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1   /*
2    $Id: Expando.java,v 1.6 2005/07/16 20:00:26 phk 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.util;
47  
48  import groovy.lang.ParameterArray;
49  import groovy.lang.Closure;
50  import groovy.lang.GroovyObjectSupport;
51  import groovy.lang.GroovyRuntimeException;
52  import groovy.lang.MetaExpandoProperty;
53  
54  import java.util.HashMap;
55  import java.util.Map;
56  import java.util.Map.Entry;
57  import java.util.List;
58  import java.util.ArrayList;
59  import java.util.Iterator;
60  
61  
62  /***
63   * Represents a dynamically expandable bean.
64   * 
65   * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
66   * @author Hein Meling
67   * @author Pilho Kim
68   * @version $Revision: 1.6 $
69   */
70  public class Expando extends GroovyObjectSupport {
71  
72      private Map expandoProperties;
73  
74      public Expando() {
75      }
76  
77      public Expando(Map expandoProperties) {
78          this.expandoProperties = expandoProperties;
79      }
80  
81      /***
82       * @return the dynamically expanded properties
83       */
84      public Map getExpandoProperties() {
85          if (expandoProperties == null) {
86              expandoProperties = createMap();
87          }
88          return expandoProperties;
89      }
90  
91      public List getProperties() {
92          // run through all our current properties and create MetaProperty objects
93          List ret = new ArrayList();
94          Iterator itr = getExpandoProperties().entrySet().iterator();
95          while(itr.hasNext()) {
96              Entry entry = (Entry) itr.next();
97              ret.add(new MetaExpandoProperty(entry));
98          }
99  		
100         return ret;
101     }
102 
103     public Object getProperty(String property) {
104         try {
105             return super.getProperty(property);
106         }
107         catch (GroovyRuntimeException e) {
108             return getExpandoProperties().get(property);
109         }
110     }
111 
112     public void setProperty(String property, Object newValue) {
113         try {
114             super.setProperty(property, newValue);
115         }
116         catch (GroovyRuntimeException e) {
117             getExpandoProperties().put(property, newValue);
118         }
119     }
120 
121     public Object invokeMethod(String name, Object args) {
122         try {
123             return super.invokeMethod(name, args);
124         }
125         catch (GroovyRuntimeException e) {
126             // br should get a "native" property match first. getProperty includes such fall-back logic
127             Object value = this.getProperty(name);
128             if (value instanceof Closure) {
129                 Closure closure = (Closure) value;
130                 closure.setDelegate(this);
131                 return closure.call(new ParameterArray(args));
132             }
133             else {
134                 throw e;
135             }
136         }
137         
138     }
139     
140     /***
141      * This allows toString to be overridden by a closure <i>field</i> method attached
142      * to the expando object.
143      * 
144      * @see java.lang.Object#toString()
145      */
146      public String toString() {
147         Object method = getExpandoProperties().get("toString");
148         if (method != null && method instanceof Closure) {
149             // invoke overridden toString closure method
150             Closure closure = (Closure) method;
151             closure.setDelegate(this);
152             return closure.call().toString();
153         } else {
154             return expandoProperties.toString();
155         }
156      }
157 
158     /***
159      * This allows equals to be overridden by a closure <i>field</i> method attached
160      * to the expando object.
161      *
162      * @see java.lang.Object#equals(java.lang.Object)
163      */
164     public boolean equals(Object obj) {
165         Object method = getExpandoProperties().get("equals");
166         if (method != null && method instanceof Closure) {
167             // invoke overridden equals closure method
168             Closure closure = (Closure) method;
169             closure.setDelegate(this);
170             Boolean ret = (Boolean) closure.call(obj);
171             return ret.booleanValue();
172         } else {
173             return super.equals(obj);
174         }
175     }
176 
177     /***
178      * This allows hashCode to be overridden by a closure <i>field</i> method attached
179      * to the expando object.
180      *
181      * @see java.lang.Object#hashCode()
182      */
183     public int hashCode() {
184         Object method = getExpandoProperties().get("hashCode");
185         if (method != null && method instanceof Closure) {
186             // invoke overridden hashCode closure method
187             Closure closure = (Closure) method;
188             closure.setDelegate(this);
189             Integer ret = (Integer) closure.call();
190             return ret.intValue();
191         } else {
192             return super.hashCode();
193         }
194     }
195 
196     /***
197      * Factory method to create a new Map used to store the expando properties map
198      * @return a newly created Map implementation
199      */
200     protected Map createMap() {
201         return new HashMap();
202     }
203 
204 }