descent.internal.ui.viewsupport.ImageDescriptorRegistry.java Source code

Introduction

Here is the source code for descent.internal.ui.viewsupport.ImageDescriptorRegistry.java

Source

/*******************************************************************************
 * Copyright (c) 2000, 2005 IBM Corporation and others.
 * 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:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package descent.internal.ui.viewsupport;

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

import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.widgets.Display;

import descent.internal.ui.util.SWTUtil;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.util.Assert;

/**
 * A registry that maps <code>ImageDescriptors</code> to <code>Image</code>.
 */
public class ImageDescriptorRegistry {

    private HashMap fRegistry = new HashMap(10);
    private Display fDisplay;

    /**
     * Creates a new image descriptor registry for the current or default display,
     * respectively.
     */
    public ImageDescriptorRegistry() {
        this(SWTUtil.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) {
        fDisplay = display;
        Assert.isNotNull(fDisplay);
        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 = (Image) fRegistry.get(descriptor);
        if (result != null)
            return result;

        Assert.isTrue(fDisplay == SWTUtil.getStandardDisplay(), "Allocating image for wrong display."); //$NON-NLS-1$
        result = descriptor.createImage();
        if (result != null)
            fRegistry.put(descriptor, result);
        return result;
    }

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

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