docs/teaching/exercises/answers/Answer3d.java


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/* *******************************************************************
 * Copyright (c) 2002 Palo Alto Research Center, Incorporated (PARC).
 * 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:
 *     PARC     initial implementation
 * ******************************************************************/

package answers;

import support.Log;

import figures.*;

aspect Answer3d {

    boolean Point.inGroup = false;

    before(Point p): execution(void Group.add(FigureElement)) && args(p) {
	if (p.inGroup) {
	    throw new IllegalStateException();
	} else {
	    p.inGroup = true;
	}
    }
}