io.usethesource.impulse.runtime.ImageDescriptorRegistry.java Source code

Introduction

Here is the source code for io.usethesource.impulse.runtime.ImageDescriptorRegistry.java

Source

/*******************************************************************************
* Copyright (c) 2007 IBM Corporation.
* 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:
*    Robert Fuhrer (rfuhrer@watson.ibm.com) - initial API and implementation
*******************************************************************************/

package io.usethesource.impulse.runtime;

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;

import io.usethesource.impulse.ui.SWTUtil;

/**
 * A registry that maps <code>ImageDescriptors</code> to <code>Image</code>.
 */
public class ImageDescriptorRegistry {
    private HashMap<ImageDescriptor, Image> fRegistry = new HashMap<ImageDescriptor, Image>(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 (Image image : fRegistry.values()) {
            image.dispose();
        }
        fRegistry.clear();
    }

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