         }
     }
 
     /**
      * Returns an Iterator for the lines in a <code>File</code> using the default encoding for the VM.
      *
      * @param file  the file to open for input, must not be {@code null}
      * @return an Iterator of the lines in the file, never {@code null}
      * @throws IOException in case of an I/O error (file closed)
      * @since 1.3
      * @see #lineIterator(File, String)
      */
     public static LineIterator lineIterator(final File file) throws IOException {
         return lineIterator(file, null);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Writes a String to a file creating the file if it does not exist.
      *
      * NOTE: As from v1.3, the parent directories of the file will be created
      * if they do not exist.
      *
      * @param file  the file to write
      * @param data  the content to write to the file
      * @param encoding  the encoding to use, {@code null} means platform default
      * @throws IOException in case of an I/O error
      * @throws java.io.UnsupportedEncodingException if the encoding is not supported by the VM
      * @since 2.4
      */
     public static void writeStringToFile(final File file, final String data, final Charset encoding) throws IOException {
         writeStringToFile(file, data, encoding, false);
     }
 
     /**
      * Writes a String to a file creating the file if it does not exist.
      *
      * NOTE: As from v1.3, the parent directories of the file will be created
      * if they do not exist.
      *
      * @param file  the file to write
      * @param data  the content to write to the file
      * @param encoding  the encoding to use, {@code null} means platform default
      * @throws IOException in case of an I/O error
      * @throws java.io.UnsupportedEncodingException if the encoding is not supported by the VM
      */
     public static void writeStringToFile(final File file, final String data, final String encoding) throws IOException {
         writeStringToFile(file, data, encoding, false);
     }
 
     /**
      * Writes a String to a file creating the file if it does not exist.
      *
      * @param file  the file to write
      * @param data  the content to write to the file
      * @param encoding  the encoding to use, {@code null} means platform default
      * @param append if {@code true}, then the String will be added to the
      * end of the file rather than overwriting
      * @throws IOException in case of an I/O error
      * @since 2.3
      */
     public static void writeStringToFile(final File file, final String data, final Charset encoding, final boolean append) throws IOException {
         OutputStream out = null;
         try {
             out = openOutputStream(file, append);
             IOUtils.write(data, out, encoding);
             out.close(); // don't swallow close Exception if copy completes normally
         } finally {
             IOUtils.closeQuietly(out);
         }
     }
 
     /**
      * Writes a String to a file creating the file if it does not exist.
      *
      * @param file  the file to write
      * @param data  the content to write to the file
      * @param encoding  the encoding to use, {@code null} means platform default
      * @param append if {@code true}, then the String will be added to the
      * end of the file rather than overwriting
      * @throws IOException in case of an I/O error
      * @throws UnsupportedCharsetException
      *             thrown instead of {@link UnsupportedEncodingException} in version 2.2 if the encoding is not
      *             supported by the VM
      * @since 2.1
      */
     public static void writeStringToFile(final File file, final String data, final String encoding, final boolean append) throws IOException {
         writeStringToFile(file, data, Charsets.toCharset(encoding), append);
     }
 
     /**
      * Writes a String to a file creating the file if it does not exist using the default encoding for the VM.
      *
      * @param file  the file to write
      * @param data  the content to write to the file
      * @throws IOException in case of an I/O error
      * @deprecated 2.5 use {@link #writeStringToFile(File, String, Charset)} instead
      */
     @Deprecated
     public static void writeStringToFile(final File file, final String data) throws IOException {
         writeStringToFile(file, data, Charset.defaultCharset(), false);
     }
 
     /**
      * Writes a String to a file creating the file if it does not exist using the default encoding for the VM.
      *
      * @param file  the file to write
      * @param data  the content to write to the file
      * @param append if {@code true}, then the String will be added to the
      * end of the file rather than overwriting
      * @throws IOException in case of an I/O error
      * @since 2.1
      * @deprecated 2.5 use {@link #writeStringToFile(File, String, Charset, boolean)} instead
      */
     @Deprecated
     public static void writeStringToFile(final File file, final String data, final boolean append) throws IOException {
         writeStringToFile(file, data, Charset.defaultCharset(), append);
     }
 
     /**
      * Writes a CharSequence to a file creating the file if it does not exist using the default encoding for the VM.
      *
      * @param file  the file to write
      * @param data  the content to write to the file
      * @throws IOException in case of an I/O error
      * @since 2.0
      * @deprecated 2.5 use {@link #write(File, CharSequence, Charset)} instead
      */
     @Deprecated
     public static void write(final File file, final CharSequence data) throws IOException {
         write(file, data, Charset.defaultCharset(), false);
     }
 
