org.springframework.ide.eclipse.ui.ImageDescriptorRegistry.java Source code

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Here is the source code for org.springframework.ide.eclipse.ui.ImageDescriptorRegistry.java

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/*******************************************************************************
 * Copyright (c) 2006, 2007 Spring IDE Developers
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Spring IDE Developers - initial API and implementation
 *******************************************************************************/
package org.springframework.ide.eclipse.ui;

import java.util.HashMap;

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

/**
 * A registry that maps {@link ImageDescriptor}s to {@link Image}.
 * @author Torsten Juergeleit
 * @author Christian Dupuis
 */
public class ImageDescriptorRegistry {

    private HashMap<ImageDescriptor, Image> registry = new HashMap<ImageDescriptor, Image>(10);
    private Display display;

    /**
     * Creates a new image descriptor registry for the current or default
     * display, respectively.
     */
    public ImageDescriptorRegistry() {
        this(SpringUIUtils.getStandardDisplay());
    }

    /**
     * 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) {
        Assert.isNotNull(display);
        this.display = display;
        hookDisplay();
    }

    /**
     * Returns the image associated 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
     *         <code>null</code> if the image descriptor can't create the
     *         requested image.
     */
    public Image get(ImageDescriptor descriptor) {
        if (descriptor == null) {
            descriptor = ImageDescriptor.getMissingImageDescriptor();
        }
        Image result = registry.get(descriptor);
        if (result != null) {
            return result;
        }
        Assert.isTrue(display == SpringUIUtils.getStandardDisplay(),
                SpringUIMessages.ImageDescriptorRegistry_wrongDisplay);
        result = descriptor.createImage();
        if (result != null) {
            registry.put(descriptor, result);
        }
        return result;
    }

    /**
     * Disposes all images managed by this registry.
     */
    public void dispose() {
        for (Image image : registry.values()) {
            image.dispose();
        }
        registry.clear();
    }

    private void hookDisplay() {
        display.disposeExec(new Runnable() {
            public void run() {
                dispose();
            }
        });
    }
}