/* $Id: ResourceLoader.java 18319 2010-04-20 23:50:51Z euluis $

  *****************************************************************************

  * Copyright (c) 2009 Contributors - see below

  * All rights reserved. This program and the accompanying materials

  * are made available under the terms of the Eclipse Public License v1.0

  * which accompanies this distribution, and is available at

  * http://www.eclipse.org/legal/epl-v10.html

  *

  * Contributors:

  *    tfmorris

  *****************************************************************************

  *

  * Some portions of this file was previously release using the BSD License:

  */

 // Copyright (c) 1996-2006 The Regents of the University of California. All

 // Rights Reserved. Permission to use, copy, modify, and distribute this

 // software and its documentation without fee, and without a written

 // agreement is hereby granted, provided that the above copyright notice

 // and this paragraph appear in all copies.  This software program and

 // documentation are copyrighted by The Regents of the University of

 // California. The software program and documentation are supplied "AS

 // IS", without any accompanying services from The Regents. The Regents

 // does not warrant that the operation of the program will be

 // uninterrupted or error-free. The end-user understands that the program

 // was developed for research purposes and is advised not to rely

 // exclusively on the program for any reason.  IN NO EVENT SHALL THE

 // UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,

 // SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS,

 // ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF

 // THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF

 // SUCH DAMAGE. THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY

 // WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF

 // MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE

 // PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF

 // CALIFORNIA HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT,

 // UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 package org.argouml.application.helpers;

 import java.util.ArrayList;

 import java.util.HashMap;

 import java.util.Iterator;

 import java.util.List;

 import javax.swing.Icon;

 import javax.swing.ImageIcon;

 /**

  * This class manages the resource locations needed within the application.

  * Already loaded resources are cached. The resources can be searched in

  * different locations.

  * <p>

  * Derived from org.tigris.gef.util.ResourceLoader with formatting and

  * variable naming changed to conform to ArgoUML coding standard.

  * <p>

  * We use a local copy to reduce coupling to GEF and so that GEF isn't trying

  * to do uplevel accesses to the application resources (which won't work in

  * environments that enforce strict partitioning between projects eg Eclipse).

  * 

  * @author Original Author: Thorsten Sturm

  */

 // NOTE: This is package scope to force callers to use ResourceLoaderWrapper

 class ResourceLoader {

     private static HashMap<String, Icon> resourceCache = 

         new HashMap<String, Icon>();

     private static List<String> resourceLocations = new ArrayList<String>();

     private static List<String> resourceExtensions = new ArrayList<String>();

     public static ImageIcon lookupIconResource(String resource) {

         return lookupIconResource(resource, resource);

     }

     public static ImageIcon lookupIconResource(String resource, String desc) {

         return lookupIconResource(resource, desc, null);

     }

     public static ImageIcon lookupIconResource(String resource,

             ClassLoader loader) {

         return lookupIconResource(resource, resource, loader);

     }

     /**

      * This method tries to find an ImageIcon for the given name in all known

      * locations. The file extension of the used image file can be any of the

      * known extensions.

      * 

      * @param resource

      *            Name of the image to be looked after.

      * @param desc

      *            A description for the ImageIcon.

      * @param loader

      *            The class loader that should be used for loading the resource.

      * @return ImageIcon for the given name, null if no image could be found.

      */

     public static ImageIcon lookupIconResource(String resource, String desc,

             ClassLoader loader) {

         resource = toJavaIdentifier(resource);

         if (isInCache(resource)) {

             return (ImageIcon) resourceCache.get(resource);

         }

         ImageIcon res = null;

         java.net.URL imgURL = lookupIconUrl(resource, loader);

         if (imgURL != null) {

             res = new ImageIcon(imgURL, desc);

             synchronized (resourceCache) {

                 resourceCache.put(resource, res);

             }

         }

         return res;

     }

     /**

      * Search for the given resource with one of the registered extensions, in

      * one of the registered locations. The URL of the first found is returned.

      * 

      * @param resource

      *            base name of resource to search for

      * @param loader

      *            class loader to use

      * @return URL representing first location the resource was found or null if

      *         it was not found in any of the registered locations.

      */

     static java.net.URL lookupIconUrl(String resource, 

             ClassLoader loader) {

         java.net.URL imgURL = null;

         for (Iterator extensions = resourceExtensions.iterator(); 

                 extensions.hasNext();) {

             String tmpExt = (String) extensions.next();

             for (Iterator locations = resourceLocations.iterator(); 

                     locations.hasNext();) {

                 String imageName =

                         locations.next() + "/" + resource + "." + tmpExt;

 // System.out.println("[ResourceLoader] try loading " + imageName);

                 if (loader == null) {

                     imgURL = ResourceLoader.class.getResource(imageName);

                 } else {

                     imgURL = loader.getResource(imageName);

                 }

                 if (imgURL != null) {

                     break;

                 }

             }

             if (imgURL != null) {

                 break;

             }

         }

         return imgURL;

     }

     /**

      * Adds a location (path) to the list of known locations. Locations are

      * searched in the order they are added, so for best performance add the

      * most likely locations first.

      * 

      * @param location

      *            String representation of the new location.

      */

     public static void addResourceLocation(String location) {

         if (!containsLocation(location)) {

             resourceLocations.add(location);

         }

     }

     /**

      * Add an extension to the list of known extensions. Extensions are searched

      * in the order they are added, so for best performance add the most likely

      * extensions first.

      * 

      * @param extension

      *            String representation of the new extension.

      */

     public static void addResourceExtension(String extension) {

         if (!containsExtension(extension)) {

             resourceExtensions.add(extension);

         }

     }

     /**

      * This method removes a location from the list of known locations.

      * 

      * @param location

      *            String representation of the location to be removed.

      */

     public static void removeResourceLocation(String location) {

         for (Iterator iter = resourceLocations.iterator(); iter.hasNext();) {

             String loc = (String) iter.next();

             if (loc.equals(location)) {

                 resourceLocations.remove(loc);

                 break;

             }

         }

     }

     /**

      * This method removes a extension from the list of known extensions.

      *

      * @param extension String representation of the extension to be removed.

      */

     public static void removeResourceExtension(String extension) {

         for (Iterator iter = resourceExtensions.iterator(); iter.hasNext();) {

             String ext = (String) iter.next();

             if (ext.equals(extension)) {

                 resourceExtensions.remove(ext);

                 break;

             }

         }

     }

     public static boolean containsExtension(String extension) {

         return resourceExtensions.contains(extension);

     }

     public static boolean containsLocation(String location) {

         return resourceLocations.contains(location);

     }

     public static boolean isInCache(String resource) {

         return resourceCache.containsKey(resource);

     }

     /*

      * Strip all characters out of <var>s</var> that could not be part of a

      * valid Java identifier. Return either the given string (if all characters

      * were valid), or a new string with all invalid characters stripped out.

      * This allows automatic conversion of strings containing punctuation and

      * spaces to a resource name that can be looked up.

      */

     public static final String toJavaIdentifier(String s) {

         int len = s.length();

         int pos = 0;

         for (int i = 0; i < len; i++, pos++) {

             if (!Character.isJavaIdentifierPart(s.charAt(i))) break;

         }

         if (pos == len) {

             return s;

         }

         StringBuffer buf = new StringBuffer(len);

         buf.append(s.substring(0, pos));

         // skip pos, we know it's not a valid char from above

         for (int i = pos + 1; i < len; i++) {

             char c = s.charAt(i);

             if (Character.isJavaIdentifierPart(c)) {

                 buf.append(c);

             }

         }

         return buf.toString();

     }

 } /* end class ResourceLoader */