001    /*
002     $Id: ClassExtender.java 259 2003-11-04 12:00:48Z jstrachan $
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 org.codehaus.groovy.runtime;
047    
048    import groovy.lang.Closure;
049    
050    import java.util.HashMap;
051    import java.util.Map;
052    
053    
054    /**
055     * A helper class used by the runtime to allow Groovy classes to be extended at runtime
056     * 
057     * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
058     * @version $Revision: 259 $
059     */
060    public class ClassExtender {
061        private Map variables;
062        private Map methods;
063    
064        public synchronized Object get(String name) {
065            if (variables != null) {
066                return variables.get(name);
067            }
068            return null;
069        }
070    
071        public synchronized void set(String name, Object value) {
072            if (variables == null) {
073                variables = createMap();
074            }
075            variables.put(name, value);
076        }
077    
078        public synchronized void remove(String name) {
079            if (variables != null) {
080                variables.remove(name);
081            }
082        }
083    
084        public void call(String name, Object params) {
085            Closure closure = null;
086            synchronized (this) {
087                if (methods != null) {
088                    closure = (Closure) methods.get(name);
089                }
090            }
091            if (closure != null) {
092                closure.call(params);
093            }
094            /*
095            else {
096                throw DoesNotUnderstandException();
097            }
098            */
099        }
100    
101        public synchronized void addMethod(String name, Closure closure) {
102            if (methods == null) {
103                methods = createMap();
104            }
105            methods.put(name, methods);
106        }
107    
108        public synchronized void removeMethod(String name) {
109            if (methods != null) {
110                methods.remove(name);
111            }
112        }
113    
114        protected Map createMap() {
115            return new HashMap();
116        }
117    }