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Java > Open Source Codes > org > codehaus > groovy > runtime > NewInstanceMetaMethod


1 /*
2  * $Id: NewInstanceMetaMethod.java,v 1.1 2004/03/25 00:35:19 glaforge Exp $
3  *
4  * Copyright 2003 (C) James Strachan and Bob Mcwhirter. All Rights Reserved.
5  *
6  * Redistribution and use of this software and associated documentation
7  * ("Software"), with or without modification, are permitted provided that the
8  * following conditions are met:
9  * 1. Redistributions of source code must retain copyright statements and
10  * notices. Redistributions must also contain a copy of this document.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  * notice, this list of conditions and the following disclaimer in the
13  * documentation and/or other materials provided with the distribution.
14  * 3. The name "groovy" must not be used to endorse or promote products
15  * derived from this Software without prior written permission of The Codehaus.
16  * For written permission, please contact info@codehaus.org.
17  * 4. Products derived from this Software may not be called "groovy" nor may
18  * "groovy" appear in their names without prior written permission of The
19  * Codehaus. "groovy" is a registered trademark of The Codehaus.
20  * 5. Due credit should be given to The Codehaus - http://groovy.codehaus.org/
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS ``AS IS'' AND ANY
23  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
24  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
25  * DISCLAIMED. IN NO EVENT SHALL THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR
26  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
28  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
29  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
32  * DAMAGE.
33  *
34  */

35 package org.codehaus.groovy.runtime;
36
37 import groovy.lang.MetaMethod;
38
39 import java.lang.reflect.Modifier JavaDoc;
40
41 /**
42  * A MetaMethod implementation where the underlying method is really a static
43  * helper method on some class but it appears to be an instance method on a class.
44  *
45  * This implementation is used to add new methods to the JDK writing them as normal
46  * static methods with the first parameter being the class on which the method is added.
47  *
48  * @author <a HREF="mailto:james@coredevelopers.net">James Strachan</a>
49  * @version $Revision: 1.1 $
50  */

51 public class NewInstanceMetaMethod extends MetaMethod {
52
53     private static final Class JavaDoc[] EMPTY_TYPE_ARRAY = {};
54     
55     private MetaMethod metaMethod;
56     private Class JavaDoc[] logicalParameterTypes;
57
58     public NewInstanceMetaMethod(MetaMethod metaMethod) {
59         super(metaMethod);
60         this.metaMethod = metaMethod;
61         Class JavaDoc[] realParameterTypes = metaMethod.getParameterTypes();
62         int size = realParameterTypes.length;
63         if (size <= 1) {
64             logicalParameterTypes = EMPTY_TYPE_ARRAY;
65         }
66         else {
67             logicalParameterTypes = new Class JavaDoc[--size];
68             System.arraycopy(realParameterTypes, 1, logicalParameterTypes, 0, size);
69         }
70     }
71
72     public Class JavaDoc getDeclaringClass() {
73         return getBytecodeParameterTypes()[0];
74     }
75
76     public boolean isStatic() {
77         return false;
78     }
79
80     public int getModifiers() {
81         // lets clear the static bit
82
return super.getModifiers() ^ Modifier.STATIC;
83     }
84
85     public Class JavaDoc[] getParameterTypes() {
86         return logicalParameterTypes;
87     }
88
89     public Class JavaDoc[] getBytecodeParameterTypes() {
90         return super.getParameterTypes();
91     }
92
93     public Object JavaDoc invoke(Object JavaDoc object, Object JavaDoc[] arguments) throws Exception JavaDoc {
94         // we need to cheat using the type
95
int size = arguments.length;
96         Object JavaDoc[] newArguments = new Object JavaDoc[size + 1];
97         newArguments[0] = object;
98         System.arraycopy(arguments, 0, newArguments, 1, size);
99         return metaMethod.invoke(null, newArguments);
100     }
101 }
102
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