content: /*
   * Copyright (c) 1996, 2011, 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.beans;
  
  import java.util.EventObject;
  
  /**
   * A "PropertyChange" event gets delivered whenever a bean changes a "bound"
   * or "constrained" property.  A PropertyChangeEvent object is sent as an
   * argument to the PropertyChangeListener and VetoableChangeListener methods.
   * <P>
   * Normally PropertyChangeEvents are accompanied by the name and the old
   * and new value of the changed property.  If the new value is a primitive
   * type (such as int or boolean) it must be wrapped as the
   * corresponding java.lang.* Object type (such as Integer or Boolean).
   * <P>
   * Null values may be provided for the old and the new values if their
   * true values are not known.
   * <P>
   * An event source may send a null object as the name to indicate that an
   * arbitrary set of if its properties have changed.  In this case the
   * old and new values should also be null.
   */
  public class PropertyChangeEvent extends EventObject {
      private static final long serialVersionUID = 7042693688939648123L;
  
      /**
       * Constructs a new {@code PropertyChangeEvent}.
       *
       * @param source        the bean that fired the event
       * @param propertyName  the programmatic name of the property that was changed
       * @param oldValue      the old value of the property
       * @param newValue      the new value of the property
       *
       * @throws IllegalArgumentException if {@code source} is {@code null}
       */
      public PropertyChangeEvent(Object source, String propertyName,
                                 Object oldValue, Object newValue) {
          super(source);
          this.propertyName = propertyName;
          this.newValue = newValue;
          this.oldValue = oldValue;
      }
  
      /**
       * Gets the programmatic name of the property that was changed.
       *
       * @return  The programmatic name of the property that was changed.
       *          May be null if multiple properties have changed.
       */
      public String getPropertyName() {
          return propertyName;
      }
  
      /**
       * Gets the new value for the property, expressed as an Object.
       *
       * @return  The new value for the property, expressed as an Object.
       *          May be null if multiple properties have changed.
       */
      public Object getNewValue() {
          return newValue;
      }
  
      /**
       * Gets the old value for the property, expressed as an Object.
       *
       * @return  The old value for the property, expressed as an Object.
       *          May be null if multiple properties have changed.
       */
      public Object getOldValue() {
          return oldValue;
      }
  
      /**
       * Sets the propagationId object for the event.
       *
       * @param propagationId  The propagationId object for the event.
       */
      public void setPropagationId(Object propagationId) {
          this.propagationId = propagationId;
      }
  
      /**
       * The "propagationId" field is reserved for future use.  In Beans 1.0
       * the sole requirement is that if a listener catches a PropertyChangeEvent
       * and then fires a PropertyChangeEvent of its own, then it should
       * make sure that it propagates the propagationId field from its
       * incoming event to its outgoing event.
       *
       * @return the propagationId object associated with a bound/constrained
       *          property update.
       */
      public Object getPropagationId() {
          return propagationId;
      }
  
      /**
       * name of the property that changed.  May be null, if not known.
       * @serial
       */
      private String propertyName;
  
      /**
       * New value for property.  May be null if not known.
       * @serial
       */
      private Object newValue;
  
      /**
       * Previous value for property.  May be null if not known.
       * @serial
       */
      private Object oldValue;
  
      /**
       * Propagation ID.  May be null.
       * @serial
       * @see #getPropagationId
       */
      private Object propagationId;
  
      /**
       * Returns a string representation of the object.
       *
       * @return a string representation of the object
       *
       * @since 1.7
       */
      public String toString() {
          StringBuilder sb = new StringBuilder(getClass().getName());
          sb.append("[propertyName=").append(getPropertyName());
          appendTo(sb);
          sb.append("; oldValue=").append(getOldValue());
          sb.append("; newValue=").append(getNewValue());
          sb.append("; propagationId=").append(getPropagationId());
          sb.append("; source=").append(getSource());
          return sb.append("]").toString();
      }
  
      void appendTo(StringBuilder sb) {
      }
  }
  