content: /*
   * Copyright (c) 1996, 2003, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  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 JDK1.1
   */
  
  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.
       * @exception  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 a String representation of this EventObject.
       */
      public String toString() {
          return getClass().getName() + "[source=" + source + "]";
      }
  }
  