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comparison dwt/graphics/Resource.d @ 0:380af2bdd8e5

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author Jacob Carlborg <doob@me.com> <jacob.carlborg@gmail.com>
date Sat, 09 Aug 2008 17:00:02 +0200
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1 /*******************************************************************************
2 * Copyright (c) 2000, 2005 IBM Corporation and others.
3 * All rights reserved. This program and the accompanying materials
4 * are made available under the terms of the Eclipse Public License v1.0
5 * which accompanies this distribution, and is available at
6 * http://www.eclipse.org/legal/epl-v10.html
7 *
8 * Contributors:
9 * IBM Corporation - initial API and implementation
10 *******************************************************************************/
11 module dwt.graphics.Resource;
12
13 import dwt.dwthelper.utils;
14
15 import dwt.DWT;
16
17 /**
18 * This class is the abstract superclass of all graphics resource objects.
19 * Resources created by the application must be disposed.
20 * <p>
21 * IMPORTANT: This class is intended to be subclassed <em>only</em>
22 * within the DWT implementation. However, it has not been marked
23 * final to allow those outside of the DWT development team to implement
24 * patched versions of the class in order to get around specific
25 * limitations in advance of when those limitations can be addressed
26 * by the team. Any class built using subclassing to access the internals
27 * of this class will likely fail to compile or run between releases and
28 * may be strongly platform specific. Subclassing should not be attempted
29 * without an intimate and detailed understanding of the workings of the
30 * hierarchy. No support is provided for user-written classes which are
31 * implemented as subclasses of this class.
32 * </p>
33 *
34 * @see #dispose
35 * @see #isDisposed
36 *
37 * @since 3.1
38 */
39 public abstract class Resource {
40
41 /**
42 * the device where this resource was created
43 */
44 Device device;
45
46 Resource() {
47 }
48
49 Resource(Device device) {
50 if (device is null) device = Device.getDevice();
51 if (device is null) DWT.error(DWT.ERROR_NULL_ARGUMENT);
52 this.device = device;
53 }
54
55 void destroy() {
56 }
57
58 /**
59 * Disposes of the operating system resources associated with
60 * this resource. Applications must dispose of all resources
61 * which they allocate.
62 */
63 public void dispose() {
64 if (device is null) return;
65 if (device.isDisposed()) return;
66 destroy();
67 if (device.tracking) device.dispose_Object(this);
68 device = null;
69 }
70
71 /**
72 * Returns the <code>Device</code> where this resource was
73 * created.
74 *
75 * @return <code>Device</code> the device of the receiver
76 *
77 * @since 3.2
78 */
79 public Device getDevice() {
80 Device device = this.device;
81 if (device is null || isDisposed ()) DWT.error (DWT.ERROR_GRAPHIC_DISPOSED);
82 return device;
83 }
84
85 void init() {
86 if (device.tracking) device.new_Object(this);
87 }
88
89 /**
90 * Returns <code>true</code> if the resource has been disposed,
91 * and <code>false</code> otherwise.
92 * <p>
93 * This method gets the dispose state for the resource.
94 * When a resource has been disposed, it is an error to
95 * invoke any other method using the resource.
96 *
97 * @return <code>true</code> when the resource is disposed and <code>false</code> otherwise
98 */
99 public abstract bool isDisposed();
100
101 }