     /**
      * Writes a CharSequence to a file creating the file if it does not exist using the default encoding for the VM.
      *
      * @param file  the file to write
      * @param data  the content to write to the file
      * @param append if {@code true}, then the data will be added to the
      * end of the file rather than overwriting
      * @throws IOException in case of an I/O error
      * @since 2.1
      * @deprecated 2.5 use {@link #write(File, CharSequence, Charset, boolean)} instead
      */
     @Deprecated
     public static void write(final File file, final CharSequence data, final boolean append) throws IOException {
         write(file, data, Charset.defaultCharset(), append);
     }
 
     /**
      * Writes a CharSequence to a file creating the file if it does not exist.
      *
      * @param file  the file to write
      * @param data  the content to write to the file
      * @param encoding  the encoding to use, {@code null} means platform default
      * @throws IOException in case of an I/O error
      * @since 2.3
      */
     public static void write(final File file, final CharSequence data, final Charset encoding) throws IOException {
         write(file, data, encoding, false);
     }
 
     /**
      * Writes a CharSequence to a file creating the file if it does not exist.
      *
      * @param file  the file to write
      * @param data  the content to write to the file
      * @param encoding  the encoding to use, {@code null} means platform default
      * @throws IOException in case of an I/O error
      * @throws java.io.UnsupportedEncodingException if the encoding is not supported by the VM
      * @since 2.0
      */
     public static void write(final File file, final CharSequence data, final String encoding) throws IOException {
         write(file, data, encoding, false);
     }
 
     /**
      * Writes a CharSequence to a file creating the file if it does not exist.
      *
      * @param file  the file to write
      * @param data  the content to write to the file
      * @param encoding  the encoding to use, {@code null} means platform default
      * @param append if {@code true}, then the data will be added to the
      * end of the file rather than overwriting
      * @throws IOException in case of an I/O error
      * @since 2.3
      */
     public static void write(final File file, final CharSequence data, final Charset encoding, final boolean append) throws IOException {
         final String str = data == null ? null : data.toString();
         writeStringToFile(file, str, encoding, append);
     }
 
     /**
      * Writes a CharSequence to a file creating the file if it does not exist.
      *
      * @param file  the file to write
      * @param data  the content to write to the file
      * @param encoding  the encoding to use, {@code null} means platform default
      * @param append if {@code true}, then the data will be added to the
      * end of the file rather than overwriting
      * @throws IOException in case of an I/O error
      * @throws UnsupportedCharsetException
      *             thrown instead of {@link UnsupportedEncodingException} in version 2.2 if the encoding is not
      *             supported by the VM
      * @since 2.1
      */
     public static void write(final File file, final CharSequence data, final String encoding, final boolean append) throws IOException {
         write(file, data, Charsets.toCharset(encoding), append);
     }
 
     /**
      * Writes a byte array to a file creating the file if it does not exist.
      * <p>
      * NOTE: As from v1.3, the parent directories of the file will be created
      * if they do not exist.
      *
      * @param file  the file to write to
      * @param data  the content to write to the file
      * @throws IOException in case of an I/O error
      * @since 1.1
      */
     public static void writeByteArrayToFile(final File file, final byte[] data) throws IOException {
         writeByteArrayToFile(file, data, false);
     }
 
     /**
      * Writes a byte array to a file creating the file if it does not exist.
      *
      * @param file  the file to write to
      * @param data  the content to write to the file
      * @param append if {@code true}, then bytes will be added to the
      * end of the file rather than overwriting
      * @throws IOException in case of an I/O error
      * @since 2.1
      */
     public static void writeByteArrayToFile(final File file, final byte[] data, final boolean append) throws IOException {
         writeByteArrayToFile(file, data, 0, data.length, append);
     }
 
     /**
      * Writes {@code len} bytes from the specified byte array starting
      * at offset {@code off} to a file, creating the file if it does
      * not exist.
      *
      * @param file  the file to write to
      * @param data  the content to write to the file
      * @param off   the start offset in the data
      * @param len   the number of bytes to write
      * @throws IOException in case of an I/O error
      * @since 2.5
      */
     public static void writeByteArrayToFile(final File file, final byte[] data, final int off, final int len) throws IOException {
         writeByteArrayToFile(file, data, off, len, false);
     }
 
     /**
      * Writes {@code len} bytes from the specified byte array starting
      * at offset {@code off} to a file, creating the file if it does
      * not exist.
      *
      * @param file  the file to write to
      * @param data  the content to write to the file
      * @param off   the start offset in the data
      * @param len   the number of bytes to write
      * @param append if {@code true}, then bytes will be added to the
      * end of the file rather than overwriting
      * @throws IOException in case of an I/O error
      * @since 2.5
      */
     public static void writeByteArrayToFile(final File file, final byte[] data, final int off, final int len, final boolean append) throws IOException {
         OutputStream out = null;
         try {
             out = openOutputStream(file, append);
             out.write(data, off, len);
             out.close(); // don't swallow close Exception if copy completes normally
         } finally {
             IOUtils.closeQuietly(out);
         }
     }
 
