/*
 * 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
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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.
/** * 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.
/** * 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.
/** * 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.
/** * 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; } } }