001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.commons.compress.compressors.bzip2;
020
021import java.util.LinkedHashMap;
022import java.util.Map;
023import org.apache.commons.compress.compressors.FileNameUtil;
024
025/**
026 * Utility code for the BZip2 compression format.
027 * @ThreadSafe
028 * @since 1.1
029 */
030public abstract class BZip2Utils {
031
032    private static final FileNameUtil fileNameUtil;
033
034    static {
035        final Map<String, String> uncompressSuffix =
036            new LinkedHashMap<>();
037        // backwards compatibilty: BZip2Utils never created the short
038        // tbz form, so .tar.bz2 has to be added explicitly
039        uncompressSuffix.put(".tar.bz2", ".tar");
040        uncompressSuffix.put(".tbz2", ".tar");
041        uncompressSuffix.put(".tbz", ".tar");
042        uncompressSuffix.put(".bz2", "");
043        uncompressSuffix.put(".bz", "");
044        fileNameUtil = new FileNameUtil(uncompressSuffix, ".bz2");
045    }
046
047    /** Private constructor to prevent instantiation of this utility class. */
048    private BZip2Utils() {
049    }
050
051    /**
052     * Detects common bzip2 suffixes in the given filename.
053     *
054     * @param filename name of a file
055     * @return {@code true} if the filename has a common bzip2 suffix,
056     *         {@code false} otherwise
057     */
058    public static boolean isCompressedFilename(final String filename) {
059        return fileNameUtil.isCompressedFilename(filename);
060    }
061
062    /**
063     * Maps the given name of a bzip2-compressed file to the name that the
064     * file should have after uncompression. Commonly used file type specific
065     * suffixes like ".tbz" or ".tbz2" are automatically detected and
066     * correctly mapped. For example the name "package.tbz2" is mapped to
067     * "package.tar". And any filenames with the generic ".bz2" suffix
068     * (or any other generic bzip2 suffix) is mapped to a name without that
069     * suffix. If no bzip2 suffix is detected, then the filename is returned
070     * unmapped.
071     *
072     * @param filename name of a file
073     * @return name of the corresponding uncompressed file
074     */
075    public static String getUncompressedFilename(final String filename) {
076        return fileNameUtil.getUncompressedFilename(filename);
077    }
078
079    /**
080     * Maps the given filename to the name that the file should have after
081     * compression with bzip2. Currently this method simply appends the suffix
082     * ".bz2" to the filename based on the standard behaviour of the "bzip2"
083     * program, but a future version may implement a more complex mapping if
084     * a new widely used naming pattern emerges.
085     *
086     * @param filename name of a file
087     * @return name of the corresponding compressed file
088     */
089    public static String getCompressedFilename(final String filename) {
090        return fileNameUtil.getCompressedFilename(filename);
091    }
092
093}