001    /*
002     $Id: Expando.java,v 1.10 2005/10/03 18:07:36 tug Exp $
003    
004     Copyright 2003 (C) James Strachan and Bob Mcwhirter. All Rights Reserved.
005    
006     Redistribution and use of this software and associated documentation
007     ("Software"), with or without modification, are permitted provided
008     that the following conditions are met:
009    
010     1. Redistributions of source code must retain copyright
011        statements and notices.  Redistributions must also contain a
012        copy of this document.
013    
014     2. Redistributions in binary form must reproduce the
015        above copyright notice, this list of conditions and the
016        following disclaimer in the documentation and/or other
017        materials provided with the distribution.
018    
019     3. The name "groovy" must not be used to endorse or promote
020        products derived from this Software without prior written
021        permission of The Codehaus.  For written permission,
022        please contact info@codehaus.org.
023    
024     4. Products derived from this Software may not be called "groovy"
025        nor may "groovy" appear in their names without prior written
026        permission of The Codehaus. "groovy" is a registered
027        trademark of The Codehaus.
028    
029     5. Due credit should be given to The Codehaus -
030        http://groovy.codehaus.org/
031    
032     THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS
033     ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
034     NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
035     FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
036     THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
037     INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
038     (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
039     SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
040     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
041     STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
042     ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
043     OF THE POSSIBILITY OF SUCH DAMAGE.
044    
045     */
046    package groovy.util;
047    
048    import groovy.lang.Closure;
049    import groovy.lang.GroovyObjectSupport;
050    import groovy.lang.GroovyRuntimeException;
051    import groovy.lang.MetaExpandoProperty;
052    
053    import java.util.HashMap;
054    import java.util.Map;
055    import java.util.Map.Entry;
056    import java.util.List;
057    import java.util.ArrayList;
058    import java.util.Iterator;
059    
060    
061    /**
062     * Represents a dynamically expandable bean.
063     * 
064     * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
065     * @author Hein Meling
066     * @author Pilho Kim
067     * @version $Revision: 1.10 $
068     */
069    public class Expando extends GroovyObjectSupport {
070    
071        private Map expandoProperties;
072    
073        public Expando() {
074        }
075    
076        public Expando(Map expandoProperties) {
077            this.expandoProperties = expandoProperties;
078        }
079    
080        /**
081         * @return the dynamically expanded properties
082         */
083        public Map getProperties() {
084            if (expandoProperties == null) {
085                expandoProperties = createMap();
086            }
087            return expandoProperties;
088        }
089    
090        public List getMetaPropertyValues() {
091            // run through all our current properties and create MetaProperty objects
092            List ret = new ArrayList();
093            Iterator itr = getProperties().entrySet().iterator();
094            while(itr.hasNext()) {
095                Entry entry = (Entry) itr.next();
096                ret.add(new MetaExpandoProperty(entry));
097            }
098                    
099            return ret;
100        }
101    
102        public Object getProperty(String property) {
103            try {
104                return super.getProperty(property);
105            }
106            catch (GroovyRuntimeException e) {
107                return getProperties().get(property);
108            }
109        }
110    
111        public void setProperty(String property, Object newValue) {
112            try {
113                super.setProperty(property, newValue);
114            }
115            catch (GroovyRuntimeException e) {
116                getProperties().put(property, newValue);
117            }
118        }
119    
120        public Object invokeMethod(String name, Object args) {
121            try {
122                return super.invokeMethod(name, args);
123            }
124            catch (GroovyRuntimeException e) {
125                // br should get a "native" property match first. getProperty includes such fall-back logic
126                Object value = this.getProperty(name);
127                if (value instanceof Closure) {
128                    Closure closure = (Closure) value;
129                    closure.setDelegate(this);
130                    return closure.call((Object[]) args);
131                }
132                else {
133                    throw e;
134                }
135            }
136            
137        }
138        
139        /**
140         * This allows toString to be overridden by a closure <i>field</i> method attached
141         * to the expando object.
142         * 
143         * @see java.lang.Object#toString()
144         */
145         public String toString() {
146            Object method = getProperties().get("toString");
147            if (method != null && method instanceof Closure) {
148                // invoke overridden toString closure method
149                Closure closure = (Closure) method;
150                closure.setDelegate(this);
151                return closure.call().toString();
152            } else {
153                return expandoProperties.toString();
154            }
155         }
156    
157        /**
158         * This allows equals to be overridden by a closure <i>field</i> method attached
159         * to the expando object.
160         *
161         * @see java.lang.Object#equals(java.lang.Object)
162         */
163        public boolean equals(Object obj) {
164            Object method = getProperties().get("equals");
165            if (method != null && method instanceof Closure) {
166                // invoke overridden equals closure method
167                Closure closure = (Closure) method;
168                closure.setDelegate(this);
169                Boolean ret = (Boolean) closure.call(obj);
170                return ret.booleanValue();
171            } else {
172                return super.equals(obj);
173            }
174        }
175    
176        /**
177         * This allows hashCode to be overridden by a closure <i>field</i> method attached
178         * to the expando object.
179         *
180         * @see java.lang.Object#hashCode()
181         */
182        public int hashCode() {
183            Object method = getProperties().get("hashCode");
184            if (method != null && method instanceof Closure) {
185                // invoke overridden hashCode closure method
186                Closure closure = (Closure) method;
187                closure.setDelegate(this);
188                Integer ret = (Integer) closure.call();
189                return ret.intValue();
190            } else {
191                return super.hashCode();
192            }
193        }
194    
195        /**
196         * Factory method to create a new Map used to store the expando properties map
197         * @return a newly created Map implementation
198         */
199        protected Map createMap() {
200            return new HashMap();
201        }
202    
203    }