001/* ========================================================================
002 * JCommon : a free general purpose class library for the Java(tm) platform
003 * ========================================================================
004 *
005 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
006 * 
007 * Project Info:  http://www.jfree.org/jcommon/index.html
008 *
009 * This library is free software; you can redistribute it and/or modify it 
010 * under the terms of the GNU Lesser General Public License as published by 
011 * the Free Software Foundation; either version 2.1 of the License, or 
012 * (at your option) any later version.
013 *
014 * This library is distributed in the hope that it will be useful, but 
015 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
016 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
017 * License for more details.
018 *
019 * You should have received a copy of the GNU Lesser General Public
020 * License along with this library; if not, write to the Free Software
021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
022 * USA.  
023 *
024 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
025 * in the United States and other countries.]
026 * 
027 * ------------------
028 * FileUtilities.java
029 * ------------------
030 * (C) Copyright 2000-2004, by Object Refinery Limited.
031 *
032 * Original Author:  David Gilbert (for Object Refinery Limited);
033 * Contributor(s):   -;
034 *
035 * $Id: FileUtilities.java,v 1.5 2005/10/18 13:16:02 mungady Exp $
036 *
037 * Changes (from 5-Nov-2001)
038 * -------------------------
039 * 05-Nov-2001 : Changed package to com.jrefinery.io.* (DG);
040 * 04-Mar-2002 : Renamed Files.java --> FileUtilities.java (DG);
041 * 10-Oct-2002 : Fixed errors reported by Checkstyle (DG);
042 *
043 */
044
045package org.jfree.io;
046
047import java.io.File;
048import java.util.StringTokenizer;
049
050/**
051 * A class containing useful utility methods relating to files.
052 *
053 * @author David Gilbert
054 */
055public class FileUtilities {
056
057    /**
058     * To prevent unnecessary instantiation.
059     */
060    private FileUtilities() {
061    }
062
063    /**
064     * Returns a reference to a file with the specified name that is located
065     * somewhere on the classpath.  The code for this method is an adaptation
066     * of code supplied by Dave Postill.
067     *
068     * @param name  the filename.
069     *
070     * @return a reference to a file or <code>null</code> if no file could be found.
071     */
072    public static File findFileOnClassPath(final String name) {
073
074        final String classpath = System.getProperty("java.class.path");
075        final String pathSeparator = System.getProperty("path.separator");
076
077        final StringTokenizer tokenizer = new StringTokenizer(classpath, pathSeparator);
078
079        while (tokenizer.hasMoreTokens()) {
080            final String pathElement = tokenizer.nextToken();
081
082            final File directoryOrJar = new File(pathElement);
083            final File absoluteDirectoryOrJar = directoryOrJar.getAbsoluteFile();
084
085            if (absoluteDirectoryOrJar.isFile()) {
086                final File target = new File(absoluteDirectoryOrJar.getParent(), name);
087                if (target.exists()) {
088                    return target;
089                }
090            }
091            else {
092                final File target = new File(directoryOrJar, name);
093                if (target.exists()) {
094                    return target;
095                }
096            }
097
098        }
099        return null;
100
101    }
102
103}