/* * Copyright (c) 2006, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation.  Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code 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 * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */package sun.swing; import java.awt.GraphicsConfiguration;import java.awt.Image;import java.lang.ref.SoftReference;import java.util.Iterator;import java.util.LinkedList; /** * Cache is used to cache an image based on a set of arguments. */public class ImageCache {    // Maximum number of entries to cache    private int maxCount;    // The entries.    final private LinkedList<SoftReference<Entry>> entries;     public ImageCache(int maxCount) {        this.maxCount = maxCount;        entries = new LinkedList<SoftReference<Entry>>();    }     void setMaxCount(int maxCount) {        this.maxCount = maxCount;    }     public void flush() {        entries.clear();    }     private Entry getEntry(Object key, GraphicsConfiguration config,                           int w, int h, Object[] args) {        Entry entry;        Iterator<SoftReference<Entry>> iter = entries.listIterator();        while (iter.hasNext()) {            SoftReference<Entry> ref = iter.next();            entry = ref.get();            if (entry == null) {                // SoftReference was invalidated, remove the entry                iter.remove();            }            else if (entry.equals(config, w, h, args)) {                // Put most recently used entries at the head                iter.remove();                entries.addFirst(ref);                return entry;            }        }        // Entry doesn't exist        entry = new Entry(config, w, h, args);        if (entries.size() >= maxCount) {            entries.removeLast();        }        entries.addFirst(new SoftReference<Entry>(entry));        return entry;    }     /**     * Returns the cached Image, or null, for the specified arguments.     */    public Image getImage(Object key, GraphicsConfiguration config,            int w, int h, Object[] args) {        Entry entry = getEntry(key, config, w, h, args);        return entry.getImage();    }     /**     * Sets the cached image for the specified constraints.     */    public void setImage(Object key, GraphicsConfiguration config,            int w, int h, Object[] args, Image image) {        Entry entry = getEntry(key, config, w, h, args);        entry.setImage(image);    }      /**     * Caches set of arguments and Image.     */    private static class Entry {        final private GraphicsConfiguration config;        final private int w;        final private int h;        final private Object[] args;        private Image image;         Entry(GraphicsConfiguration config, int w, int h, Object[] args) {            this.config = config;            this.args = args;            this.w = w;            this.h = h;        }         public void setImage(Image image) {            this.image = image;        }         public Image getImage() {            return image;        }         public String toString() {            String value = super.toString() +                    "[ graphicsConfig=" + config +                    ", image=" + image +                    ", w=" + w + ", h=" + h;            if (args != null) {                for (int counter = 0; counter < args.length; counter++) {                    value += ", " + args[counter];                }            }            value += "]";            return value;        }         public boolean equals(GraphicsConfiguration config,                 int w, int h, Object[] args) {            if (this.w == w && this.h == h &&                    ((this.config != null && this.config.equals(config)) ||                    (this.config == null && config == null))) {                if (this.args == null && args == null) {                    return true;                }                if (this.args != null && args != null &&                        this.args.length == args.length) {                    for (int counter = args.length - 1; counter >= 0;                    counter--) {                        Object a1 = this.args[counter];                        Object a2 = args[counter];                        if ((a1 == null && a2 != null) ||                                (a1 != null && !a1.equals(a2))) {                            return false;                        }                    }                    return true;                }            }            return false;        }    }}