org.eclipse.emf.diffmerge.ui.viewers.ComparisonResourceManager.java Source code

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Here is the source code for org.eclipse.emf.diffmerge.ui.viewers.ComparisonResourceManager.java

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/**
 * <copyright>
 * 
 * Copyright (c) 2010-2012 Thales Global Services S.A.S.
 * 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:
 *    Thales Global Services S.A.S. - initial API and implementation
 * 
 * </copyright>
 */
package org.eclipse.emf.diffmerge.ui.viewers;

import java.util.HashMap;
import java.util.Map;

import org.eclipse.emf.diffmerge.ui.EMFDiffMergeUIPlugin;
import org.eclipse.emf.diffmerge.ui.EMFDiffMergeUIPlugin.ImageID;
import org.eclipse.emf.diffmerge.ui.util.DifferenceKind;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.viewers.DecorationOverlayIcon;
import org.eclipse.jface.viewers.IDecoration;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Image;
import org.eclipse.ui.services.IDisposable;

/**
 * A storage for SWT resources.
 * @author Olivier Constant
 */
public class ComparisonResourceManager implements IDisposable {

    /**
     * A trivial structure for identifying images with a predefined overlay
     */
    public static class ImageOverlay {
        /** The non-null original image */
        private Image _image;

        /** The non-null overlay */
        private ImageID _overlay;

        /**
         * Constructor
         * @param image_p a non-null image
         * @param overlay_p a non-null image ID
         */
        public ImageOverlay(Image image_p, ImageID overlay_p) {
            _image = image_p;
            _overlay = overlay_p;
        }

        /**
         * @see java.lang.Object#hashCode()
         */
        @Override
        public int hashCode() {
            return _image.hashCode() + _overlay.hashCode();
        }

        /**
         * @see java.lang.Object#equals(java.lang.Object)
         */
        @Override
        public boolean equals(Object object_p) {
            boolean result = false;
            if (object_p instanceof ImageOverlay) {
                ImageOverlay peer = (ImageOverlay) object_p;
                result = _image.equals(peer._image) && _overlay.equals(peer._overlay);
            }
            return result;
        }
    }

    /** The map from normal images to their disabled variant */
    private final Map<Image, Image> _normalToDisabled;

    /** The map from normal images to their variant with overlays */
    private final Map<ImageOverlay, Image> _normalToOverlay;

    /**
     * Constructor
     */
    public ComparisonResourceManager() {
        _normalToDisabled = new HashMap<Image, Image>();
        _normalToOverlay = new HashMap<ImageOverlay, Image>();
    }

    /**
     * Return a variant of the given image that corresponds to the given difference kind
     * @param image_p a potentially null image
     * @param kind_p a potentially null difference kind
     * @return a potentially null image
     */
    public Image adaptImage(Image image_p, DifferenceKind kind_p) {
        Image result = image_p;
        if (kind_p != null && image_p != null) {
            ImageID overlay = EMFDiffMergeUIPlugin.getDefault().getDifferenceOverlay(kind_p);
            result = getOverlayVersion(image_p, overlay);
        }
        return result;
    }

    /**
     * Dispose the receiver
     */
    public void dispose() {
        for (Image disabled : _normalToDisabled.values())
            disabled.dispose();
        _normalToDisabled.clear();
        for (Image overlay : _normalToOverlay.values())
            overlay.dispose();
        _normalToOverlay.clear();
    }

    /**
     * Return an image which is the disabled variant of the given one
     * @param image_p a non-null image
     * @return a non-null image
     */
    public Image getDisabledVersion(Image image_p) {
        Image result = _normalToDisabled.get(image_p);
        if (result == null) {
            result = new Image(image_p.getDevice(), image_p, SWT.IMAGE_DISABLE);
            _normalToDisabled.put(image_p, result);
        }
        return result;
    }

    /**
     * Return an image which is based on the given one with the given overlay
     * @param image_p a non-null image
     * @param overlay_p a potentially null image ID
     * @return a non-null image
     */
    public Image getOverlayVersion(Image image_p, ImageID overlay_p) {
        Image result;
        if (overlay_p == null) {
            result = image_p;
        } else {
            ImageOverlay io = new ImageOverlay(image_p, overlay_p);
            result = _normalToOverlay.get(io);
            if (result == null) {
                ImageDescriptor overlayDescriptor = EMFDiffMergeUIPlugin.getDefault().getImageDescriptor(overlay_p);
                DecorationOverlayIcon icon = new DecorationOverlayIcon(image_p, overlayDescriptor,
                        IDecoration.BOTTOM_RIGHT);
                result = icon.createImage(image_p.getDevice());
                _normalToOverlay.put(io, result);
            }
        }
        return result;
    }

}