/*******************************************************************************
 * Copyright (c) 2000, 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
 *     Pawel Piech - Bug 75183
 *******************************************************************************/
package org.eclipse.debug.internal.ui.actions;

 
import org.eclipse.debug.core.DebugEvent;
import org.eclipse.debug.core.DebugPlugin;
import org.eclipse.debug.core.IDebugEventSetListener;
import org.eclipse.jface.action.IAction;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.IActionDelegate2;
import org.eclipse.ui.IViewPart;
import org.eclipse.ui.IWorkbenchWindow;

public abstract class AbstractListenerActionDelegate extends AbstractDebugActionDelegate implements IDebugEventSetListener, IActionDelegate2 {

    private boolean fDisposed = false;
    
	/**
	 * @see org.eclipse.ui.IWorkbenchWindowActionDelegate#dispose()
	 * @see org.eclipse.ui.IActionDelegate2#dispose()
	 */
	public synchronized void dispose() {
		super.dispose();
		DebugPlugin.getDefault().removeDebugEventListener(this);
        fDisposed = true;
	}
	
	/**
	 * @see IDebugEventSetListener#handleDebugEvents(DebugEvent[])
	 */
	public void handleDebugEvents(final DebugEvent[] events) {
		if (getWindow() == null || getAction() == null) {
			return;
		}
		Shell shell= getWindow().getShell();
		if (shell == null || shell.isDisposed()) {
			return;
		}
        synchronized (this) {
            if (fDisposed) {
                return;
            }
        }
		for (int i = 0; i < events.length; i++) {
			if (events[i].getSource() != null) {
				doHandleDebugEvent(events[i]);
			}
		}		
	}
	
	/**
	 * Default implementation to update on specific debug events.
	 * Subclasses should override to handle events differently.
	 */
	protected void doHandleDebugEvent(DebugEvent event) {
		switch (event.getKind()) {
			case DebugEvent.TERMINATE :
				update(getAction(), getSelection());
				break;
			case DebugEvent.RESUME :
				if (!event.isEvaluation() || !((event.getDetail() & DebugEvent.EVALUATION_IMPLICIT) != 0)) {
					update(getAction(), getSelection());
				}
				break;
			case DebugEvent.SUSPEND :
				// Update on suspend events (even for evaluations), in case the user changed
				// the selection during an implicit evaluation.
				update(getAction(), getSelection());
				break;
			case DebugEvent.CHANGE :
				// Implementations can use this event for debugger state
				// changes other than just suspend/resume.  This may or 
				// may not affect the enable state of run/suspend/step
				// actions.
				update(getAction(), getSelection());
				break;
		}
	}		

	/**
	 * @see IWorkbenchWindowActionDelegate#init(IWorkbenchWindow)
	 */
	public void init(IWorkbenchWindow window){
		super.init(window);
		DebugPlugin.getDefault().addDebugEventListener(this);
	}

	/**
	 * @see IViewActionDelegate#init(IViewPart)
	 */
	public void init(IViewPart view) {
		super.init(view);
		DebugPlugin.getDefault().addDebugEventListener(this);
		setWindow(view.getViewSite().getWorkbenchWindow());
	}

	/**
	 * @see org.eclipse.ui.IActionDelegate2#init(org.eclipse.jface.action.IAction)
	 */
	public void init(IAction action) {
	}

	/**
	 * @see org.eclipse.ui.IActionDelegate2#runWithEvent(org.eclipse.jface.action.IAction, org.eclipse.swt.widgets.Event)
	 */
	public void runWithEvent(IAction action, Event event) {
		run(action);
	}
}
