org.eclipse.wst.server.discovery.internal.ImageResource.java Source code

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Here is the source code for org.eclipse.wst.server.discovery.internal.ImageResource.java

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/*******************************************************************************
 * Copyright (c) 2008 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 org.eclipse.wst.server.discovery.internal;

import java.net.URL;
import java.util.HashMap;
import java.util.Map;

import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.resource.ImageRegistry;

import org.eclipse.swt.graphics.Image;
import org.eclipse.ui.PlatformUI;

/**
 * Utility class to handle image resources.
 */
public class ImageResource {
    // the image registry
    private static ImageRegistry imageRegistry;

    // map of image descriptors since these
    // will be lost by the image registry
    private static Map<String, ImageDescriptor> imageDescriptors;

    // base urls for images
    private static URL ICON_BASE_URL;

    static {
        try {
            String pathSuffix = "icons/";
            ICON_BASE_URL = Activator.getDefault().getBundle().getEntry(pathSuffix);
        } catch (Exception e) {
            Trace.trace(Trace.SEVERE, "Could not set icon base URL", e);
        }
    }

    private static final String URL_OBJ = "obj16/";

    private static final String URL_WIZBAN = "wizban/";

    // --- constants for images ---

    public static final String IMG_WIZARD = "wizard";
    public static final String IMG_EXTENSION = "extension";

    /**
     * Cannot construct an ImageResource. Use static methods only.
     */
    private ImageResource() {
        // do nothing
    }

    /**
     * Dispose of element images that were created.
     */
    protected static void dispose() {
        // do nothing
    }

    /**
     * Return the image with the given key.
     *
     * @param key a key
     * @return an image
     */
    public static Image getImage(String key) {
        if (imageRegistry == null)
            initializeImageRegistry();
        Image image = imageRegistry.get(key);
        if (image == null) {
            imageRegistry.put(key, ImageDescriptor.getMissingImageDescriptor());
            image = imageRegistry.get(key);
        }
        return image;
    }

    /**
     * Return the image descriptor with the given key.
     *
     * @param key a key
     * @return an image descriptor
     */
    public static ImageDescriptor getImageDescriptor(String key) {
        if (imageRegistry == null)
            initializeImageRegistry();
        ImageDescriptor id = imageDescriptors.get(key);
        if (id != null)
            return id;

        return ImageDescriptor.getMissingImageDescriptor();
    }

    /**
     * Initialize the image resources.
     */
    protected static void initializeImageRegistry() {
        imageRegistry = new ImageRegistry();
        imageDescriptors = new HashMap<String, ImageDescriptor>();

        registerImage(IMG_WIZARD, URL_WIZBAN + "install_wiz.gif");
        registerImage(IMG_EXTENSION, URL_OBJ + "iu_obj.gif");

        PlatformUI.getWorkbench().getProgressService().registerIconForFamily(getImageDescriptor(IMG_EXTENSION),
                Activator.JOB_FAMILY);
    }

    /**
     * Register an image with the registry.
     *
     * @param key a key
     * @param partialURL a partial URL
     */
    private static void registerImage(String key, String partialURL) {
        try {
            ImageDescriptor id = ImageDescriptor.createFromURL(new URL(ICON_BASE_URL, partialURL));
            imageRegistry.put(key, id);
            imageDescriptors.put(key, id);
        } catch (Exception e) {
            Trace.trace(Trace.SEVERE, "Error registering image " + key + " from " + partialURL, e);
        }
    }
}