docs/teaching/exercises/answers/Answer4d.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 figures.FigureElement;
import figures.Group;
import figures.Point;
import java.awt.Rectangle;

aspect Answer4d {
    private Rectangle Group.cache = null;
    private Group Point.enclosingGroup = null;

    before(Point p, Group g):
        execution(void add(FigureElement)) && args(p) && target(g) {
        p.enclosingGroup = g;
    }

    Rectangle around(Group g):
            execution(Rectangle Group.getBounds()) && this(g) {
        if (g.cache == null) {
            g.cache = proceed(g);
        }
        return g.cache;
    }

    before(Point p): set(* Point.*) && target(p) {
        if (p.enclosingGroup != null) {
            p.enclosingGroup.cache = null;
        }
    }
}