bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/ViewPluginAction.java

/*******************************************************************************
 * Copyright (c) 2000, 2017 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ui.internal;

import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.ui.IActionDelegate;
import org.eclipse.ui.IViewActionDelegate;
import org.eclipse.ui.IViewPart;
import org.eclipse.ui.WorkbenchException;

/**
 * This class extends regular plugin action with the additional requirement that
 * the delegate has to implement interface IViewActionDeelgate. This interface
 * has one additional method (init) whose purpose is to initialize the delegate
 * with the view part in which the action is intended to run.
 */
public final class ViewPluginAction extends PartPluginAction {
	private IViewPart viewPart;

	/**
	 * This class adds the requirement that action delegates loaded on demand
	 * implement IViewActionDelegate
	 */
	public ViewPluginAction(IConfigurationElement actionElement, IViewPart viewPart, String id, int style) {
		super(actionElement, id, style);
		this.viewPart = viewPart;
		registerSelectionListener(viewPart);
	}

	@Override
	protected IActionDelegate validateDelegate(Object obj) throws WorkbenchException {
		if (obj instanceof IViewActionDelegate) {
			return (IViewActionDelegate) obj;
		}
		throw new WorkbenchException("Action must implement IViewActionDelegate"); //$NON-NLS-1$
	}

	@Override
	protected void initDelegate() {
		super.initDelegate();
		((IViewActionDelegate) getDelegate()).init(viewPart);
	}

	/**
	 * Returns true if the view has been set The view may be null after the
	 * constructor is called and before the view is stored. We cannot create the
	 * delegate at that time.
	 */
	@Override
	public boolean isOkToCreateDelegate() {
		return super.isOkToCreateDelegate() && viewPart != null;
	}

	@Override
	public void dispose() {
		unregisterSelectionListener(viewPart);
		super.dispose();
	}
}