001    /*
002     * $Id: ClosureListener.java 2121 2005-04-12 16:38:42Z 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 that the
008     * following conditions are met: 1. Redistributions of source code must retain
009     * copyright statements and notices. Redistributions must also contain a copy
010     * of this document. 2. Redistributions in binary form must reproduce the above
011     * copyright notice, this list of conditions and the following disclaimer in
012     * the documentation and/or other materials provided with the distribution. 3.
013     * The name "groovy" must not be used to endorse or promote products derived
014     * from this Software without prior written permission of The Codehaus. For
015     * written permission, please contact info@codehaus.org. 4. Products derived
016     * from this Software may not be called "groovy" nor may "groovy" appear in
017     * their names without prior written permission of The Codehaus. "groovy" is a
018     * registered trademark of The Codehaus. 5. Due credit should be given to The
019     * Codehaus - http://groovy.codehaus.org/
020     * 
021     * THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS ``AS IS'' AND ANY
022     * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
023     * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
024     * DISCLAIMED. IN NO EVENT SHALL THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR
025     * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
026     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
027     * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
028     * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
029     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
030     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
031     * DAMAGE.
032     *  
033     */
034    package org.codehaus.groovy.runtime;
035    
036    import groovy.lang.Closure;
037    
038    import java.lang.reflect.InvocationHandler;
039    import java.lang.reflect.Method;
040    
041    /**
042     * Represents a method on an object using a closure which can be invoked at any
043     * time
044     * 
045     * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
046     * @version $Revision: 2121 $
047     */
048    public class ClosureListener implements InvocationHandler {
049    
050        private String listenerMethodName;
051        private Closure closure;
052    
053        public ClosureListener(String listenerMethodName, Closure closure) {
054            this.listenerMethodName = listenerMethodName;
055            this.closure = closure;
056        }
057    
058        public Object invoke(Object object, Method method, Object[] arguments) throws Throwable {
059            if (listenerMethodName.equals(method.getName())) {
060                /** @todo hack! */
061                closure.call(arguments[0]);
062                return null;
063            }
064    
065            // lets try call this object
066            String name = method.getName();
067            if (name.equals("equals")) {
068                return object == arguments[0] ? Boolean.TRUE : Boolean.FALSE;
069            }
070            else if (name.equals("hashCode")) {
071                return new Integer(hashCode());
072            }
073            else if (name.equals("toString")) {
074                return super.toString() + "[listener:" + listenerMethodName + "]";
075            }
076    
077            /*
078                     * int paramCount = method.getParameterTypes().length;
079                     * 
080                     * System.out.println("Now calling method: " + method);
081                     * 
082                     * Method[] methods = Object.class.getMethods(); for (int i = 0; i
083                     * < methods.length; i++ ) { Method aMethod = methods[i]; if
084                     * (name.equals(aMethod.getName()) &&
085                     * aMethod.getParameterTypes().length == paramCount) { return
086                     * aMethod.invoke(object, arguments); } }
087                     */
088            return null;
089        }
090    
091    }