FileName.java

/* This file is part of Wattzap Community Edition.
 *
 * Wattzap Community Edtion is free software: you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as published
 * by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Wattzap Community Edition is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Wattzap.  If not, see <http://www.gnu.org/licenses/>.
*/
package com.wattzap.utils;

/**
 * 
 * @author David George
 * @date 2nd May 2014
 */
public class FileName {
	/**
	 * Remove the file extension from a filename, that may include a path.
	 * 
	 * e.g. /path/to/myfile.jpg -> /path/to/myfile 
	 */
	public static String removeExtension(String filename) {
	    if (filename == null) {
	        return null;
	    }

	    int index = indexOfExtension(filename);

	    if (index == -1) {
	        return filename;
	    } else {
	        return filename.substring(0, index);
	    }
	}

	/**
	 * Return the file extension from a filename, including the "."
	 * 
	 * e.g. /path/to/myfile.jpg -> .jpg
	 */
	public static String getExtension(String filename) {
	    if (filename == null) {
	        return null;
	    }

	    int index = indexOfExtension(filename);

	    if (index == -1) {
	        return filename;
	    } else {
	        return filename.substring(index);
	    }
	}

	private static final char EXTENSION_SEPARATOR = '.';
	private static final char DIRECTORY_SEPARATOR = '/';

	public static int indexOfExtension(String filename) {

	    if (filename == null) {
	        return -1;
	    }

	    // Check that no directory separator appears after the 
	    // EXTENSION_SEPARATOR
	    int extensionPos = filename.lastIndexOf(EXTENSION_SEPARATOR);

	    int lastDirSeparator = filename.lastIndexOf(DIRECTORY_SEPARATOR);

	    if (lastDirSeparator > extensionPos) {
	        return -1;
	    }

	    return extensionPos;
	}

}