     /**
      * Writes the <code>toString()</code> value of each item in a collection to
      * the specified <code>File</code> line by line.
      * The specified character encoding and the default line ending will be used.
      * <p>
      * NOTE: As from v1.3, the parent directories of the file will be created
      * if they do not exist.
      *
      * @param file  the file to write to
      * @param encoding  the encoding to use, {@code null} means platform default
      * @param lines  the lines to write, {@code null} entries produce blank lines
      * @throws IOException in case of an I/O error
      * @throws java.io.UnsupportedEncodingException if the encoding is not supported by the VM
      * @since 1.1
      */
     public static void writeLines(final File file, final String encoding, final Collection<?> lines) throws IOException {
         writeLines(file, encoding, lines, null, false);
     }
 
     /**
      * Writes the <code>toString()</code> value of each item in a collection to
      * the specified <code>File</code> line by line, optionally appending.
      * The specified character encoding and the default line ending will be used.
      *
      * @param file  the file to write to
      * @param encoding  the encoding to use, {@code null} means platform default
      * @param lines  the lines to write, {@code null} entries produce blank lines
      * @param append if {@code true}, then the lines will be added to the
      * end of the file rather than overwriting
      * @throws IOException in case of an I/O error
      * @throws java.io.UnsupportedEncodingException if the encoding is not supported by the VM
      * @since 2.1
      */
     public static void writeLines(final File file, final String encoding, final Collection<?> lines, final boolean append) throws IOException {
         writeLines(file, encoding, lines, null, append);
     }
 
     /**
      * Writes the <code>toString()</code> value of each item in a collection to
      * the specified <code>File</code> line by line.
      * The default VM encoding and the default line ending will be used.
      *
      * @param file  the file to write to
      * @param lines  the lines to write, {@code null} entries produce blank lines
      * @throws IOException in case of an I/O error
      * @since 1.3
      */
     public static void writeLines(final File file, final Collection<?> lines) throws IOException {
         writeLines(file, null, lines, null, false);
     }
 
     /**
      * Writes the <code>toString()</code> value of each item in a collection to
      * the specified <code>File</code> line by line.
      * The default VM encoding and the default line ending will be used.
      *
      * @param file  the file to write to
      * @param lines  the lines to write, {@code null} entries produce blank lines
      * @param append if {@code true}, then the lines will be added to the
      * end of the file rather than overwriting
      * @throws IOException in case of an I/O error
      * @since 2.1
      */
     public static void writeLines(final File file, final Collection<?> lines, final boolean append) throws IOException {
         writeLines(file, null, lines, null, append);
     }
 
     /**
      * Writes the <code>toString()</code> value of each item in a collection to
      * the specified <code>File</code> line by line.
      * The specified character encoding and the line ending will be used.
      * <p>
      * NOTE: As from v1.3, the parent directories of the file will be created
      * if they do not exist.
      *
      * @param file  the file to write to
      * @param encoding  the encoding to use, {@code null} means platform default
      * @param lines  the lines to write, {@code null} entries produce blank lines
      * @param lineEnding  the line separator to use, {@code null} is system default
      * @throws IOException in case of an I/O error
      * @throws java.io.UnsupportedEncodingException if the encoding is not supported by the VM
      * @since 1.1
      */
     public static void writeLines(final File file, final String encoding, final Collection<?> lines, final String lineEnding)
         throws IOException {
         writeLines(file, encoding, lines, lineEnding, false);
     }
 
     /**
      * Writes the <code>toString()</code> value of each item in a collection to
      * the specified <code>File</code> line by line.
      * The specified character encoding and the line ending will be used.
      *
      * @param file  the file to write to
      * @param encoding  the encoding to use, {@code null} means platform default
      * @param lines  the lines to write, {@code null} entries produce blank lines
      * @param lineEnding  the line separator to use, {@code null} is system default
      * @param append if {@code true}, then the lines will be added to the
      * end of the file rather than overwriting
      * @throws IOException in case of an I/O error
      * @throws java.io.UnsupportedEncodingException if the encoding is not supported by the VM
      * @since 2.1
      */
     public static void writeLines(final File file, final String encoding, final Collection<?> lines, final String lineEnding, final boolean append)
             throws IOException {
         FileOutputStream out = null;
         try {
             out = openOutputStream(file, append);
             final BufferedOutputStream buffer = new BufferedOutputStream(out);
             IOUtils.writeLines(lines, lineEnding, buffer, encoding);
             buffer.flush();
             out.close(); // don't swallow close Exception if copy completes normally
         } finally {
             IOUtils.closeQuietly(out);
         }
     }
 
     /**
      * Writes the <code>toString()</code> value of each item in a collection to
      * the specified <code>File</code> line by line.
      * The default VM encoding and the specified line ending will be used.
      *
      * @param file  the file to write to
      * @param lines  the lines to write, {@code null} entries produce blank lines
      * @param lineEnding  the line separator to use, {@code null} is system default
      * @throws IOException in case of an I/O error
      * @since 1.3
      */
     public static void writeLines(final File file, final Collection<?> lines, final String lineEnding) throws IOException {
         writeLines(file, null, lines, lineEnding, false);
     }
 
