org.eclipse.vex.ui/src/org/eclipse/vex/ui/internal/Icon.java

/*******************************************************************************
 * Copyright (c) 2009 Holger Voormann 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:
 *     Holger Voormann - initial API and implementation
 *******************************************************************************/
package org.eclipse.vex.ui.internal;

import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.resource.ImageRegistry;
import org.eclipse.swt.graphics.Image;
import org.eclipse.ui.plugin.AbstractUIPlugin;

/**
 * This enumeration contains the icons used by this plug-in that are very frequently used and so need to be globally
 * shared within the plug-in. The icons are lazy loaded and disposed when the plug-in/bundle is stopped.
 */
public enum Icon {

	/** 16x16 icon: XML element (resource). */
	ELEMENT("icons/element_obj.gif"), //$NON-NLS-1$

	/** 16x16 icon: Convert (action). */
	CONVERT("icons/convert.gif"); //$NON-NLS-1$

	private final String iconFilePath;

	private Icon(final String iconFilePath) {
		this.iconFilePath = iconFilePath;
	}

	/**
	 * @param icon
	 *            the icon to be returned as {@link Image}
	 * @return the specified icon as {@link Image}
	 */
	public static Image get(final Icon icon) {
		final ImageRegistry registry = VexPlugin.getDefault().getImageRegistry();
		Image value = registry.get(icon.iconFilePath);
		if (value == null) {
			final ImageDescriptor imageDescriptor = createImageDescriptor(icon.iconFilePath);
			registry.put(icon.iconFilePath, imageDescriptor);
			value = registry.get(icon.iconFilePath);
		}
		return value;
	}

	private static ImageDescriptor createImageDescriptor(final String filePath) {
		final ImageDescriptor descriptor = AbstractUIPlugin.imageDescriptorFromPlugin(VexPlugin.ID, filePath);

		Assert.isNotNull(descriptor, "Image file not found: " + filePath); //$NON-NLS-1$
		return descriptor;
	}

}