/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.debug.ui;


import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.debug.core.DebugException;
import org.eclipse.debug.core.model.IThread;
import org.eclipse.debug.ui.DebugUITools;
import org.eclipse.jdt.debug.core.IJavaStackFrame;
import org.eclipse.jdt.internal.debug.ui.snippeteditor.ScrapbookLauncher;
import org.eclipse.ui.IActionFilter;

public class JavaWatchExpressionActionFilter implements IActionFilter {

	public boolean testAttribute(Object target, String name, String value) {
		if (target instanceof JavaWatchExpression) {
			if (name.equals("ReevaluateWatchExpressionActionFilter") && value.equals("availableJavaDebugTarget")) { //$NON-NLS-1$ //$NON-NLS-2$
				return availableJavaDebugTarget();
			}
		}
		return false;
	}
	
	private boolean availableJavaDebugTarget() {
		IAdaptable context = DebugUITools.getDebugContext();
		if (context instanceof IThread) {
			try {
				context = ((IThread)context).getTopStackFrame();
			} catch (DebugException e) {
				JDIDebugUIPlugin.log(e);
			}
		}
		if (context != null) {
			IJavaStackFrame frame = (IJavaStackFrame) context.getAdapter(IJavaStackFrame.class);
			if (frame != null) {
				if (frame.getLaunch().getAttribute(ScrapbookLauncher.SCRAPBOOK_LAUNCH) == null) {
					return true;
				}
			}
		}
		return false;
	}

}