     /**
      * Writes the <code>toString()</code> value of each item in a collection to
      * the specified <code>File</code> line by line.
      * The default VM encoding and the specified line ending will be used.
      *
      * @param file  the file to write to
      * @param lines  the lines to write, {@code null} entries produce blank lines
      * @param lineEnding  the line separator to use, {@code null} is system default
      * @param append if {@code true}, then the lines will be added to the
      * end of the file rather than overwriting
      * @throws IOException in case of an I/O error
      * @since 2.1
      */
     public static void writeLines(final File file, final Collection<?> lines, final String lineEnding, final boolean append)
         throws IOException {
         writeLines(file, null, lines, lineEnding, append);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Deletes a file. If file is a directory, delete it and all sub-directories.
      * <p>
      * The difference between File.delete() and this method are:
      * <ul>
      * <li>A directory to be deleted does not have to be empty.</li>
      * <li>You get exceptions when a file or directory cannot be deleted.
      *      (java.io.File methods returns a boolean)</li>
      * </ul>
      *
      * @param file  file or directory to delete, must not be {@code null}
      * @throws NullPointerException if the directory is {@code null}
      * @throws FileNotFoundException if the file was not found
      * @throws IOException in case deletion is unsuccessful
      */
     public static void forceDelete(final File file) throws IOException {
         if (file.isDirectory()) {
             deleteDirectory(file);
         } else {
             final boolean filePresent = file.exists();
             if (!file.delete()) {
                 if (!filePresent){
                     throw new FileNotFoundException("File does not exist: " + file);
                 }
                 final String message =
                     "Unable to delete file: " + file;
                 throw new IOException(message);
             }
         }
     }
 
     /**
      * Schedules a file to be deleted when JVM exits.
      * If file is directory delete it and all sub-directories.
      *
      * @param file  file or directory to delete, must not be {@code null}
      * @throws NullPointerException if the file is {@code null}
      * @throws IOException in case deletion is unsuccessful
      */
     public static void forceDeleteOnExit(final File file) throws IOException {
         if (file.isDirectory()) {
             deleteDirectoryOnExit(file);
         } else {
             file.deleteOnExit();
         }
     }
 
     /**
      * Schedules a directory recursively for deletion on JVM exit.
      *
      * @param directory  directory to delete, must not be {@code null}
      * @throws NullPointerException if the directory is {@code null}
      * @throws IOException in case deletion is unsuccessful
      */
     private static void deleteDirectoryOnExit(final File directory) throws IOException {
         if (!directory.exists()) {
             return;
         }
 
         directory.deleteOnExit();
         if (!isSymlink(directory)) {
             cleanDirectoryOnExit(directory);
         }
     }
 
     /**
      * Cleans a directory without deleting it.
      *
      * @param directory  directory to clean, must not be {@code null}
      * @throws NullPointerException if the directory is {@code null}
      * @throws IOException in case cleaning is unsuccessful
      */
     private static void cleanDirectoryOnExit(final File directory) throws IOException {
         if (!directory.exists()) {
             final String message = directory + " does not exist";
             throw new IllegalArgumentException(message);
         }
 
         if (!directory.isDirectory()) {
             final String message = directory + " is not a directory";
             throw new IllegalArgumentException(message);
         }
 
         final File[] files = directory.listFiles();
         if (files == null) {  // null if security restricted
             throw new IOException("Failed to list contents of " + directory);
         }
 
         IOException exception = null;
         for (final File file : files) {
             try {
                 forceDeleteOnExit(file);
             } catch (final IOException ioe) {
                 exception = ioe;
             }
         }
 
         if (null != exception) {
             throw exception;
         }
     }
 
     /**
      * Makes a directory, including any necessary but nonexistent parent
      * directories. If a file already exists with specified name but it is
      * not a directory then an IOException is thrown.
      * If the directory cannot be created (or does not already exist)
      * then an IOException is thrown.
      *
      * @param directory  directory to create, must not be {@code null}
      * @throws NullPointerException if the directory is {@code null}
      * @throws IOException if the directory cannot be created or the file already exists but is not a directory
      */
     public static void forceMkdir(final File directory) throws IOException {
         if (directory.exists()) {
             if (!directory.isDirectory()) {
                 final String message =
                     "File "
                         + directory
                         + " exists and is "
                         + "not a directory. Unable to create directory.";
                 throw new IOException(message);
             }
         } else {
             if (!directory.mkdirs()) {
                 // Double-check that some other thread or process hasn't made
                 // the directory in the background
                 if (!directory.isDirectory())
                 {
                     final String message =
                         "Unable to create directory " + directory;
                     throw new IOException(message);
                 }
             }
         }
     }
 
