/*******************************************************************************
 * Copyright (c) 2011 University of Mannheim: Chair for Software Engineering
 * 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:
 *    Ralph Gerbig - initial API and implementation and initial documentation
 *******************************************************************************/
package de.uni_mannheim.informatik.swt.common;

import java.util.HashSet;

import org.eclipse.emf.ecore.EClassifier;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.ocl.ParserException;
import org.eclipse.ocl.ecore.Constraint;
import org.eclipse.ocl.ecore.OCL;
import org.eclipse.ocl.expressions.OCLExpression;

public class OCLHelper {

	/**
	 * Helper for convenient one line call of OCL expressions
	 * 
	 * @param context The eObject which is the context
	 * @param expression expression to execute
	 *
	 * @return value of evaluated expression 
	 *
	 * @throws ParserException 
	 */
	public static Object execute(Object context, String expression) throws ParserException{
		
		EObject eObject = (EObject)context;
		
		return execute(context, eObject.eClass(), expression);
	}
	
	/**
	 * Helper for convenient one line call of OCL expressions
	 * 
	 * @param context The eObject which is the context
	 * @param contextLiteral xxxPackage.Literals.xxx
	 * @param expression expression to execute
	 *
	 * @return value of evaluated expression 
	 *
	 * @throws ParserException 
	 */
	public static Object execute(Object context, EClassifier contextLiteral, String expression) throws ParserException{
		OCL ocl = OCL
				.newInstance();

		org.eclipse.ocl.helper.OCLHelper<EClassifier, ?, ?, Constraint> helper = ocl.createOCLHelper();
		helper.setContext(contextLiteral);

		OCLExpression<EClassifier> q = helper.createQuery(expression);
		return ocl.evaluate(context, q);
	}
}