net.sf.wdte.ui.views.util.ImageDescriptorRegistry.java Source code

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Here is the source code for net.sf.wdte.ui.views.util.ImageDescriptorRegistry.java

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/*
 * Copyright (c) 2004 Christopher Lenz and others
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     Christopher Lenz - initial implementation based on the internal Eclipse
 *                        class of the same name, defined in multiple packages
 * 
 * $Id: ImageDescriptorRegistry.java,v 1.1 2004/02/19 08:38:58 cell Exp $
 */

package net.sf.wdte.ui.views.util;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.widgets.Display;

/**
 * Registry that keeps a table of image descriptors and the images created from
 * those descriptors.
 */
public class ImageDescriptorRegistry {

    /**
     * Stores all registered image descriptors as keys, and the images created
     * from them as values.
     */
    private Map registry = new HashMap(10);

    // Constructors ------------------------------------------------------------

    /**
     * Creates a new image descriptor registry for the current or default
     * display, respectively.
     */
    public ImageDescriptorRegistry() {
        this(Display.getCurrent() != null ? Display.getCurrent() : Display.getDefault());
    }

    /**
     * Creates a new image descriptor registry for the given display. All images
     * managed by this registry will be disposed when the display gets disposed.
     * 
     * @param display the display the images managed by this registry are
     *        allocated for 
     */
    public ImageDescriptorRegistry(Display display) {
        display.disposeExec(new Runnable() {
            @Override
            public void run() {
                dispose();
            }
        });
    }

    /**
     * Returns the image assiciated with the given image descriptor.
     * 
     * @param descriptor the image descriptor for which the registry manages an
     *        image
     * @return the image associated with the image descriptor or <tt>null</tt>
     *         if the image descriptor can't create the requested image.
     */
    public Image get(ImageDescriptor descriptor) {
        if (descriptor == null) {
            descriptor = ImageDescriptor.getMissingImageDescriptor();
        }
        Image result = (Image) registry.get(descriptor);
        if (result == null) {
            result = descriptor.createImage();
            if (result != null) {
                registry.put(descriptor, result);
            }
        }
        return result;
    }

    /**
     * Disposes all images managed by this registry.
     */
    public void dispose() {
        for (Iterator i = registry.values().iterator(); i.hasNext();) {
            ((Image) i.next()).dispose();
        }
        registry.clear();
    }

}