     /**
      * Makes any necessary but nonexistent parent directories for a given File. If the parent directory cannot be
      * created then an IOException is thrown.
      *
      * @param file
      *            file with parent to create, must not be {@code null}
      * @throws NullPointerException
      *             if the file is {@code null}
      * @throws IOException
      *             if the parent directory cannot be created
      * @since 2.5
      */
     public static void forceMkdirParent(final File file) throws IOException {
         final File parent = file.getParentFile();
         if (parent == null) {
             return;
         }
         forceMkdir(parent);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Returns the size of the specified file or directory. If the provided
      * {@link File} is a regular file, then the file's length is returned.
      * If the argument is a directory, then the size of the directory is
      * calculated recursively. If a directory or subdirectory is security
      * restricted, its size will not be included.
      * <p>
      * Note that overflow is not detected, and the return value may be negative if
      * overflow occurs. See {@link #sizeOfAsBigInteger(File)} for an alternative
      * method that does not overflow.
      *
      * @param file the regular file or directory to return the size
      *        of (must not be {@code null}).
      *
      * @return the length of the file, or recursive size of the directory,
      *         provided (in bytes).
      *
      * @throws NullPointerException if the file is {@code null}
      * @throws IllegalArgumentException if the file does not exist.
      *
      * @since 2.0
      */
     public static long sizeOf(final File file) {
 
         if (!file.exists()) {
             final String message = file + " does not exist";
             throw new IllegalArgumentException(message);
         }
 
         if (file.isDirectory()) {
             return sizeOfDirectory(file);
         } else {
             return file.length();
         }
 
     }
 
     /**
      * Returns the size of the specified file or directory. If the provided
      * {@link File} is a regular file, then the file's length is returned.
      * If the argument is a directory, then the size of the directory is
      * calculated recursively. If a directory or subdirectory is security
      * restricted, its size will not be included.
      *
      * @param file the regular file or directory to return the size
      *        of (must not be {@code null}).
      *
      * @return the length of the file, or recursive size of the directory,
      *         provided (in bytes).
      *
      * @throws NullPointerException if the file is {@code null}
      * @throws IllegalArgumentException if the file does not exist.
      *
      * @since 2.4
      */
     public static BigInteger sizeOfAsBigInteger(final File file) {
 
         if (!file.exists()) {
             final String message = file + " does not exist";
             throw new IllegalArgumentException(message);
         }
 
         if (file.isDirectory()) {
             return sizeOfDirectoryAsBigInteger(file);
         } else {
             return BigInteger.valueOf(file.length());
         }
 
     }
 
     /**
      * Counts the size of a directory recursively (sum of the length of all files).
      * <p>
      * Note that overflow is not detected, and the return value may be negative if
      * overflow occurs. See {@link #sizeOfDirectoryAsBigInteger(File)} for an alternative
      * method that does not overflow.
      *
      *
      * @param directory
      *            directory to inspect, must not be {@code null}
      * @return size of directory in bytes, 0 if directory is security restricted, a negative number when the real total
      *         is greater than {@link Long#MAX_VALUE}.
      * @throws NullPointerException
      *             if the directory is {@code null}
      */
     public static long sizeOfDirectory(final File directory) {
         checkDirectory(directory);
 
         final File[] files = directory.listFiles();
         if (files == null) {  // null if security restricted
             return 0L;
         }
         long size = 0;
 
         for (final File file : files) {
             try {
                 if (!isSymlink(file)) {
                     size += sizeOf(file);
                     if (size < 0) {
                         break;
                     }
                 }
             } catch (final IOException ioe) {
                 // Ignore exceptions caught when asking if a File is a symlink.
             }
         }
 
         return size;
     }
 
     /**
      * Counts the size of a directory recursively (sum of the length of all files).
      *
      * @param directory
      *            directory to inspect, must not be {@code null}
      * @return size of directory in bytes, 0 if directory is security restricted.
      * @throws NullPointerException
      *             if the directory is {@code null}
      *  @since 2.4
      */
     public static BigInteger sizeOfDirectoryAsBigInteger(final File directory) {
         checkDirectory(directory);
 
         final File[] files = directory.listFiles();
         if (files == null) {  // null if security restricted
             return BigInteger.ZERO;
         }
         BigInteger size = BigInteger.ZERO;
 
         for (final File file : files) {
             try {
                 if (!isSymlink(file)) {
                     size = size.add(BigInteger.valueOf(sizeOf(file)));
                 }
             } catch (final IOException ioe) {
                 // Ignore exceptions caught when asking if a File is a symlink.
             }
         }
 
         return size;
     }
 
     /**
      * Checks that the given {@code File} exists and is a directory.
      *
      * @param directory The {@code File} to check.
      * @throws IllegalArgumentException if the given {@code File} does not exist or is not a directory.
      */
     private static void checkDirectory(final File directory) {
         if (!directory.exists()) {
             throw new IllegalArgumentException(directory + " does not exist");
         }
         if (!directory.isDirectory()) {
             throw new IllegalArgumentException(directory + " is not a directory");
         }
     }
 
