/*
 * Copyright (c) 1996, 2003, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package java.util;

/**
 * <p>
 * The root class from which all event state objects shall be derived.
 * <p>
 * All Events are constructed with a reference to the object, the "source",
 * that is logically deemed to be the object upon which the Event in question
 * initially occurred upon.
 *
 * @since 1.1
 */

public class EventObject implements java.io.Serializable {

 private static final long serialVersionUID = 5516075349620653480L;

 /**
 * The object on which the Event initially occurred.
 */
 protected transient Object source;

 /**
 * Constructs a prototypical Event.
 *
 * @param source the object on which the Event initially occurred
 * @throws IllegalArgumentException if source is null
 */
 public EventObject(Object source) {
 if (source == null)
 throw new IllegalArgumentException("null source");

 this.source = source;
 }

 /**
 * The object on which the Event initially occurred.
 *
 * @return the object on which the Event initially occurred
 */
 public Object getSource() {
 return source;
 }

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