001    /*
002     * $Id: NewInstanceMetaMethod.java 4550 2006-12-21 22:22:40Z blackdrag $
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:
009     *  1. Redistributions of source code must retain copyright statements and
010     * notices. Redistributions must also contain a copy of this document.
011     *  2. Redistributions in binary form must reproduce the above copyright
012     * notice, this list of conditions and the following disclaimer in the
013     * documentation and/or other materials provided with the distribution.
014     *  3. The name "groovy" must not be used to endorse or promote products
015     * derived from this Software without prior written permission of The Codehaus.
016     * For written permission, please contact info@codehaus.org.
017     *  4. Products derived from this Software may not be called "groovy" nor may
018     * "groovy" appear in their names without prior written permission of The
019     * Codehaus. "groovy" is a registered trademark of The Codehaus.
020     *  5. Due credit should be given to The Codehaus - http://groovy.codehaus.org/
021     *
022     * THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS ``AS IS'' AND ANY
023     * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
024     * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
025     * DISCLAIMED. IN NO EVENT SHALL THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR
026     * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
027     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
028     * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
029     * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
030     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
031     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
032     * DAMAGE.
033     *
034     */
035    package org.codehaus.groovy.runtime;
036    
037    import groovy.lang.MetaMethod;
038    
039    import java.lang.reflect.Modifier;
040    
041    /**
042     * A MetaMethod implementation where the underlying method is really a static
043     * helper method on some class but it appears to be an instance method on a class.
044     * 
045     * This implementation is used to add new methods to the JDK writing them as normal
046     * static methods with the first parameter being the class on which the method is added.
047     * 
048     * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
049     * @version $Revision: 4550 $
050     */
051    public class NewInstanceMetaMethod extends MetaMethod {
052    
053        private static final Class[] EMPTY_TYPE_ARRAY = {};
054        
055        private MetaMethod metaMethod;
056        private Class[] logicalParameterTypes;
057    
058        
059        public NewInstanceMetaMethod(MetaMethod metaMethod) {
060            super(metaMethod);
061            this.metaMethod = metaMethod;
062            init();
063        }
064        
065        public NewInstanceMetaMethod(String name, Class declaringClass, Class[] parameterTypes, Class returnType, int modifiers) {
066            super(name, declaringClass, parameterTypes, returnType, modifiers);
067            this.metaMethod = new MetaMethod(name, declaringClass, parameterTypes,returnType, modifiers);
068            init();
069        }
070        
071        private void init() {
072            Class[] realParameterTypes = metaMethod.getParameterTypes();
073            int size = realParameterTypes!=null ? realParameterTypes.length : 0;
074            if (size <= 1) {
075                logicalParameterTypes = EMPTY_TYPE_ARRAY;
076            } else {
077                logicalParameterTypes = new Class[--size];
078                System.arraycopy(realParameterTypes, 1, logicalParameterTypes, 0, size);
079            }
080        }
081        
082        public Class getDeclaringClass() {
083            return getBytecodeParameterTypes()[0];
084        }
085    
086        public boolean isStatic() {
087            return false;
088        }
089    
090        public int getModifiers() {
091            // lets clear the static bit
092            return super.getModifiers() ^ Modifier.STATIC;
093        }
094    
095        public Class[] getParameterTypes() {
096            return logicalParameterTypes;
097        }
098    
099        public Class[] getBytecodeParameterTypes() {
100            return super.getParameterTypes();
101        }
102    
103        public Object invoke(Object object, Object[] arguments)  {
104            // we need to cheat using the type
105            int size = arguments.length;
106            Object[] newArguments = new Object[size + 1];
107            newArguments[0] = object;
108            System.arraycopy(arguments, 0, newArguments, 1, size);
109            return metaMethod.invoke(null, newArguments);
110        }
111        
112        public Class getOwnerClass() {
113            return getBytecodeParameterTypes()[0];
114        }
115    }