001 /* PAVLOV -- Multiple Choice Study System
002 * Copyright (C) 2000 - 2004 T.J. Willis
003 *
004 * This program is free software; you can redistribute it and/or
005 * modify it under the terms of the GNU General Public License
006 * as published by the Free Software Foundation; either version 2
007 * of the License, or (at your option) any later version.
008 *
009 * This program is distributed in the hope that it will be useful,
010 * but WITHOUT ANY WARRANTY; without even the implied warranty of
011 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
012 * GNU General Public License for more details.
013 *
014 * You should have received a copy of the GNU General Public License
015 * along with this program; if not, write to the Free Software
016 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
017 *
018 * $Header: /cvsroot/pavlov/net/sourceforge/pavlov/randommedia/ImageCache.java,v 1.3 2004/05/10 14:58:54 tj_willis Exp $
019 */
020 package net.sourceforge.pavlov.randommedia;
021
022
023
024 import javax.swing.ImageIcon;
025 import java.net.URL;
026 import org.apache.log4j.*;
027
028 /**
029 * Loads and holds a bunch of image files whose locations are specified
030 * relative to a fixed base URL.
031 * @author <a href="mailto:tj_willis@users.sourceforge.net">T.J. Willis</a>
032 * @version 1.0
033 */
034 public class ImageCache extends MediaCache {
035 CacheObject last = null;
036
037 /**
038 * Creates a new <code>ImageCache</code> instance.
039 *
040 * @param p a <code>RandomURLProvider</code> value
041 * @param size an <code>int</code> value
042 */
043 public ImageCache(RandomURLProvider p,int size) {
044 super(p,size);
045 }
046
047 /**
048 * Describe <code>loadCacheObject</code> method here.
049 *
050 * @return a <code>CacheObject</code> value
051 */
052 public CacheObject loadCacheObject()
053 {
054 return (CacheObject)getObject(); // def'd in MediaCache
055 }
056
057 // protected void createMediaLoader(MediaCache m,URL u, int pri)
058 // {
059 // new ImageContentLoader(m,u,pri);
060 // };
061
062 /**
063 * Describe <code>getUncachedRandomImageIcon</code> method here.
064 *
065 * @param size an <code>int</code> value
066 * @return an <code>ImageIcon</code> value
067 */
068 public ImageIcon getUncachedRandomImageIcon (int size)
069 {
070 CacheObject foo = getRandomUncachedObject();
071 if(foo==null) return null;
072 return (ImageIcon)foo.object;
073 }
074
075
076 /**
077 * Describe <code>getRandomUncachedObject</code> method here.
078 *
079 * @return a <code>CacheObject</code> value
080 */
081 public CacheObject getRandomUncachedObject()
082 {
083 ImageContentLoader ld = new ImageContentLoader();
084 assert provider!=null : "Can't get a content loader";
085 URL u = provider.getRandomURL();
086 assert u!=null : "Can't get a url from the provider";
087 CacheObject foo = (CacheObject)ld.loadContent(u);
088 return foo;
089 }
090
091 /**
092 * Describe <code>getRandomCacheObject</code> method here.
093 *
094 * @return a <code>CacheObject</code> value
095 */
096 public CacheObject getRandomCacheObject()
097 {
098 return loadCacheObject();
099 }
100
101 /**
102 * Gets a random image icon of the given size from the cache.
103 * Initializes or loads cache objects as necessary.
104 * @param size an <code>int</code> value
105 * @return an <code>ImageIcon</code> value
106 */
107 public ImageIcon getRandomImageIcon( int size )
108 {
109 if(size<1) return null;
110 CacheObject ob;
111 ob = getRandomCacheObject();
112 if(ob==null){
113 ob = getRandomUncachedObject();
114 }
115 if(ob==null) return null;
116 ImageIcon foo = (ImageIcon)ob.object;
117 if(foo==null) return null;
118 last = ob;
119 ImageIcon ret = ImageIconUtilities.formatImage(foo, size);
120 return ret;
121 }
122
123 /**
124 * If there's a null in an intermediate step, let the user know.
125 * This is useful for debugging.
126 * @param msg a <code>String</code> value
127 * @return an <code>Object</code> value
128 */
129 protected static Object nullNotifier(String msg)
130 {
131 System.out.println("NULLNOTIFIER: " +msg);
132 return null;
133 }
134
135 /**
136 * Describe <code>getContentLoader</code> method here.
137 *
138 * @return a <code>ContentLoader</code> value
139 */
140 public ContentLoader getContentLoader()
141 {
142 return new ImageContentLoader();
143 }
144 }