/*******************************************************************************
* Copyright (c) 2004, 2005 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.html.ui.internal.editor;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.resource.ImageRegistry;
import org.eclipse.swt.graphics.Image;
import org.eclipse.ui.plugin.AbstractUIPlugin;
import org.eclipse.wst.html.ui.internal.HTMLUIPlugin;
import java.util.HashMap;
/**
* Helper class to handle images provided by this plug-in.
*/
public class HTMLEditorPluginImageHelper {
private final String PLUGINID = HTMLUIPlugin.ID;
private static HTMLEditorPluginImageHelper instance = null;
// save a descriptor for each image
private HashMap fImageDescRegistry = null;
/**
* Gets the instance.
*
* @return Returns a HTMLEditorPluginImageHelper
*/
public synchronized static HTMLEditorPluginImageHelper getInstance() {
if (instance == null)
instance = new HTMLEditorPluginImageHelper();
return instance;
}
/**
* Retrieves the image associated with resource from the image registry. If the image cannot be
* retrieved, attempt to find and load the image at the location specified in resource.
*
* @param resource the image to retrieve
* @return Image the image associated with resource or null if one could not be found
*/
public Image getImage(String resource) {
Image image = getImageRegistry().get(resource);
if (image == null) {
// create an image
image = createImage(resource);
}
return image;
}
/**
* Retrieves the image descriptor associated with resource from the image descriptor registry. If
* the image descriptor cannot be retrieved, attempt to find and load the image descriptor at the
* location specified in resource.
*
* @param resource the image descriptor to retrieve
* @return ImageDescriptor the image descriptor assocated with resource or the default "missing"
* image descriptor if one could not be found
*/
public ImageDescriptor getImageDescriptor(String resource) {
ImageDescriptor imageDescriptor = null;
Object o = getImageDescriptorRegistry().get(resource);
if (o == null) {
//create a descriptor
imageDescriptor = createImageDescriptor(resource);
} else {
imageDescriptor = (ImageDescriptor) o;
}
return imageDescriptor;
}
/**
* Returns the image descriptor registry for this plugin.
*
* @return HashMap - image descriptor registry for this plugin
*/
private HashMap getImageDescriptorRegistry() {
if (fImageDescRegistry == null)
fImageDescRegistry = new HashMap();
return fImageDescRegistry;
}
/**
* Returns the image registry for this plugin.
*
* @return ImageRegistry - image registry for this plugin
*/
private ImageRegistry getImageRegistry() {
return HTMLUIPlugin.getInstance().getImageRegistry();
}
/**
* Creates an image from the given resource and adds the image to the image registry.
*
* @param resource
* @return Image
*/
private Image createImage(String resource) {
ImageDescriptor desc = getImageDescriptor(resource);
Image image = null;
if (desc != null) {
image = desc.createImage();
// dont add the missing image descriptor image to the image registry
if (!desc.equals(ImageDescriptor.getMissingImageDescriptor()))
getImageRegistry().put(resource, image);
}
return image;
}
/**
* Creates an image descriptor from the given imageFilePath and adds the image descriptor to the
* image descriptor registry. If an image descriptor could not be created, the default "missing"
* image descriptor is returned but not added to the image descriptor registry.
*
* @param imageFilePath
* @return ImageDescriptor image descriptor for imageFilePath or default "missing" image
* descriptor if resource could not be found
*/
private ImageDescriptor createImageDescriptor(String imageFilePath) {
ImageDescriptor imageDescriptor = AbstractUIPlugin.imageDescriptorFromPlugin(PLUGINID,
imageFilePath);
if (imageDescriptor != null) {
getImageDescriptorRegistry().put(imageFilePath, imageDescriptor);
} else {
imageDescriptor = ImageDescriptor.getMissingImageDescriptor();
}
return imageDescriptor;
}
}