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 */
018
019package org.apache.commons.compress.utils;
020
021import java.io.File;
022import java.nio.file.Path;
023
024/**
025 * Generic file name utilities.
026 * @since 1.20
027 */
028public class FileNameUtils {
029
030    private static String fileNameToBaseName(final String name) {
031        final int extensionIndex = name.lastIndexOf('.');
032        return extensionIndex < 0 ? name : name.substring(0, extensionIndex);
033    }
034
035    private static String fileNameToExtension(final String name) {
036        final int extensionIndex = name.lastIndexOf('.');
037        return extensionIndex < 0 ? "" : name.substring(extensionIndex + 1);
038    }
039
040    /**
041     * Gets the basename (i.e. the part up to and not including the
042     * last ".") of the last path segment of a filename.
043     * <p>Will return the file name itself if it doesn't contain any
044     * dots. All leading directories of the {@code filename} parameter
045     * are skipped.</p>
046     * @return the basename of filename
047     * @param path the path of the file to obtain the basename of.
048     * @since 1.22
049     */
050    public static String getBaseName(final Path path) {
051        if (path == null) {
052            return null;
053        }
054        final Path fileName = path.getFileName();
055        return fileName != null ? fileNameToBaseName(fileName.toString()) : null;
056    }
057
058    /**
059     * Gets the basename (i.e. the part up to and not including the
060     * last ".") of the last path segment of a filename.
061     *
062     * <p>Will return the file name itself if it doesn't contain any
063     * dots. All leading directories of the {@code filename} parameter
064     * are skipped.</p>
065     *
066     * @return the basename of filename
067     * @param filename the name of the file to obtain the basename of.
068     */
069    public static String getBaseName(final String filename) {
070        if (filename == null) {
071            return null;
072        }
073        return fileNameToBaseName(new File(filename).getName());
074    }
075
076    /**
077     * Gets the extension (i.e. the part after the last ".") of a file.
078     * <p>Will return an empty string if the file name doesn't contain
079     * any dots. Only the last segment of a the file name is consulted
080     * - i.e. all leading directories of the {@code filename}
081     * parameter are skipped.</p>
082     * @return the extension of filename
083     * @param path the path of the file to obtain the extension of.
084     * @since 1.22
085     */
086    public static String getExtension(final Path path) {
087        if (path == null) {
088            return null;
089        }
090        final Path fileName = path.getFileName();
091        return fileName != null ? fileNameToExtension(fileName.toString()) : null;
092    }
093
094    /**
095     * Gets the extension (i.e. the part after the last ".") of a file.
096     *
097     * <p>Will return an empty string if the file name doesn't contain
098     * any dots. Only the last segment of a the file name is consulted
099     * - i.e. all leading directories of the {@code filename}
100     * parameter are skipped.</p>
101     *
102     * @return the extension of filename
103     * @param filename the name of the file to obtain the extension of.
104     */
105    public static String getExtension(final String filename) {
106        if (filename == null) {
107            return null;
108        }
109        return fileNameToExtension(new File(filename).getName());
110    }
111}