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


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.util.HashMap JavaDoc;
11 import java.util.Map JavaDoc;
12 import java.util.WeakHashMap JavaDoc;
13
14 import org.codehaus.aspectwerkz.AspectContext;
15
16
17 /**
18  * Abstract base class for the aspect container implementations.
19  *
20  * @author <a HREF="mailto:jboner@codehaus.org">Jonas BonŽr </a>
21  * @author <a HREF="mailto:alex AT gnilux DOT com">Alexandre Vasseur</a>
22  * @TODO: allow any type of constructor, to support ctor based dependency injection
23  */
24 public abstract class AbstractAspectContainer implements AspectContainer {
25
26     public static final int ASPECT_CONSTRUCTION_TYPE_UNKNOWN = 0;
27     public static final int ASPECT_CONSTRUCTION_TYPE_DEFAULT = 1;
28     public static final int ASPECT_CONSTRUCTION_TYPE_ASPECT_CONTEXT = 2;
29     public static final Object JavaDoc[] EMPTY_OBJECT_ARRAY = new Object JavaDoc[]{};
30
31     /**
32      * An array with the single aspect context, needed to save one array creation per invocation.
33      */
34     protected final Object JavaDoc[] ARRAY_WITH_SINGLE_ASPECT_CONTEXT = new Object JavaDoc[1];
35
36     /**
37      * The aspect construction type.
38      */
39     protected int m_constructionType = ASPECT_CONSTRUCTION_TYPE_UNKNOWN;
40
41     /**
42      * The aspect context prototype.
43      */
44     protected final AspectContext m_aspectContext;
45
46     /**
47      * Holds a reference to the sole per JVM aspect instance.
48      */
49     protected Object JavaDoc m_perJvm;
50
51     /**
52      * Holds references to the per class aspect instances.
53      */
54     protected final Map JavaDoc m_perClass = new WeakHashMap JavaDoc();
55
56     /**
57      * Holds references to the per instance aspect instances.
58      */
59     protected final Map JavaDoc m_perInstance = new WeakHashMap JavaDoc();
60
61     /**
62      * Holds references to the per thread aspect instances.
63      */
64     protected final Map JavaDoc m_perThread = new WeakHashMap JavaDoc();
65
66     /**
67      * Maps the advice infos to the hash codes of the the matching advice method.
68      */
69     protected final Map JavaDoc m_adviceInfos = new HashMap JavaDoc();
70
71     /**
72      * Creates a new aspect container strategy.
73      *
74      * @param aspectContext the context
75      */
76     public AbstractAspectContainer(final AspectContext aspectContext) {
77         if (aspectContext == null) {
78             throw new IllegalArgumentException JavaDoc("cross-cutting info can not be null");
79         }
80
81         m_aspectContext = aspectContext;
82         ARRAY_WITH_SINGLE_ASPECT_CONTEXT[0] = m_aspectContext;
83     }
84
85     /**
86      * Returns the context.
87      *
88      * @return the context
89      */
90     public AspectContext getContext() {
91         return m_aspectContext;
92     }
93
94     /**
95      * asm
96      * Creates a new perJVM cross-cutting instance, if it already exists then return it.
97      *
98      * @return the cross-cutting instance
99      */
100     public Object JavaDoc aspectOf() {
101         if (m_perJvm == null) {
102             m_perJvm = createAspect();
103         }
104         return m_perJvm;
105     }
106
107     /**
108      * Creates a new perClass cross-cutting instance, if it already exists then return it.
109      *
110      * @param klass
111      * @return the cross-cutting instance
112      */
113     public Object JavaDoc aspectOf(final Class JavaDoc klass) {
114         synchronized (m_perClass) {
115             if (!m_perClass.containsKey(klass)) {
116                 m_perClass.put(klass, createAspect());
117             }
118         }
119         return m_perClass.get(klass);
120     }
121
122     /**
123      * Creates a new perInstance cross-cutting instance, if it already exists then return it.
124      *
125      * @param instance
126      * @return the cross-cutting instance
127      */
128     public Object JavaDoc aspectOf(final Object JavaDoc instance) {
129         synchronized (m_perInstance) {
130             if (!m_perInstance.containsKey(instance)) {
131                 m_perInstance.put(instance, createAspect());
132             }
133         }
134         return m_perInstance.get(instance);
135     }
136
137     /**
138      * Creates a new perThread cross-cutting instance, if it already exists then return it.
139      *
140      * @param thread the thread for the aspect
141      * @return the cross-cutting instance
142      */
143     public Object JavaDoc aspectOf(final Thread JavaDoc thread) {
144         synchronized (m_perThread) {
145             if (!m_perThread.containsKey(thread)) {
146                 m_perThread.put(thread, createAspect());
147             }
148         }
149         return m_perThread.get(thread);
150     }
151
152     /**
153      * To be implemented by the concrete aspect containers. <p/>Should return a new aspect instance.
154      *
155      * @return a new aspect instance
156      */
157     protected abstract Object JavaDoc createAspect();
158 }
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