ErlideImageHelper.java

package org.erlide.common.ui;

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

import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.swt.graphics.Image;
import org.eclipse.ui.plugin.AbstractUIPlugin;
import org.eclipse.xtext.ui.IImageHelper;
import org.osgi.framework.BundleEvent;
import org.osgi.framework.SynchronousBundleListener;

import com.google.common.collect.Maps;
import com.google.inject.Inject;
import com.google.inject.Singleton;
import com.google.inject.name.Named;

/**
 * @author Sebastian Zarnekow
 */
@Singleton
public class ErlideImageHelper implements IImageHelper,
        SynchronousBundleListener {

    private final Map<ImageDescriptor, Image> registry = Maps
            .newHashMapWithExpectedSize(10);

    private AbstractUIPlugin plugin;

    @Inject(optional = true)
    @Named("org.eclipse.xtext.ui.PluginImageHelper.pathSuffix")
    private String pathSuffix = "icons/"; //$NON-NLS-1$

    @Inject(optional = true)
    @Named("org.eclipse.xtext.ui.PluginImageHelper.defaultImage")
    private String defaultImage = "default.gif"; //$NON-NLS-1$

    @Inject(optional = true)
    @Named("org.eclipse.xtext.ui.PluginImageHelper.notFound")
    private String notFound = "notFound.gif"; //$NON-NLS-1$

    public ErlideImageHelper() {
        plugin = CommonUiPlugin.getDefault();
    }

    /**
     * Returns the image associated with the given image descriptor.
     * 
     * @param descriptor
     *            the image descriptor for which the helper manages an image, or
     *            <code>null</code> for a missing image descriptor
     * @return the image associated with the image descriptor or
     *         <code>null</code> if the image descriptor can't create the
     *         requested image.
     */
    @Override
    public Image getImage(ImageDescriptor descriptor) {
        if (descriptor == null) {
            descriptor = ImageDescriptor.getMissingImageDescriptor();
        }

        Image result = registry.get(descriptor);
        if (result != null) {
            return result;
        }
        result = descriptor.createImage();
        if (result != null) {
            registry.put(descriptor, result);
        }
        return result;
    }

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

    @Inject
    public void hookBundleListener(final AbstractUIPlugin aplugin) {
        aplugin.getBundle().getBundleContext().addBundleListener(this);
    }

    @Override
    public Image getImage(final String imageName) {
        // System.out.println("-----------------------" + imageName);

        final String imgname = imageName == null ? defaultImage : imageName;
        if (imgname != null) {
            Image result = null;
            final URL imgUrl = getPlugin().getBundle().getEntry(
                    getPathSuffix() + imgname);
            if (imgUrl != null) {
                ImageDescriptor id = null;
                result = getPlugin().getImageRegistry().get(
                        imgUrl.toExternalForm());
                if (result == null) {
                    id = ImageDescriptor.createFromURL(imgUrl);
                    if (id != null) {
                        result = id.createImage();
                        getPlugin().getImageRegistry().put(
                                imgUrl.toExternalForm(), result);
                    }
                }
                // System.out.println(result);
                return result;
            }
            if (!imgname.equals(notFound)) {
                // System.out.println(notFound);
                return getImage(notFound);
            }
        }
        // System.out.println("null");
        return null;
    }

    public void setPathSuffix(final String pathSuffix) {
        this.pathSuffix = pathSuffix;
    }

    public String getPathSuffix() {
        return pathSuffix;
    }

    public void setPlugin(final AbstractUIPlugin plugin) {
        this.plugin = plugin;
    }

    public AbstractUIPlugin getPlugin() {
        return plugin;
    }

    public void setNotFound(final String notFound) {
        this.notFound = notFound;
    }

    public String getNotFound() {
        return notFound;
    }

    public String getDefaultImage() {
        return defaultImage;
    }

    public void setDefaultImage(final String defaultImage) {
        this.defaultImage = defaultImage;
    }

    @Override
    public void bundleChanged(final BundleEvent event) {
        if (event.getType() == BundleEvent.STOPPING
                && event.getBundle().getBundleId() == getPlugin().getBundle()
                        .getBundleId()) {
            dispose();
        }
    }

}