BeanClassAdapter


1   /**
2    * EasyBeans
3    * Copyright (C) 2006 Bull S.A.S.
4    * Contact: easybeans@objectweb.org
5    *
6    * This library is free software; you can redistribute it and/or
7    * modify it under the terms of the GNU Lesser General Public
8    * License as published by the Free Software Foundation; either
9    * version 2.1 of the License, or any later version.
10   *
11   * This library is distributed in the hope that it will be useful,
12   * but WITHOUT ANY WARRANTY; without even the implied warranty of
13   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14   * Lesser General Public License for more details.
15   *
16   * You should have received a copy of the GNU Lesser General Public
17   * License along with this library; if not, write to the Free Software
18   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
19   * USA
20   *
21   * --------------------------------------------------------------------------
22   * $Id: BeanClassAdapter.java 1133 2006-10-04 14:30:41Z benoitf $
23   * --------------------------------------------------------------------------
24   */
25  
26  package org.objectweb.easybeans.enhancer.bean;
27  
28  import org.objectweb.asm.ClassAdapter;
29  import org.objectweb.asm.ClassVisitor;
30  import org.objectweb.asm.MethodAdapter;
31  import org.objectweb.asm.MethodVisitor;
32  import org.objectweb.asm.Opcodes;
33  import org.objectweb.asm.Type;
34  import org.objectweb.easybeans.api.Factory;
35  import org.objectweb.easybeans.api.bean.EasyBeansBean;
36  import org.objectweb.easybeans.api.bean.EasyBeansMDB;
37  import org.objectweb.easybeans.api.bean.EasyBeansSFSB;
38  import org.objectweb.easybeans.api.bean.EasyBeansSLSB;
39  import org.objectweb.easybeans.api.container.EZBEJBContext;
40  import org.objectweb.easybeans.deployment.annotations.metadata.ClassAnnotationMetadata;
41  import org.objectweb.easybeans.enhancer.CommonClassGenerator;
42  import org.objectweb.easybeans.enhancer.interceptors.EasyBeansInvocationContextGenerator;
43  
44  /**
45   * This class adds a bean interface to the parsed object.<br>
46   * It also adds getEasyBeansFactory method defined in the EasyBeansBean interface.<br>
47   * Stateless bean will have EasyBeansStatelessSessionBean interface, etc.
48   * @author Florent Benoit
49   */
50  public class BeanClassAdapter extends ClassAdapter implements Opcodes {
51  
52      /**
53       * Metadata available by this adapter for a class.
54       */
55      private ClassAnnotationMetadata classAnnotationMetadata = null;
56  
57      /**
58       * Constructor.
59       * @param classAnnotationMetadata object containing all attributes of the
60       *        class
61       * @param cv the class visitor to which this adapter must delegate calls.
62       */
63      public BeanClassAdapter(final ClassAnnotationMetadata classAnnotationMetadata, final ClassVisitor cv) {
64          super(cv);
65          this.classAnnotationMetadata = classAnnotationMetadata;
66      }
67  
68      /**
69       * Visits the header of the class.
70       * @param version the class version.
71       * @param access the class's access flags (see
72       *        {@link org.objectweb.asm.Opcodes}). This parameter also indicates
73       *        if the class is deprecated.
74       * @param name the internal name of the class (see
75       *        {@link org.objectweb.asm.Type#getInternalName() getInternalName}).
76       * @param signature the signature of this class. May be <tt>null</tt> if
77       *        the class is not a generic one, and does not extend or implement
78       *        generic classes or interfaces.
79       * @param superName the internal of name of the super class (see
80       *        {@link org.objectweb.asm.Type#getInternalName() getInternalName}).
81       *        For interfaces, the super class is {@link Object}. May be
82       *        <tt>null</tt>, but only for the {@link Object} class.
83       * @param interfaces the internal names of the class's interfaces (see
84       *        {@link org.objectweb.asm.Type#getInternalName() getInternalName}).
85       *        May be <tt>null</tt>.
