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 */
017package org.apache.commons.vfs2.filter;
018
019import java.io.Serializable;
020
021import org.apache.commons.vfs2.FileContent;
022import org.apache.commons.vfs2.FileFilter;
023import org.apache.commons.vfs2.FileObject;
024import org.apache.commons.vfs2.FileSelectInfo;
025import org.apache.commons.vfs2.FileSystemException;
026
027/**
028 * Filters files based on size, can filter either smaller files or files equal
029 * to or larger than a given threshold.
030 * <p>
031 * For example, to print all files and directories in the current directory
032 * whose size is greater than 1 MB:
033 * </p>
034 *
035 * <pre>
036 * FileSystemManager fsManager = VFS.getManager();
037 * FileObject dir = fsManager.toFileObject(new File(&quot;.&quot;));
038 * SizeFileFilter filter = new SizeFileFilter(1024 * 1024);
039 * FileObject[] files = dir.findFiles(new FileFilterSelector(filter));
040 * for (int i = 0; i &lt; files.length; i++) {
041 *     System.out.println(files[i]);
042 * }
043 * </pre>
044 *
045 * @author This code was originally ported from Apache Commons IO File Filter
046 * @see "https://commons.apache.org/proper/commons-io/"
047 * @since 2.4
048 */
049public class SizeFileFilter implements FileFilter, Serializable {
050
051    private static final long serialVersionUID = 1L;
052
053    /** Whether the files accepted will be larger or smaller. */
054    private final boolean acceptLarger;
055
056    /** The size threshold. */
057    private final long size;
058
059    /**
060     * Constructs a new size file filter for files equal to or larger than a certain
061     * size.
062     *
063     * @param size the threshold size of the files - Must be non-negative.
064     */
065    public SizeFileFilter(final long size) {
066        this(size, true);
067    }
068
069    /**
070     * Constructs a new size file filter for files based on a certain size
071     * threshold.
072     *
073     * @param size         the threshold size of the files - Must be non-negative.
074     * @param acceptLarger if true, files equal to or larger are accepted, otherwise
075     *                     smaller ones (but not equal to)
076     */
077    public SizeFileFilter(final long size, final boolean acceptLarger) {
078        if (size < 0) {
079            throw new IllegalArgumentException("The size must be non-negative");
080        }
081        this.size = size;
082        this.acceptLarger = acceptLarger;
083    }
084
085    /**
086     * Checks to see if the size of the file is favorable.
087     * <p>
088     * If size equals threshold and smaller files are required, file <strong>IS NOT</strong>
089     * selected. If size equals threshold and larger files are required, file
090     * <strong>IS</strong> selected.
091     * </p>
092     * <p>
093     * Non-existing files return always false (will never be accepted).
094     * </p>
095     *
096     * @param fileSelectInfo the File to check
097     * @return true if the file name matches
098     * @throws FileSystemException Thrown for file system errors.
099     */
100    @Override
101    public boolean accept(final FileSelectInfo fileSelectInfo) throws FileSystemException {
102        try (FileObject file = fileSelectInfo.getFile()) {
103            if (!file.exists()) {
104                return false;
105            }
106            try (FileContent content = file.getContent()) {
107                final long length = content.getSize();
108                final boolean smaller = length < size;
109                return acceptLarger != smaller;
110            }
111        }
112    }
113
114    /**
115     * Provide a String representation of this file filter.
116     *
117     * @return a String representation
118     */
119    @Override
120    public String toString() {
121        final String condition = acceptLarger ? ">=" : "<";
122        return super.toString() + "(" + condition + size + ")";
123    }
124
125}