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 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
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 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing,
 *  software distributed under the License is distributed on an
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 *  KIND, either express or implied.  See the License for the
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package org.apache.cayenne.graph;

import org.apache.cayenne.event.CayenneEvent;

/**
 * An event indicating a change in the object graph. A change is expressed as a GraphDiff,
 * so the easiest way to process the event is the following:
 * 
 * <pre>
 *    GraphChangeHandler handler = ..;
 *    event.getDiff().apply(handler);
 * </pre>
 * 
 * @since 1.2
 * @author Andrus Adamchik
 */
public class GraphEvent extends CayenneEvent {

    protected GraphDiff diff;

    public GraphEvent(Object source, GraphDiff diff) {
        this(source, source, diff);
    }

    public GraphEvent(Object source, Object postedBy, GraphDiff diff) {
        super(source, postedBy, null);
        this.diff = diff;
    }

    public GraphDiff getDiff() {
        return diff;
    }
}
