CflowBinding


1   /*
2    * All content copyright (c) 2003-2006 Terracotta, Inc., except as may otherwise be noted in a separate copyright notice.  All rights reserved.
3    */
4   package com.tc.aspectwerkz.cflow;
5   
6   
7   import com.tc.aspectwerkz.aspect.AdviceType;
8   import com.tc.aspectwerkz.definition.AdviceDefinition;
9   import com.tc.aspectwerkz.definition.AspectDefinition;
10  import com.tc.aspectwerkz.definition.SystemDefinition;
11  import com.tc.aspectwerkz.reflect.impl.java.JavaClassInfo;
12  import com.tc.aspectwerkz.reflect.MethodInfo;
13  import com.tc.aspectwerkz.reflect.ClassInfo;
14  import com.tc.aspectwerkz.expression.ExpressionInfo;
15  
16  import java.util.List  ;
17  import java.util.ArrayList  ;
18  
19  /**
20   * A Cflow binding represents an extracted cflow or cflowbelow subexpression
21   * <p/>
22   * For a given pointcut "pcA and cflowA or cflowbelowB", we will extract two bindings.
23   * The m_cflowID must be unique on a per cflow sub expresion basis ie JVM wide.
24   * <p/>
25   * Note: CflowBinding hashcode depends on Cflow_ID (sub expr) + isCflowBelow only.
26   *
27   * @author <a HREF="mailto:alex AT gnilux DOT com">Alexandre Vasseur</a>
28   */
29  public class CflowBinding {
30  
31    /**
32     * the base implementation that hosts the cflow advices
33     */
34    private final static ClassInfo ABSTRACT_CFLOWCLASS = JavaClassInfo.getClassInfo(AbstractCflowSystemAspect.class);
35    private final static MethodInfo CFLOW_ENTER_ADVICE;
36    private final static MethodInfo CFLOW_EXIT_ADVICE;
37  
38    static {
39      MethodInfo enter = null;
40      MethodInfo exit = null;
41      for (int i = 0; i < ABSTRACT_CFLOWCLASS.getMethods().length; i++) {
42        MethodInfo methodInfo = ABSTRACT_CFLOWCLASS.getMethods()[i];
43        if (methodInfo.getName().equals("enter")) {
44          enter = methodInfo;
45        } else if (methodInfo.getName().equals("exit")) {
46          exit = methodInfo;
47        }
48      }
49      if (enter == null || exit == null) {
50        throw new Error  ("Could not gather cflow advices from " + AbstractCflowSystemAspect.class);
51      } else {
52        CFLOW_ENTER_ADVICE = enter;
53        CFLOW_EXIT_ADVICE = exit;
54      }
55    }
56  
57    /**
58     * cflow unique id
59     */
60    private int m_cflowID;
61  
62    /**
63     * pointcut that represents this cflow sub-expression
64     */
65    private ExpressionInfo m_cflowSubExpression;
66  
67    /**
68     * pointcut that represents the containing expression
69     */
70    private ExpressionInfo m_outerExpression;
71  
72    /**
73     * marker if this binding is a cflow below, not used at the moment
74     */
75    private boolean m_isCflowBelow;
76  
77    /**
78     * Cosntructs a new cflow binding
79     *
80     * @param cflowID
81     * @param cflowSubExpression
82     * @param isCflowBelow
83     */
84    public CflowBinding(int cflowID, ExpressionInfo cflowSubExpression, ExpressionInfo outerExpression, boolean isCflowBelow) {
85      m_cflowID = cflowID;
86      m_cflowSubExpression = cflowSubExpression;
87      m_outerExpression = outerExpression;
88      m_isCflowBelow = isCflowBelow;
89    }
90  
91    /**
92     * @return the sub expression
93     */
94    public ExpressionInfo getExpression() {
95      return m_cflowSubExpression;
96    }
97  
98    /**
99     * Extract the cflow bindings from any pointcut
100    * This includes both cflow and cflowbelow
101    *
102    * @param expressionInfo the pointcut expression frow where to extract the cflow bindings
103    * @return a list of CflowBinding, can be empty
104    */
105   public static List   getCflowBindingsForCflowOf(ExpressionInfo expressionInfo) {
106     List   cflowBindings = new ArrayList  ();
107     if (expressionInfo != null) {
108       expressionInfo.getCflowAspectExpression().populateCflowAspectBindings(cflowBindings);
109     }
110     return cflowBindings;
111   }
112 
113   /**
114    * Create an aspect definition for this cflow binding in the given system.
115    * The cflow jit aspects will gets compiled and loaded
116    *
117    * @param systemDefinition
118    * @param loader
119    * @return the cflow aspect definition
120    */
121   public AspectDefinition getAspectDefinition(SystemDefinition systemDefinition, ClassLoader   loader) {
122     String   aspectName = CflowCompiler.getCflowAspectClassName(m_cflowID);
123 
124     // check if we have already register this aspect
125     // TODO: it may happen that the aspect gets register somewhere up in the hierarchy ??
126     // it is optim only
127 
128     // TODO: how to do this class define lazyly and not pass in a classloader ?
129     // could be done in the JIT jp clinit when 1+ advice has a cflow binding
130     Class   aspectClass = CflowCompiler.compileCflowAspectAndAttachToClassLoader(loader, m_cflowID);
131     ClassInfo cflowAspectInfo = JavaClassInfo.getClassInfo(aspectClass);
132 
133     AspectDefinition aspectDef = new AspectDefinition(
134             aspectName.replace('/', '.'),
135             cflowAspectInfo,
136             systemDefinition
137     );
138     aspectDef.addBeforeAdviceDefinition(
139             new AdviceDefinition(
140                     CFLOW_ENTER_ADVICE.getName(),
141                     AdviceType.BEFORE,
142                     null,
143                     aspectName,
144                     aspectName,
145                     m_cflowSubExpression,
146                     CFLOW_ENTER_ADVICE,
147                     aspectDef
148             )
149     );
150     aspectDef.addAfterAdviceDefinition(
151             new AdviceDefinition(
152                     CFLOW_EXIT_ADVICE.getName(),
153                     AdviceType.AFTER_FINALLY,
154                     null,
155                     aspectName,
156                     aspectName,
157                     m_cflowSubExpression,
158                     CFLOW_EXIT_ADVICE,
159                     aspectDef
160             )
161     );
162 
163     return aspectDef;
164   }
165 
166   public boolean isCflowBelow() {
167     return m_isCflowBelow;
168   }
169 
170   public int getCflowID() {
171     return m_cflowID;
172   }
173 
174   public boolean equals(Object   o) {
175     if (this == o) return true;
176     if (!(o instanceof CflowBinding)) return false;
177 
178     final CflowBinding cflowBinding = (CflowBinding) o;
179 
180     if (m_cflowID != cflowBinding.m_cflowID) return false;
181     if (m_isCflowBelow != cflowBinding.m_isCflowBelow) return false;
182 
183     return true;
184   }
185 
186   public int hashCode() {
187     int result;
188     result = m_cflowID;
189     result = 29 * result + (m_isCflowBelow ? 1 : 0);
190     return result;
191   }
192 }
193
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags