Migrated source code from Simantics SVN

[simantics/platform.git] / bundles / org.simantics.utils.ui / src / org / simantics / utils / ui / gfx / ImageCache.java

diff --git a/bundles/org.simantics.utils.ui/src/org/simantics/utils/ui/gfx/ImageCache.java b/bundles/org.simantics.utils.ui/src/org/simantics/utils/ui/gfx/ImageCache.java
new file mode 100644 (file)
index 0000000..f194f5f
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+++ b/bundles/org.simantics.utils.ui/src/org/simantics/utils/ui/gfx/ImageCache.java
@@ -0,0 +1,106 @@
+/*******************************************************************************\r
+ * Copyright (c) 2007, 2010 Association for Decentralized Information Management\r
+ * in Industry THTH ry.\r
+ * All rights reserved. This program and the accompanying materials\r
+ * are made available under the terms of the Eclipse Public License v1.0\r
+ * which accompanies this distribution, and is available at\r
+ * http://www.eclipse.org/legal/epl-v10.html\r
+ *\r
+ * Contributors:\r
+ *     VTT Technical Research Centre of Finland - initial API and implementation\r
+ *******************************************************************************/\r
+package org.simantics.utils.ui.gfx;\r
+\r
+import java.util.concurrent.ConcurrentHashMap;\r
+import java.util.concurrent.ConcurrentMap;\r
+\r
+import org.eclipse.jface.resource.ImageDescriptor;\r
+import org.eclipse.jface.resource.LocalResourceManager;\r
+import org.eclipse.jface.resource.ResourceManager;\r
+import org.eclipse.swt.graphics.Image;\r
+\r
+/**\r
+ * ImageCache caches SWT images and does clean dispose.<br>\r
+ * Based on "eclipse - building commercial-quality plug-ins" book's chapter\r
+ * 7.7's example.<br>\r
+ * \r
+ * @author Marko Luukkainen\r
+ * \r
+ * @deprecated Please avoid using this class if at all possible. From a resource\r
+ *             management point-of-view this class does not fit well into a\r
+ *             dynamic OSGi component world. Instead, use JFace\r
+ *             {@link ResourceManager} and particularly\r
+ *             {@link LocalResourceManager}. You can create one in your local\r
+ *             context (a view, editor, bundle activator, etc.) with\r
+ *             <code>new LocalResourceManager(JFaceResources.getResources())</code>\r
+ *             . Remember to dispose your LocalResourceManager when its owner is\r
+ *             disposed. Images can be loaded using\r
+ *             {@link LocalResourceManager#createImage(ImageDescriptor)}.\r
+ * \r
+ */\r
+public class ImageCache {\r
+\r
+    /** A singleton cache instance */\r
+    private static final ImageCache                      imageCache = new ImageCache();\r
+\r
+    /** Descriptor to image mapping */\r
+    private final ConcurrentMap<ImageDescriptor, Image>  images     = new ConcurrentHashMap<ImageDescriptor, Image>();\r
+\r
+    private final ConcurrentMap<ImageDescriptor, Object> locks      = new ConcurrentHashMap<ImageDescriptor, Object>();\r
+\r
+    /**\r
+     * Retrieves and caches the specified image.\r
+     * \r
+     * @param imageDescriptor the ImageDescriptor of the Image\r
+     * @return Image valid image or <code>null</code>if the image could not be\r
+     *         created\r
+     */\r
+    public Image getImage(ImageDescriptor imageDescriptor) {\r
+        if (imageDescriptor == null)\r
+            return null;\r
+\r
+        Image image = images.get(imageDescriptor);\r
+        if (image != null)\r
+            return image;\r
+\r
+        Object newLock = new Object();\r
+        Object loadLock = locks.putIfAbsent(imageDescriptor, newLock);\r
+        if (loadLock == null)\r
+            loadLock = newLock;\r
+\r
+        // Localized locking, don't lock the whole class while actually loading the image.\r
+        synchronized (loadLock) {\r
+            image = images.get(imageDescriptor);\r
+            if (image == null) {\r
+                boolean returnError = false;\r
+                image = imageDescriptor.createImage(returnError);\r
+                if (image != null) {\r
+                    images.put(imageDescriptor, image);\r
+                }\r
+            }\r
+        }\r
+\r
+        locks.remove(imageDescriptor, loadLock);\r
+\r
+        return image;\r
+    }\r
+\r
+    public void dispose() {\r
+        // Do not synchronize while disposing image resources\r
+        Image[] imgs = null;\r
+        synchronized (images) {\r
+            imgs = images.values().toArray(new Image[images.size()]);\r
+            images.clear();\r
+        }\r
+        locks.clear();\r
+\r
+        for (Image img : imgs) {\r
+            img.dispose();\r
+        }\r
+    }\r
+\r
+    public static ImageCache getInstance() {\r
+        return imageCache;\r
+    }\r
+\r
+}\r