     //-----------------------------------------------------------------------
     /**
      * Tests if the specified <code>File</code> is newer than the reference
      * <code>File</code>.
      *
      * @param file  the <code>File</code> of which the modification date must
      * be compared, must not be {@code null}
      * @param reference  the <code>File</code> of which the modification date
      * is used, must not be {@code null}
      * @return true if the <code>File</code> exists and has been modified more
      * recently than the reference <code>File</code>
      * @throws IllegalArgumentException if the file is {@code null}
      * @throws IllegalArgumentException if the reference file is {@code null} or doesn't exist
      */
      public static boolean isFileNewer(final File file, final File reference) {
         if (reference == null) {
             throw new IllegalArgumentException("No specified reference file");
         }
         if (!reference.exists()) {
             throw new IllegalArgumentException("The reference file '"
                     + reference + "' doesn't exist");
         }
         return isFileNewer(file, reference.lastModified());
     }
 
     /**
      * Tests if the specified <code>File</code> is newer than the specified
      * <code>Date</code>.
      *
      * @param file  the <code>File</code> of which the modification date
      * must be compared, must not be {@code null}
      * @param date  the date reference, must not be {@code null}
      * @return true if the <code>File</code> exists and has been modified
      * after the given <code>Date</code>.
      * @throws IllegalArgumentException if the file is {@code null}
      * @throws IllegalArgumentException if the date is {@code null}
      */
     public static boolean isFileNewer(final File file, final Date date) {
         if (date == null) {
             throw new IllegalArgumentException("No specified date");
         }
         return isFileNewer(file, date.getTime());
     }
 
     /**
      * Tests if the specified <code>File</code> is newer than the specified
      * time reference.
      *
      * @param file  the <code>File</code> of which the modification date must
      * be compared, must not be {@code null}
      * @param timeMillis  the time reference measured in milliseconds since the
      * epoch (00:00:00 GMT, January 1, 1970)
      * @return true if the <code>File</code> exists and has been modified after
      * the given time reference.
      * @throws IllegalArgumentException if the file is {@code null}
      */
      public static boolean isFileNewer(final File file, final long timeMillis) {
         if (file == null) {
             throw new IllegalArgumentException("No specified file");
         }
         if (!file.exists()) {
             return false;
         }
         return file.lastModified() > timeMillis;
     }
 
 
     //-----------------------------------------------------------------------
     /**
      * Tests if the specified <code>File</code> is older than the reference
      * <code>File</code>.
      *
      * @param file  the <code>File</code> of which the modification date must
      * be compared, must not be {@code null}
      * @param reference  the <code>File</code> of which the modification date
      * is used, must not be {@code null}
      * @return true if the <code>File</code> exists and has been modified before
      * the reference <code>File</code>
      * @throws IllegalArgumentException if the file is {@code null}
      * @throws IllegalArgumentException if the reference file is {@code null} or doesn't exist
      */
      public static boolean isFileOlder(final File file, final File reference) {
         if (reference == null) {
             throw new IllegalArgumentException("No specified reference file");
         }
         if (!reference.exists()) {
             throw new IllegalArgumentException("The reference file '"
                     + reference + "' doesn't exist");
         }
         return isFileOlder(file, reference.lastModified());
     }
 
     /**
      * Tests if the specified <code>File</code> is older than the specified
      * <code>Date</code>.
      *
      * @param file  the <code>File</code> of which the modification date
      * must be compared, must not be {@code null}
      * @param date  the date reference, must not be {@code null}
      * @return true if the <code>File</code> exists and has been modified
      * before the given <code>Date</code>.
      * @throws IllegalArgumentException if the file is {@code null}
      * @throws IllegalArgumentException if the date is {@code null}
      */
     public static boolean isFileOlder(final File file, final Date date) {
         if (date == null) {
             throw new IllegalArgumentException("No specified date");
         }
         return isFileOlder(file, date.getTime());
     }
 
     /**
      * Tests if the specified <code>File</code> is older than the specified
      * time reference.
      *
      * @param file  the <code>File</code> of which the modification date must
      * be compared, must not be {@code null}
      * @param timeMillis  the time reference measured in milliseconds since the
      * epoch (00:00:00 GMT, January 1, 1970)
      * @return true if the <code>File</code> exists and has been modified before
      * the given time reference.
      * @throws IllegalArgumentException if the file is {@code null}
      */
      public static boolean isFileOlder(final File file, final long timeMillis) {
         if (file == null) {
             throw new IllegalArgumentException("No specified file");
         }
         if (!file.exists()) {
             return false;
         }
         return file.lastModified() < timeMillis;
     }
 
