PrefixFileFilter.java
/*
* 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.filefilter;
import java.io.File;
import java.io.Serializable;
import java.nio.file.FileVisitResult;
import java.nio.file.Path;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.List;
import java.util.Objects;
import java.util.stream.Stream;
import org.apache.commons.io.IOCase;
import org.apache.commons.io.file.PathUtils;
/**
* Filters file names for a certain prefix.
* <p>
* For example, to print all files and directories in the
* current directory whose name starts with {@code Test}:
* </p>
* <h2>Using Classic IO</h2>
* <pre>
* File dir = FileUtils.current();
* String[] files = dir.list(new PrefixFileFilter("Test"));
* for (String file : files) {
* System.out.println(file);
* }
* </pre>
*
* <h2>Using NIO</h2>
* <pre>
* final Path dir = PathUtils.current();
* final AccumulatorPathVisitor visitor = AccumulatorPathVisitor.withLongCounters(new PrefixFileFilter("Test"));
* //
* // Walk one dir
* Files.<b>walkFileTree</b>(dir, Collections.emptySet(), 1, visitor);
* System.out.println(visitor.getPathCounters());
* System.out.println(visitor.getFileList());
* //
* visitor.getPathCounters().reset();
* //
* // Walk dir tree
* Files.<b>walkFileTree</b>(dir, visitor);
* System.out.println(visitor.getPathCounters());
* System.out.println(visitor.getDirList());
* System.out.println(visitor.getFileList());
* </pre>
* <h2>Deprecating Serialization</h2>
* <p>
* <em>Serialization is deprecated and will be removed in 3.0.</em>
* </p>
*
* @since 1.0
* @see FileFilterUtils#prefixFileFilter(String)
* @see FileFilterUtils#prefixFileFilter(String, IOCase)
*/
public class PrefixFileFilter extends AbstractFileFilter implements Serializable {
private static final long serialVersionUID = 8533897440809599867L;
/** The file name prefixes to search for */
private final String[] prefixes;
/** Whether the comparison is case-sensitive. */
private final IOCase isCase;
/**
* Constructs a new Prefix file filter for a list of prefixes.
*
* @param prefixes the prefixes to allow, must not be null
* @throws NullPointerException if the prefix list is null
* @throws ClassCastException if the list does not contain Strings
*/
public PrefixFileFilter(final List<String> prefixes) {
this(prefixes, IOCase.SENSITIVE);
}
/**
* Constructs a new Prefix file filter for a list of prefixes
* specifying case-sensitivity.
*
* @param prefixes the prefixes to allow, must not be null
* @param ioCase how to handle case sensitivity, null means case-sensitive
* @throws NullPointerException if the prefix list is null
* @throws ClassCastException if the list does not contain Strings
* @since 1.4
*/
public PrefixFileFilter(final List<String> prefixes, final IOCase ioCase) {
Objects.requireNonNull(prefixes, "prefixes");
this.prefixes = prefixes.toArray(EMPTY_STRING_ARRAY);
this.isCase = IOCase.value(ioCase, IOCase.SENSITIVE);
}
/**
* Constructs a new Prefix file filter for a single prefix.
*
* @param prefix the prefix to allow, must not be null
* @throws IllegalArgumentException if the prefix is null
*/
public PrefixFileFilter(final String prefix) {
this(prefix, IOCase.SENSITIVE);
}
/**
* Constructs a new Prefix file filter for any of an array of prefixes.
* <p>
* The array is not cloned, so could be changed after constructing the
* instance. This would be inadvisable however.
*
* @param prefixes the prefixes to allow, must not be null
* @throws IllegalArgumentException if the prefix array is null
*/
public PrefixFileFilter(final String... prefixes) {
this(prefixes, IOCase.SENSITIVE);
}
/**
* Constructs a new Prefix file filter for a single prefix
* specifying case-sensitivity.
*
* @param prefix the prefix to allow, must not be null
* @param ioCase how to handle case sensitivity, null means case-sensitive
* @throws IllegalArgumentException if the prefix is null
* @since 1.4
*/
public PrefixFileFilter(final String prefix, final IOCase ioCase) {
Objects.requireNonNull(prefix, "prefix");
this.prefixes = new String[] {prefix};
this.isCase = IOCase.value(ioCase, IOCase.SENSITIVE);
}
/**
* Constructs a new Prefix file filter for any of an array of prefixes
* specifying case-sensitivity.
*
* @param prefixes the prefixes to allow, must not be null
* @param ioCase how to handle case sensitivity, null means case-sensitive
* @throws IllegalArgumentException if the prefix is null
* @since 1.4
*/
public PrefixFileFilter(final String[] prefixes, final IOCase ioCase) {
Objects.requireNonNull(prefixes, "prefixes");
this.prefixes = prefixes.clone();
this.isCase = IOCase.value(ioCase, IOCase.SENSITIVE);
}
/**
* Checks to see if the file name starts with the prefix.
*
* @param file the File to check
* @return true if the file name starts with one of our prefixes
*/
@Override
public boolean accept(final File file) {
return accept(file == null ? null : file.getName());
}
/**
* Checks to see if the file name starts with the prefix.
*
* @param file the File directory
* @param name the file name
* @return true if the file name starts with one of our prefixes
*/
@Override
public boolean accept(final File file, final String name) {
return accept(name);
}
/**
* Checks to see if the file name starts with the prefix.
* @param file the File to check
*
* @return true if the file name starts with one of our prefixes
* @since 2.9.0
*/
@Override
public FileVisitResult accept(final Path file, final BasicFileAttributes attributes) {
return toFileVisitResult(accept(PathUtils.getFileName(file, Path::toFile)));
}
private boolean accept(final String name) {
return Stream.of(prefixes).anyMatch(prefix -> isCase.checkStartsWith(name, prefix));
}
/**
* Provide a String representation of this file filter.
*
* @return a String representation
*/
@Override
public String toString() {
final StringBuilder buffer = new StringBuilder();
buffer.append(super.toString());
buffer.append("(");
append(prefixes, buffer);
buffer.append(")");
return buffer.toString();
}
}