KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > org > codehaus > aspectwerkz > aspect > DefaultMixinFactory


1 /**************************************************************************************
2  * Copyright (c) Jonas BonŽr, Alexandre Vasseur. All rights reserved. *
3  * http://aspectwerkz.codehaus.org *
4  * ---------------------------------------------------------------------------------- *
5  * The software in this package is published under the terms of the LGPL license *
6  * a copy of which has been included with this distribution in the license.txt file. *
7  **************************************************************************************/
8 package org.codehaus.aspectwerkz.aspect;
9
10 import java.lang.reflect.InvocationTargetException JavaDoc;
11 import java.util.WeakHashMap JavaDoc;
12 import java.util.Map JavaDoc;
13
14 import org.codehaus.aspectwerkz.exception.DefinitionException;
15 import org.codehaus.aspectwerkz.exception.WrappedRuntimeException;
16 import org.codehaus.aspectwerkz.DeploymentModel;
17
18 /**
19  * Abstract base class for the mixin factory implementations.
20  *
21  * @author <a HREF="mailto:jboner@codehaus.org">Jonas BonŽr </a>
22  * @author <a HREF="mailto:alex AT gnilux DOT com">Alexandre Vasseur</a>
23  */
24 public class DefaultMixinFactory extends AbstractMixinFactory {
25
26     private static final Object JavaDoc[] EMPTY_OBJECT_ARRAY = new Object JavaDoc[0];
27
28     private Object JavaDoc m_perJVM = null;
29
30     private Map JavaDoc m_perClassMixins = new WeakHashMap JavaDoc();
31
32     private Map JavaDoc m_perInstanceMixins = new WeakHashMap JavaDoc();
33
34     /**
35      * Creates a new default mixin factory.
36      *
37      * @param mixinClass
38      * @param deploymentModel
39      */
40     public DefaultMixinFactory(final Class JavaDoc mixinClass, final DeploymentModel deploymentModel) {
41         super(mixinClass, deploymentModel);
42     }
43
44     /**
45      * Creates a new perJVM mixin instance.
46      *
47      * @return the mixin instance
48      */
49     public Object JavaDoc mixinOf() {
50         if (m_perJVM != null) {
51             return m_perJVM;
52         }
53         synchronized (this) {
54             final Object JavaDoc mixin;
55             if (m_deploymentModel == DeploymentModel.PER_JVM) {
56                 try {
57                     mixin = m_defaultConstructor.newInstance(EMPTY_OBJECT_ARRAY);
58                 } catch (InvocationTargetException JavaDoc e) {
59                     throw new WrappedRuntimeException(e.getTargetException());
60                 } catch (Exception JavaDoc e) {
61                     throw new WrappedRuntimeException(e);
62                 }
63             } else {
64                 throw new DefinitionException(
65                         "Mixins.mixinOf() is can not be invoked for mixin deployed using as " +
66                         m_deploymentModel
67                 );
68             }
69             m_perJVM = mixin;
70         }
71         return m_perJVM;
72     }
73
74     /**
75      * Creates a new perClass mixin instance.
76      *
77      * @param klass
78      * @return the mixin instance
79      */
80     public Object JavaDoc mixinOf(final Class JavaDoc klass) {
81         if (m_perClassMixins.containsKey(klass)) {
82             return m_perClassMixins.get(klass);
83         }
84         synchronized (m_perClassMixins) {
85             if (!m_perClassMixins.containsKey(klass)) {
86                 final Object JavaDoc mixin;
87                 if (m_deploymentModel == DeploymentModel.PER_CLASS) {
88                     try {
89                         if (m_perClassConstructor != null) {
90                             mixin = m_perClassConstructor.newInstance(new Object JavaDoc[]{klass});
91                         } else if (m_defaultConstructor != null) {
92                             mixin = m_defaultConstructor.newInstance(new Object JavaDoc[]{});
93                         } else {
94                             throw new DefinitionException(
95                                     "no valid constructor found for mixin [" + m_mixinClass.getName() + "]"
96                             );
97                         }
98                     } catch (InvocationTargetException JavaDoc e) {
99                         throw new WrappedRuntimeException(e.getTargetException());
100                     } catch (Exception JavaDoc e) {
101                         throw new WrappedRuntimeException(e);
102                     }
103                 } else {
104                     throw new DefinitionException(
105                             "Mixins.mixinOf(Class) is can not be invoked for mixin deployed using as " +
106                             m_deploymentModel
107                     );
108                 }
109                 m_perClassMixins.put(klass, mixin);
110             }
111             return m_perClassMixins.get(klass);
112         }
113     }
114
115     /**
116      * Creates a new perInstance mixin instance.
117      *
118      * @param instance
119      * @return the mixin instance
120      */
121     public Object JavaDoc mixinOf(final Object JavaDoc instance) {
122         if (m_perInstanceMixins.containsKey(instance)) {
123             return m_perInstanceMixins.get(instance);
124         }
125         synchronized (m_perInstanceMixins) {
126             if (!m_perInstanceMixins.containsKey(instance)) {
127                 final Object JavaDoc mixin;
128                 if (m_deploymentModel == DeploymentModel.PER_INSTANCE) {
129                     try {
130                         if (m_perInstanceConstructor != null) {
131                             mixin = m_perInstanceConstructor.newInstance(new Object JavaDoc[]{instance});
132                         } else if (m_defaultConstructor != null) {
133                             mixin = m_defaultConstructor.newInstance(new Object JavaDoc[]{});
134                         } else {
135                             throw new DefinitionException(
136                                     "no valid constructor found for mixin [" + m_mixinClass.getName() + "]"
137                             );
138                         }
139                     } catch (InvocationTargetException JavaDoc e) {
140                         throw new WrappedRuntimeException(e.getTargetException());
141                     } catch (Exception JavaDoc e) {
142                         throw new WrappedRuntimeException(e);
143                     }
144                 } else {
145                     throw new DefinitionException(
146                             "Mixins.mixinOf(Object) is can not be invoked for mixin deployed using as " +
147                             m_deploymentModel
148                     );
149                 }
150                 m_perInstanceMixins.put(instance, mixin);
151             }
152             return m_perInstanceMixins.get(instance);
153         }
154     }
155 }
Popular Tags