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1   /*
2    $Id: ValueHolder.java,v 1.1 2003/10/24 12:47:15 jstrachan Exp $
3   
4    Copyright 2003 (C) James Strachan and Bob Mcwhirter. All Rights Reserved.
5   
6    Redistribution and use of this software and associated documentation
7    ("Software"), with or without modification, are permitted provided
8    that the following conditions are met:
9   
10   1. Redistributions of source code must retain copyright
11      statements and notices.  Redistributions must also contain a
12      copy of this document.
13  
14   2. Redistributions in binary form must reproduce the
15      above copyright notice, this list of conditions and the
16      following disclaimer in the documentation and/or other
17      materials provided with the distribution.
18  
19   3. The name "groovy" must not be used to endorse or promote
20      products derived from this Software without prior written
21      permission of The Codehaus.  For written permission,
22      please contact info@codehaus.org.
23  
24   4. Products derived from this Software may not be called "groovy"
25      nor may "groovy" appear in their names without prior written
26      permission of The Codehaus. "groovy" is a registered
27      trademark of The Codehaus.
28  
29   5. Due credit should be given to The Codehaus -
30      http://groovy.codehaus.org/
31  
32   THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS
33   ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
34   NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
35   FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
36   THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
37   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
38   (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
39   SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
40   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
41   STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
42   ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
43   OF THE POSSIBILITY OF SUCH DAMAGE.
44  
45   */
46  package groovy.model;
47  
48  import java.beans.PropertyChangeListener;
49  import java.beans.PropertyChangeSupport;
50  
51  /***
52   * A simple ValueModle implementation which is a holder of an object value. 
53   * Used to share local variables with closures
54   * 
55   * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
56   * @version $Revision: 1.1 $
57   */
58  public class ValueHolder implements ValueModel {
59      private Object value;
60      private Class type;
61      private PropertyChangeSupport propertyChangeSupport;
62      private boolean editable = true;
63  
64      public ValueHolder() {
65          this(Object.class);
66      }
67      
68      public ValueHolder(Class type) {
69          this.type = type;
70      }
71      
72      public ValueHolder(Object value) {
73          this.value = value;
74          this.type = (value != null) ? value.getClass() : Object.class;
75      }
76      
77      /*** 
78       * Add a PropertyChangeListener to the listener list.
79       * @param l The listener to add.
80       */
81      public void addPropertyChangeListener(PropertyChangeListener listener) {
82          if ( propertyChangeSupport == null ) {
83              propertyChangeSupport = new PropertyChangeSupport(this);
84          }
85          propertyChangeSupport.addPropertyChangeListener(listener);
86      }
87      
88      /*** 
89       * Removes a PropertyChangeListener from the listener list.
90       * @param l The listener to remove.
91       */
92      public void removePropertyChangeListener(PropertyChangeListener listener) {
93          if ( propertyChangeSupport != null ) {
94              propertyChangeSupport.removePropertyChangeListener(listener);
95          }
96      }
97      
98  
99      public Object getValue() {
100         return value;
101     }
102 
103     public void setValue(Object value) {
104         Object oldValue = this.value;
105         this.value = value;
106         if ( propertyChangeSupport != null ) {
107             propertyChangeSupport.firePropertyChange("value", oldValue, value);
108         }
109     }
110 
111     public Class getType() {
112         return type;
113     }
114 
115     public boolean isEditable() {
116         return editable;
117     }
118     
119     public void setEditable(boolean editable) {
120         this.editable = editable;
121     }
122 
123 }