001: /*
002: * This file is part of the Echo Web Application Framework (hereinafter "Echo").
003: * Copyright (C) 2002-2005 NextApp, Inc.
004: *
005: * Version: MPL 1.1/GPL 2.0/LGPL 2.1
006: *
007: * The contents of this file are subject to the Mozilla Public License Version
008: * 1.1 (the "License"); you may not use this file except in compliance with
009: * the License. You may obtain a copy of the License at
010: * http://www.mozilla.org/MPL/
011: *
012: * Software distributed under the License is distributed on an "AS IS" basis,
013: * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
014: * for the specific language governing rights and limitations under the
015: * License.
016: *
017: * Alternatively, the contents of this file may be used under the terms of
018: * either the GNU General Public License Version 2 or later (the "GPL"), or
019: * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
020: * in which case the provisions of the GPL or the LGPL are applicable instead
021: * of those above. If you wish to allow use of your version of this file only
022: * under the terms of either the GPL or the LGPL, and not to allow others to
023: * use your version of this file under the terms of the MPL, indicate your
024: * decision by deleting the provisions above and replace them with the notice
025: * and other provisions required by the GPL or the LGPL. If you do not delete
026: * the provisions above, a recipient may use your version of this file under
027: * the terms of any one of the MPL, the GPL or the LGPL.
028: */
029:
030: package nextapp.echo2.app;
031:
032: import java.awt.Image;
033: import java.awt.Toolkit;
034: import java.awt.image.ColorModel;
035: import java.awt.image.ImageObserver;
036: import java.awt.image.MemoryImageSource;
037: import java.awt.image.PixelGrabber;
038: import java.io.IOException;
039: import java.io.ObjectInputStream;
040: import java.io.ObjectOutputStream;
041:
042: /**
043: * An ImageReference describing an image which may be rendered from
044: * a <code>java.awt.Image</code>.
045: * Note that the JVM running the Echo Application Container will require
046: * access to a graphics context for the Java AWT to function.
047: */
048: public class AwtImageReference implements ImageReference {
049:
050: private transient Image image;
051: private String id;
052:
053: /**
054: * Default constructor for use only when a class is derived from
055: * <code>AwtImageReference</code> and the
056: * <code>getImage()</code> method is overridden.
057: */
058: public AwtImageReference() {
059: this (null);
060: }
061:
062: /**
063: * Creates an <code>AwtImageReference</code> to the specified
064: * <code>java.awt.Image</code>.
065: * Note that changes to the underlying image will not necessarily be
066: * reflected on the client unless the image-containing property of the
067: * target component is update.
068: *
069: * @param image the <code>java.awt.Image </code>to be displayed.
070: */
071: public AwtImageReference(Image image) {
072: super ();
073: this .image = image;
074: id = ApplicationInstance.generateSystemId();
075: }
076:
077: /**
078: * @see java.lang.Object#equals(java.lang.Object)
079: */
080: public boolean equals(Object o) {
081: if (!(o instanceof AwtImageReference)) {
082: return false;
083: }
084: AwtImageReference that = (AwtImageReference) o;
085: if (!(this .image == that.image || (this .image != null && this .image
086: .equals(that.image)))) {
087: return false;
088: }
089: return true;
090: }
091:
092: /**
093: * @see nextapp.echo2.app.ImageReference#getHeight()
094: */
095: public Extent getHeight() {
096: if (image == null) {
097: return null;
098: }
099: int height = image.getHeight(null);
100: if (height > 0) {
101: return new Extent(height, Extent.PX);
102: } else {
103: return null;
104: }
105: }
106:
107: /**
108: * @see nextapp.echo2.app.RenderIdSupport#getRenderId()
109: */
110: public String getRenderId() {
111: return id;
112: }
113:
114: /**
115: * Retrieves the image. Calls to this method will be minimized such that
116: * applications may extend this class and override this method such that
117: * images are created only when they are needed, thereby reducing memory
118: * usage at the cost of increased processor workload.
119: * You should also override the <code>getWidth()</code> and
120: * <code>getHeight()</code> methods.
121: */
122: public Image getImage() {
123: return image;
124: }
125:
126: /**
127: * @see nextapp.echo2.app.ImageReference#getWidth()
128: */
129: public Extent getWidth() {
130: if (image == null) {
131: return null;
132: }
133: int width = image.getWidth(null);
134: if (width > 0) {
135: return new Extent(width, Extent.PX);
136: } else {
137: return null;
138: }
139: }
140:
141: /**
142: * @see java.io.Serializable
143: */
144: private void readObject(ObjectInputStream in) throws IOException,
145: ClassNotFoundException {
146: in.defaultReadObject();
147:
148: int width = in.readInt();
149: int height = in.readInt();
150: int[] pixels = (int[]) in.readObject();
151:
152: if (pixels != null) {
153: Toolkit toolkit = Toolkit.getDefaultToolkit();
154: ColorModel colorModel = ColorModel.getRGBdefault();
155: image = toolkit.createImage(new MemoryImageSource(width,
156: height, colorModel, pixels, 0, width));
157: }
158: }
159:
160: /**
161: * @see java.io.Serializable
162: */
163: private void writeObject(ObjectOutputStream out) throws IOException {
164: out.defaultWriteObject();
165:
166: int width = image.getWidth(null);
167: int height = image.getHeight(null);
168:
169: out.writeInt(width);
170: out.writeInt(height);
171:
172: if (image == null) {
173: out.writeObject(null);
174: } else {
175: int[] pixels = new int[width * height];
176: try {
177: PixelGrabber pg = new PixelGrabber(image, 0, 0, width,
178: height, pixels, 0, width);
179: pg.grabPixels();
180: if ((pg.getStatus() & ImageObserver.ABORT) != 0) {
181: throw new IOException(
182: "Unable to serialize java.awt.image: PixelGrabber aborted.");
183: }
184: } catch (InterruptedException ex) {
185: throw new IOException(
186: "Unable to serialize java.awt.Image: PixelGrabber interrupted.");
187: }
188: out.writeObject(pixels);
189: }
190: }
191: }
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