bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/actions/RetargetActionWithDefault.java

/*******************************************************************************
 * Copyright (c) 2004 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 - Initial API and implementation
 *******************************************************************************/
package org.eclipse.ui.internal.ide.actions;

import org.eclipse.jface.action.IAction;
import org.eclipse.ui.actions.RetargetAction;

/**
 * A specialization of RetargetAction that allows for specification of a default
 * handler when the active part does not supply one.  Enablement of this
 * action is based on enablement of the handler, or enablement of the default
 * handler if no explicit handler is available.
 * 
 * @since 3.1
 */
public class RetargetActionWithDefault extends RetargetAction {

	private IAction defaultHandler;

	/**
	 * Constructs a RetargetActionWithDefault with the given action id and text.
	 * 
	 * @param actionID the retargetable action id
	 * @param text the action's text, or <code>null</code> if there is no text
	 */
	public RetargetActionWithDefault(String actionID, String text) {
		super(actionID, text);
	}

	/* (non-Javadoc)
	 * Method declared on RetargetAction.
	 */
	protected void setActionHandler(IAction newHandler) {
		super.setActionHandler(newHandler);
		// Only set the default handler after clearing the old handler above.
		// This triggers enablement updating on the default handler which 
		// might be needed since the active part has changed.
		if (newHandler == null)
			super.setActionHandler(defaultHandler);
	}

	/**
	 * Sets the default handler for this action.
	 * @param handler An action handler, or <code>null</code>
	 */
	public void setDefaultHandler(IAction handler) {
		this.defaultHandler = handler;
		if (getActionHandler() == null && handler != null)
			super.setActionHandler(handler);
	}
}