001    /*
002     $Id: Expando.java,v 1.6 2005/07/16 20:00:26 phk 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.ParameterArray;
049    import groovy.lang.Closure;
050    import groovy.lang.GroovyObjectSupport;
051    import groovy.lang.GroovyRuntimeException;
052    import groovy.lang.MetaExpandoProperty;
053    
054    import java.util.HashMap;
055    import java.util.Map;
056    import java.util.Map.Entry;
057    import java.util.List;
058    import java.util.ArrayList;
059    import java.util.Iterator;
060    
061    
062    /**
063     * Represents a dynamically expandable bean.
064     * 
065     * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
066     * @author Hein Meling
067     * @author Pilho Kim
068     * @version $Revision: 1.6 $
069     */
070    public class Expando extends GroovyObjectSupport {
071    
072        private Map expandoProperties;
073    
074        public Expando() {
075        }
076    
077        public Expando(Map expandoProperties) {
078            this.expandoProperties = expandoProperties;
079        }
080    
081        /**
082         * @return the dynamically expanded properties
083         */
084        public Map getExpandoProperties() {
085            if (expandoProperties == null) {
086                expandoProperties = createMap();
087            }
088            return expandoProperties;
089        }
090    
091        public List getProperties() {
092            // run through all our current properties and create MetaProperty objects
093            List ret = new ArrayList();
094            Iterator itr = getExpandoProperties().entrySet().iterator();
095            while(itr.hasNext()) {
096                Entry entry = (Entry) itr.next();
097                ret.add(new MetaExpandoProperty(entry));
098            }
099                    
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    }