SWTResourceUtil


1   /*******************************************************************************
2    * Copyright (c) 2000, 2006 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  
12  package org.eclipse.ui.internal.util;
13  
14  import java.util.Hashtable  ;
15  import java.util.Iterator  ;
16  import java.util.Map  ;
17  
18  import org.eclipse.swt.graphics.Color;
19  import org.eclipse.swt.graphics.Font;
20  import org.eclipse.swt.graphics.Image;
21  
22  /**
23   * SWTResourceUtil is a class that holds onto Colors, Fonts and Images and
24   * disposes them on shutdown.
25   */
26  public class SWTResourceUtil {
27  
28      /**
29       * The cache of images that have been dispensed by this provider. Maps
30       * ImageDescriptor->Image. Caches are all static to avoid creating extra
31       * system resources for very common images, font and colors.
32       */
33      private static Map   imageTable = new Hashtable  (40);
34  
35      /**
36       * The cache of colors that have been dispensed by this provider. Maps
37       * RGB->Color.
38       */
39      private static Map   colorTable = new Hashtable  (7);
40  
41      /**
42       * The cache of fonts that have been dispensed by this provider. Maps
43       * FontData->Font.
44       */
45      private static Map   fontTable = new Hashtable  (7);
46  
47      /**
48       * Disposes of all allocated images, colors and fonts when shutting down the
49       * plug-in.
50       */
51      public static final void shutdown() {
52          if (imageTable != null) {
53              for (Iterator   i = imageTable.values().iterator(); i.hasNext();) {
54                  ((Image) i.next()).dispose();
55              }
56              imageTable = null;
57          }
58          if (colorTable != null) {
59              for (Iterator   i = colorTable.values().iterator(); i.hasNext();) {
60                  ((Color) i.next()).dispose();
61              }
62              colorTable = null;
63          }
64          if (fontTable != null) {
65              for (Iterator   i = fontTable.values().iterator(); i.hasNext();) {
66                  ((Font) i.next()).dispose();
67              }
68              fontTable = null;
69          }
70      }
71  
72      /**
73       * Get the Map of RGBs to Colors.
74       * @return Returns the colorTable.
75       */
76      public static Map   getColorTable() {
77          return colorTable;
78      }
79  
80      /**
81       * Return the map of FontDatas to Fonts. 
82       * @return Returns the fontTable.
83       */
84      public static Map   getFontTable() {
85          return fontTable;
86      }
87  
88      /**
89       * Return the map of ImageDescriptors to Images.
90       * @return Returns the imageTable.
91       */
92      public static Map   getImageTable() {
93          return imageTable;
94      }
95  }
96
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