/*
 *  Licensed to the Apache Software Foundation (ASF) under one 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 with
 *  the License.  You may obtain a copy of the License at
 *
 *     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 "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package java.util;


import java.io.Serializable;

/**
 * {@code EventObject}s represent events. Typically applications subclass this class to
 * add event specific information.
 *
 * @see EventListener
 */
public class EventObject implements Serializable {

    private static final long serialVersionUID = 5516075349620653480L;

    /**
     * The event source.
     */
    protected transient Object source;

    /**
     * Constructs a new instance of this class.
     *
     * @param source
     *            the object which fired the event.
     */
    public EventObject(Object source) {
        if (source != null) {
            this.source = source;
        } else {
            throw new IllegalArgumentException();
        }
    }

    /**
     * Returns the event source.
     *
     * @return the object which fired the event.
     */
    public Object getSource() {
        return source;
    }

    /**
     * Returns the string representation of this {@code EventObject}.
     *
     * @return the string representation of this {@code EventObject}.
     */
    @Override
    public String toString() {
        return getClass().getName() + "[source=" + source + ']';
    }
}
