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: * WaitingImageObserver.java
029: * -------------------------
030: * (C)opyright 2000-2004, by Thomas Morgner and Contributors.
031: *
032: * Original Author: Thomas Morgner
033: * Contributor(s): Stefan Prange;
034: *
035: * $Id: WaitingImageObserver.java,v 1.6 2006/06/28 17:15:14 taqua Exp $
036: *
037: * Changes (from 8-Feb-2002)
038: * -------------------------
039: * 15-Apr-2002 : first version used by ImageElement.
040: * 16-May-2002 : Line delimiters adjusted
041: * 04-Jun-2002 : Documentation and added a NullPointerCheck for the constructor.
042: * 14-Jul-2002 : BugFixed: WaitingImageObserver dead-locked (bugfix by Stefan
043: * Prange)
044: * 18-Mar-2003 : Updated header and made minor Javadoc changes (DG);
045: * 21-Sep-2003 : Moved from JFreeReport.
046: */
047:
048: package org.jfree.util;
049:
050: import java.awt.Graphics;
051: import java.awt.Image;
052: import java.awt.image.BufferedImage;
053: import java.awt.image.ImageObserver;
054: import java.io.Serializable;
055:
056: /**
057: * This image observer blocks until the image is completely loaded. AWT
058: * defers the loading of images until they are painted on a graphic.
059: *
060: * While printing reports it is not very nice, not to know whether a image
061: * was completely loaded, so this observer forces the loading of the image
062: * until a final state (either ALLBITS, ABORT or ERROR) is reached.
063: *
064: * @author Thomas Morgner
065: */
066: public class WaitingImageObserver implements ImageObserver,
067: Serializable, Cloneable {
068: /** For serialization. */
069: static final long serialVersionUID = -807204410581383550L;
070:
071: /** The lock. */
072: private boolean lock;
073:
074: /** The image. */
075: private Image image;
076:
077: /** A flag that signals an error. */
078: private boolean error;
079:
080: /**
081: * Creates a new <code>ImageObserver<code> for the given <code>Image<code>.
082: * The observer has to be started by an external thread.
083: *
084: * @param image the image to observe (<code>null</code> not permitted).
085: */
086: public WaitingImageObserver(final Image image) {
087: if (image == null) {
088: throw new NullPointerException();
089: }
090: this .image = image;
091: this .lock = true;
092: }
093:
094: /**
095: * Callback function used by AWT to inform that more data is available. The
096: * observer waits until either all data is loaded or AWT signals that the
097: * image cannot be loaded.
098: *
099: * @param img the image being observed.
100: * @param infoflags the bitwise inclusive OR of the following
101: * flags: <code>WIDTH</code>, <code>HEIGHT</code>,
102: * <code>PROPERTIES</code>, <code>SOMEBITS</code>,
103: * <code>FRAMEBITS</code>, <code>ALLBITS</code>,
104: * <code>ERROR</code>, <code>ABORT</code>.
105: * @param x the <i>x</i> coordinate.
106: * @param y the <i>y</i> coordinate.
107: * @param width the width.
108: * @param height the height.
109: *
110: * @return <code>false</code> if the infoflags indicate that the
111: * image is completely loaded; <code>true</code> otherwise.
112: */
113: public synchronized boolean imageUpdate(final Image img,
114: final int infoflags, final int x, final int y,
115: final int width, final int height) {
116: if ((infoflags & ImageObserver.ALLBITS) == ImageObserver.ALLBITS) {
117: this .lock = false;
118: this .error = false;
119: notifyAll();
120: return false;
121: } else if ((infoflags & ImageObserver.ABORT) == ImageObserver.ABORT
122: || (infoflags & ImageObserver.ERROR) == ImageObserver.ERROR) {
123: this .lock = false;
124: this .error = true;
125: notifyAll();
126: return false;
127: }
128: //notifyAll();
129: return true;
130: }
131:
132: /**
133: * The workerthread. Simply draws the image to a BufferedImage's
134: * Graphics-Object and waits for the AWT to load the image.
135: */
136: public synchronized void waitImageLoaded() {
137:
138: if (this .lock == false) {
139: return;
140: }
141:
142: final BufferedImage img = new BufferedImage(1, 1,
143: BufferedImage.TYPE_INT_RGB);
144: final Graphics g = img.getGraphics();
145:
146: while (this .lock) {
147: if (g.drawImage(this .image, 0, 0, img.getWidth(this ), img
148: .getHeight(this ), this )) {
149: return;
150: }
151:
152: try {
153: wait(500);
154: } catch (InterruptedException e) {
155: Log
156: .info(
157: "WaitingImageObserver.waitImageLoaded(): InterruptedException thrown",
158: e);
159: }
160: }
161: }
162:
163: /**
164: * Clones this WaitingImageObserver.
165: *
166: * @return a clone.
167: *
168: * @throws CloneNotSupportedException this should never happen.
169: * @deprecated cloning may lock down the observer
170: */
171: public Object clone() throws CloneNotSupportedException {
172: return (WaitingImageObserver) super .clone();
173: }
174:
175: public boolean isLoadingComplete() {
176: return this .lock == false;
177: }
178:
179: /**
180: * Returns true if there is an error condition, and false otherwise.
181: *
182: * @return A boolean.
183: */
184: public boolean isError() {
185: return this.error;
186: }
187: }
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