     //-----------------------------------------------------------------------
     /**
      * Computes the checksum of a file using the CRC32 checksum routine.
      * The value of the checksum is returned.
      *
      * @param file  the file to checksum, must not be {@code null}
      * @return the checksum value
      * @throws NullPointerException if the file or checksum is {@code null}
      * @throws IllegalArgumentException if the file is a directory
      * @throws IOException if an IO error occurs reading the file
      * @since 1.3
      */
     public static long checksumCRC32(final File file) throws IOException {
         final CRC32 crc = new CRC32();
         checksum(file, crc);
         return crc.getValue();
     }
 
     /**
      * Computes the checksum of a file using the specified checksum object.
      * Multiple files may be checked using one <code>Checksum</code> instance
      * if desired simply by reusing the same checksum object.
      * For example:
      * <pre>
      *   long csum = FileUtils.checksum(file, new CRC32()).getValue();
      * </pre>
      *
      * @param file  the file to checksum, must not be {@code null}
      * @param checksum  the checksum object to be used, must not be {@code null}
      * @return the checksum specified, updated with the content of the file
      * @throws NullPointerException if the file or checksum is {@code null}
      * @throws IllegalArgumentException if the file is a directory
      * @throws IOException if an IO error occurs reading the file
      * @since 1.3
      */
     public static Checksum checksum(final File file, final Checksum checksum) throws IOException {
         if (file.isDirectory()) {
             throw new IllegalArgumentException("Checksums can't be computed on directories");
         }
         InputStream in = null;
         try {
             in = new CheckedInputStream(new FileInputStream(file), checksum);
             IOUtils.copy(in, new NullOutputStream());
         } finally {
             IOUtils.closeQuietly(in);
         }
         return checksum;
     }
 
     /**
      * Moves a directory.
      * <p>
      * When the destination directory is on another file system, do a "copy and delete".
      *
      * @param srcDir the directory to be moved
      * @param destDir the destination directory
      * @throws NullPointerException if source or destination is {@code null}
      * @throws FileExistsException if the destination directory exists
      * @throws IOException if source or destination is invalid
      * @throws IOException if an IO error occurs moving the file
      * @since 1.4
      */
     public static void moveDirectory(final File srcDir, final File destDir) throws IOException {
         if (srcDir == null) {
             throw new NullPointerException("Source must not be null");
         }
         if (destDir == null) {
             throw new NullPointerException("Destination must not be null");
         }
         if (!srcDir.exists()) {
             throw new FileNotFoundException("Source '" + srcDir + "' does not exist");
         }
         if (!srcDir.isDirectory()) {
             throw new IOException("Source '" + srcDir + "' is not a directory");
         }
         if (destDir.exists()) {
             throw new FileExistsException("Destination '" + destDir + "' already exists");
         }
         final boolean rename = srcDir.renameTo(destDir);
         if (!rename) {
             if (destDir.getCanonicalPath().startsWith(srcDir.getCanonicalPath() + File.separator)) {
                 throw new IOException("Cannot move directory: "+srcDir+" to a subdirectory of itself: "+destDir);
             }
             copyDirectory( srcDir, destDir );
             deleteDirectory( srcDir );
             if (srcDir.exists()) {
                 throw new IOException("Failed to delete original directory '" + srcDir +
                         "' after copy to '" + destDir + "'");
             }
         }
     }
 
     /**
      * Moves a directory to another directory.
      *
      * @param src the file to be moved
      * @param destDir the destination file
      * @param createDestDir If {@code true} create the destination directory,
      * otherwise if {@code false} throw an IOException
      * @throws NullPointerException if source or destination is {@code null}
      * @throws FileExistsException if the directory exists in the destination directory
      * @throws IOException if source or destination is invalid
      * @throws IOException if an IO error occurs moving the file
      * @since 1.4
      */
     public static void moveDirectoryToDirectory(final File src, final File destDir, final boolean createDestDir) throws IOException {
         if (src == null) {
             throw new NullPointerException("Source must not be null");
         }
         if (destDir == null) {
             throw new NullPointerException("Destination directory must not be null");
         }
         if (!destDir.exists() && createDestDir) {
             destDir.mkdirs();
         }
         if (!destDir.exists()) {
             throw new FileNotFoundException("Destination directory '" + destDir +
                     "' does not exist [createDestDir=" + createDestDir +"]");
         }
         if (!destDir.isDirectory()) {
             throw new IOException("Destination '" + destDir + "' is not a directory");
         }
         moveDirectory(src, new File(destDir, src.getName()));
 
