001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.commons.io.filefilter;
018
019 import java.io.File;
020 import java.io.Serializable;
021
022 /**
023 * Filters files based on size, can filter either smaller files or
024 * files equal to or larger than a given threshold.
025 * <p>
026 * For example, to print all files and directories in the
027 * current directory whose size is greater than 1 MB:
028 *
029 * <pre>
030 * File dir = new File(".");
031 * String[] files = dir.list( new SizeFileFilter(1024 * 1024) );
032 * for ( int i = 0; i < files.length; i++ ) {
033 * System.out.println(files[i]);
034 * }
035 * </pre>
036 *
037 * @author Rahul Akolkar
038 * @version $Id: SizeFileFilter.java 1005099 2010-10-06 16:13:01Z niallp $
039 * @since Commons IO 1.2
040 * @see FileFilterUtils#sizeFileFilter(long)
041 * @see FileFilterUtils#sizeFileFilter(long, boolean)
042 * @see FileFilterUtils#sizeRangeFileFilter(long, long)
043 */
044 public class SizeFileFilter extends AbstractFileFilter implements Serializable {
045
046 /** The size threshold. */
047 private final long size;
048 /** Whether the files accepted will be larger or smaller. */
049 private final boolean acceptLarger;
050
051 /**
052 * Constructs a new size file filter for files equal to or
053 * larger than a certain size.
054 *
055 * @param size the threshold size of the files
056 * @throws IllegalArgumentException if the size is negative
057 */
058 public SizeFileFilter(long size) {
059 this(size, true);
060 }
061
062 /**
063 * Constructs a new size file filter for files based on a certain size
064 * threshold.
065 *
066 * @param size the threshold size of the files
067 * @param acceptLarger if true, files equal to or larger are accepted,
068 * otherwise smaller ones (but not equal to)
069 * @throws IllegalArgumentException if the size is negative
070 */
071 public SizeFileFilter(long size, boolean acceptLarger) {
072 if (size < 0) {
073 throw new IllegalArgumentException("The size must be non-negative");
074 }
075 this.size = size;
076 this.acceptLarger = acceptLarger;
077 }
078
079 //-----------------------------------------------------------------------
080 /**
081 * Checks to see if the size of the file is favorable.
082 * <p>
083 * If size equals threshold and smaller files are required,
084 * file <b>IS NOT</b> selected.
085 * If size equals threshold and larger files are required,
086 * file <b>IS</b> selected.
087 *
088 * @param file the File to check
089 * @return true if the filename matches
090 */
091 @Override
092 public boolean accept(File file) {
093 boolean smaller = file.length() < size;
094 return acceptLarger ? !smaller : smaller;
095 }
096
097 /**
098 * Provide a String representaion of this file filter.
099 *
100 * @return a String representaion
101 */
102 @Override
103 public String toString() {
104 String condition = acceptLarger ? ">=" : "<";
105 return super.toString() + "(" + condition + size + ")";
106 }
107
108 }