001    /*
002     $Id: Reference.java,v 1.2 2004/03/09 06:59:51 jstrachan 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.lang;
047    
048    import org.codehaus.groovy.runtime.InvokerHelper;
049    
050    /**
051     * Represents a reference to a value
052     * 
053     * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
054     * @version $Revision: 1.2 $
055     */
056    public class Reference extends GroovyObjectSupport {
057    
058        private Object value;
059    
060        public Reference() {
061        }
062    
063        public Reference(Object value) {
064            this.value = value;
065        }
066    
067        public Object getProperty(String property) {
068            Object value = get();
069            if (value != null) {
070                return InvokerHelper.getProperty(value, property);
071            }
072            return super.getProperty(property);
073        }
074    
075        public void setProperty(String property, Object newValue) {
076            Object value = get();
077            if (value != null) {
078                InvokerHelper.setProperty(value, property, newValue);
079            }
080            else {
081                super.setProperty(property, newValue);
082            }
083        }
084    
085        public Object invokeMethod(String name, Object args) {
086            Object value = get();
087            if (value != null) {
088                try {
089                    return InvokerHelper.invokeMethod(value, name, args);
090                }
091                catch (Exception e) {
092                    return super.invokeMethod(name, args);
093                }
094            }
095            else {
096                return super.invokeMethod(name, args);
097            }
098        }
099    
100        public Object get() {
101            return value;
102        }
103    
104        public void set(Object value) {
105            this.value = value;
106        }
107    }