     }
 
     /**
      * Moves a file.
      * <p>
      * When the destination file is on another file system, do a "copy and delete".
      *
      * @param srcFile the file to be moved
      * @param destFile the destination file
      * @throws NullPointerException if source or destination is {@code null}
      * @throws FileExistsException if the destination file exists
      * @throws IOException if source or destination is invalid
      * @throws IOException if an IO error occurs moving the file
      * @since 1.4
      */
     public static void moveFile(final File srcFile, final File destFile) throws IOException {
         if (srcFile == null) {
             throw new NullPointerException("Source must not be null");
         }
         if (destFile == null) {
             throw new NullPointerException("Destination must not be null");
         }
         if (!srcFile.exists()) {
             throw new FileNotFoundException("Source '" + srcFile + "' does not exist");
         }
         if (srcFile.isDirectory()) {
             throw new IOException("Source '" + srcFile + "' is a directory");
         }
         if (destFile.exists()) {
             throw new FileExistsException("Destination '" + destFile + "' already exists");
         }
         if (destFile.isDirectory()) {
             throw new IOException("Destination '" + destFile + "' is a directory");
         }
         final boolean rename = srcFile.renameTo(destFile);
         if (!rename) {
             copyFile( srcFile, destFile );
             if (!srcFile.delete()) {
                 FileUtils.deleteQuietly(destFile);
                 throw new IOException("Failed to delete original file '" + srcFile +
                         "' after copy to '" + destFile + "'");
             }
         }
     }
 
     /**
      * Moves a file to a directory.
      *
      * @param srcFile the file to be moved
      * @param destDir the destination file
      * @param createDestDir If {@code true} create the destination directory,
      * otherwise if {@code false} throw an IOException
      * @throws NullPointerException if source or destination is {@code null}
      * @throws FileExistsException if the destination file exists
      * @throws IOException if source or destination is invalid
      * @throws IOException if an IO error occurs moving the file
      * @since 1.4
      */
     public static void moveFileToDirectory(final File srcFile, final File destDir, final boolean createDestDir) throws IOException {
         if (srcFile == null) {
             throw new NullPointerException("Source must not be null");
         }
         if (destDir == null) {
             throw new NullPointerException("Destination directory must not be null");
         }
         if (!destDir.exists() && createDestDir) {
             destDir.mkdirs();
         }
         if (!destDir.exists()) {
             throw new FileNotFoundException("Destination directory '" + destDir +
                     "' does not exist [createDestDir=" + createDestDir +"]");
         }
         if (!destDir.isDirectory()) {
             throw new IOException("Destination '" + destDir + "' is not a directory");
         }
         moveFile(srcFile, new File(destDir, srcFile.getName()));
     }
 
     /**
      * Moves a file or directory to the destination directory.
      * <p>
      * When the destination is on another file system, do a "copy and delete".
      *
      * @param src the file or directory to be moved
      * @param destDir the destination directory
      * @param createDestDir If {@code true} create the destination directory,
      * otherwise if {@code false} throw an IOException
      * @throws NullPointerException if source or destination is {@code null}
      * @throws FileExistsException if the directory or file exists in the destination directory
      * @throws IOException if source or destination is invalid
      * @throws IOException if an IO error occurs moving the file
      * @since 1.4
      */
     public static void moveToDirectory(final File src, final File destDir, final boolean createDestDir) throws IOException {
         if (src == null) {
             throw new NullPointerException("Source must not be null");
         }
         if (destDir == null) {
             throw new NullPointerException("Destination must not be null");
         }
         if (!src.exists()) {
             throw new FileNotFoundException("Source '" + src + "' does not exist");
         }
         if (src.isDirectory()) {
             moveDirectoryToDirectory(src, destDir, createDestDir);
         } else {
             moveFileToDirectory(src, destDir, createDestDir);
         }
     }
 
     /**
      * Determines whether the specified file is a Symbolic Link rather than an actual file.
      * <p>
      * Will not return true if there is a Symbolic Link anywhere in the path,
      * only if the specific file is.
      * <p>
      * <b>Note:</b> the current implementation always returns {@code false} if the system
      * is detected as Windows using {@link FilenameUtils#isSystemWindows()}
      * <p>
      * For code that runs on Java 1.7 or later, use the following method instead:
      * <br>
      * {@code boolean java.nio.file.Files.isSymbolicLink(Path path)}
      * @param file the file to check
      * @return true if the file is a Symbolic Link
      * @throws IOException if an IO error occurs while checking the file
      * @since 2.0
      */
     public static boolean isSymlink(final File file) throws IOException {
         if (file == null) {
             throw new NullPointerException("File must not be null");
         }
         if (FilenameUtils.isSystemWindows()) {
             return false;
         }
         File fileInCanonicalDir = null;
         if (file.getParent() == null) {
             fileInCanonicalDir = file;
         } else {
             final File canonicalDir = file.getParentFile().getCanonicalFile();
             fileInCanonicalDir = new File(canonicalDir, file.getName());
         }
 
         if (fileInCanonicalDir.getCanonicalFile().equals(fileInCanonicalDir.getAbsoluteFile())) {
             return false;
         } else {
             return true;
         }
     }
 
 }