org.eclipse.wst.jsdt.debug.internal.rhino.ui.RhinoImageRegistry.java Source code

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Here is the source code for org.eclipse.wst.jsdt.debug.internal.rhino.ui.RhinoImageRegistry.java

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/*******************************************************************************
 * Copyright (c) 2010 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.jsdt.debug.internal.rhino.ui;

import java.net.URL;

import org.eclipse.core.runtime.FileLocator;
import org.eclipse.core.runtime.Path;
import org.eclipse.core.runtime.Platform;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.resource.ImageRegistry;
import org.eclipse.swt.graphics.Image;
import org.eclipse.ui.PlatformUI;
import org.osgi.framework.Bundle;

/**
 * Image registry for shared images used in JavaScript Debug UI
 * 
 * @since 1.0
 */
public final class RhinoImageRegistry {

    /** 
     * The image registry containing <code>Image</code>s and <code>ImageDescriptor</code>s.
     */
    private static ImageRegistry imageRegistry;
    private static ImageDescriptorRegistry descRegistry;

    private static String ICONS_PATH = "$nl$/icons/"; //$NON-NLS-1$

    /**
     * Icon paths
     */
    final static String ELCL = ICONS_PATH + "elcl16/"; //enabled - size 16x16 //$NON-NLS-1$
    final static String OVR = ICONS_PATH + "ovr16/"; //overlays //$NON-NLS-1$
    final static String DLCL = ICONS_PATH + "dlcl16/"; //disabled icons //$NON-NLS-1$

    /**
     * Declare all images
     */
    private static void declareImages() {
        //ELCL
        declareRegistryImage(ISharedImages.IMG_SCRIPT, ELCL + "script.gif"); //$NON-NLS-1$
        declareRegistryImage(ISharedImages.IMG_RHINO, ELCL + "rhino.gif"); //$NON-NLS-1$
        declareRegistryImage(ISharedImages.IMG_MAIN_TAB, ELCL + "main_tab.gif"); //$NON-NLS-1$
        declareRegistryImage(ISharedImages.IMG_LIBRARY, ELCL + "library.gif"); //$NON-NLS-1$
    }

    /**
     * Declare an Image in the registry table.
     * @param key    The key to use when registering the image
     * @param path   The path where the image can be found. This path is relative to where
     *            this plugin class is found (i.e. typically the packages directory)
     */
    private final static void declareRegistryImage(String key, String path) {
        ImageDescriptor desc = ImageDescriptor.getMissingImageDescriptor();
        Bundle bundle = Platform.getBundle(RhinoUIPlugin.PLUGIN_ID);
        URL url = null;
        if (bundle != null) {
            url = FileLocator.find(bundle, new Path(path), null);
            if (url != null) {
                desc = ImageDescriptor.createFromURL(url);
            }
        }
        imageRegistry.put(key, desc);
    }

    /**
     * Returns the shared image for the given key or <code>null</code>.
     * @param key
     * @return the requested image or <code>null</code> if the image does not exist
     */
    public static Image getSharedImage(String key) {
        if (imageRegistry == null) {
            initializeImageRegistry();
        }
        return imageRegistry.get(key);
    }

    /**
     * Initializes the registry if it has not been already
     * @return the initialized registry
     */
    private synchronized static ImageRegistry initializeImageRegistry() {
        if (imageRegistry == null) {
            imageRegistry = new ImageRegistry(PlatformUI.getWorkbench().getDisplay());
            declareImages();
        }
        return imageRegistry;
    }

    /**
     * Creates the image from the descriptor and caches it for proper disposal
     * @param descriptor
     * @return
     */
    public static Image getImage(ImageDescriptor descriptor) {
        if (descRegistry == null) {
            descRegistry = new ImageDescriptorRegistry();
        }
        return descRegistry.get(descriptor);
    }

    /**
     * Disposes the image registry
     */
    public static void dispose() {
        if (imageRegistry != null) {
            imageRegistry.dispose();
        }
        if (descRegistry != null) {
            descRegistry.dispose();
        }
    }

    /**
     * Constructor
     */
    private RhinoImageRegistry() {
        // no direct instantiation
    }
}