86       */
87      @Override  
88      public void visit(final int version, final int access, final String   name, final String   signature,
89              final String   superName, final String  [] interfaces) {
90  
91          String  [] newInterfaces = null;
92  
93          // Add new interface with bean
94          if (classAnnotationMetadata.isBean()) {
95              // copy old interfaces in the new array
96              newInterfaces = new String  [interfaces.length + 1];
97              System.arraycopy(interfaces, 0, newInterfaces, 0, interfaces.length);
98  
99              int indexElement = newInterfaces.length - 1;
100 
101             // Add the right interface (SLSB, SFSB, MDB)
102             if (classAnnotationMetadata.isStateless()) {
103                 newInterfaces[indexElement] = Type.getInternalName(EasyBeansSLSB.class);
104             } else if (classAnnotationMetadata.isStateful()) {
105                 newInterfaces[indexElement] = Type.getInternalName(EasyBeansSFSB.class);
106             } else if (classAnnotationMetadata.isMdb()) {
107                 newInterfaces[indexElement] = Type.getInternalName(EasyBeansMDB.class);
108             } else {
109                 newInterfaces[indexElement] = Type.getInternalName(EasyBeansBean.class);
110             }
111         } else {
112             newInterfaces = interfaces;
113         }
114 
115         super.visit(version, access, name, signature, superName, newInterfaces);
116 
117     }
118     /**
119      * Visits a method of the class. This method <i>must</i> return a new
120      * {@link MethodVisitor} instance (or <tt>null</tt>) each time it is
121      * called, i.e., it should not return a previously returned visitor.
122      *
123      * @param access the method's access flags (see {@link Opcodes}). This
124      *        parameter also indicates if the method is synthetic and/or
125      *        deprecated.
126      * @param name the method's name.
127      * @param desc the method's descriptor (see {@link Type Type}).
128      * @param signature the method's signature. May be <tt>null</tt> if the
129      *        method parameters, return type and exceptions do not use generic
130      *        types.
131      * @param exceptions the internal names of the method's exception classes
132      *        (see {@link Type#getInternalName() getInternalName}). May be
133      *        <tt>null</tt>.
134      * @return an object to visit the byte code of the method, or <tt>null</tt>
135      *         if this class visitor is not interested in visiting the code of
136      *         this method.
137      */
138     @Override  
139     public MethodVisitor visitMethod(final int access, final String   name, final String   desc, final String   signature,
140             final String  [] exceptions) {
141 
142         // if default constructor, then needs to add a call to create a new InterceptorManager
143         if ("<init>".equals(name) && "()V".equals(desc)) {
144             MethodVisitor mv =  super.visitMethod(access, name, desc, signature, exceptions);
145             return new AddMethodConstructorAdapter(mv);
146         }
147         return super.visitMethod(access, name, desc, signature, exceptions);
148 
149     }
150 
151 
152     /**
153      * Visits the end of the class. This method, which is the last one to be
154      * called, is used to inform the visitor that all the fields and methods of
155      * the class have been visited.
156      */
157     @Override  
158     public void visitEnd() {
159         super.visitEnd();
160 
161         // Adds the factory attribute and its getter/setter.
162         CommonClassGenerator.addFieldGettersSetters(cv, classAnnotationMetadata.getClassName(),
163                 "easyBeansFactory", Factory.class);
164 
165 
166         if (classAnnotationMetadata.isBean()) {
167             // Adds interceptor manager
168             CommonClassGenerator.addFieldGettersSetters(cv, classAnnotationMetadata.getClassName(),
169                     "easyBeansInterceptorManager", "L" + classAnnotationMetadata.getClassName()
170                             + EasyBeansInvocationContextGenerator.SUFFIX_INTERCEPTOR_MANAGER + ";");
171 
172 
173             // Adds the context attribute and its getter/setter.
174             CommonClassGenerator.addFieldGettersSetters(cv, classAnnotationMetadata.getClassName(),
175                     "easyBeansContext", EZBEJBContext.class);
176 
177             // Add the removed attribute (if bean has been removed)
178             if (classAnnotationMetadata.isSession()) {
179                 CommonClassGenerator.addFieldGettersSetters(cv, classAnnotationMetadata.getClassName(),
180                         "easyBeansRemoved", Boolean.TYPE);
181             }
182 
183             // Add id field for stateful
184             if (classAnnotationMetadata.isStateful()) {
185                 CommonClassGenerator.addFieldGettersSetters(cv, classAnnotationMetadata.getClassName(),
186                         "easyBeansStatefulID", Long  .class);
187             }
188 
189         }
190 
191     }
192 
193     /**
194      * Adds an entry in the constructor of the bean.
195      * It will initialize the interceptorManager.
196      * @author Florent Benoit
197      */
198     public class AddMethodConstructorAdapter extends MethodAdapter {
199 
200         /**
201          * Constructs a new AddMethodConstructorAdapter object.
202          * @param mv the code visitor to which this adapter must delegate calls.
203          */
204         public AddMethodConstructorAdapter(final MethodVisitor mv) {
205             super(mv);
206         }
207 
208         /**
209          * Adds instruction just after the start of the method code.
210          * TODO: Analyze when call to super() constructor is done and add instruction after.
211          */
212         @Override  
213         public void visitCode() {
214             super.visitCode();
215             String   clManager = classAnnotationMetadata.getClassName()
216             + EasyBeansInvocationContextGenerator.SUFFIX_INTERCEPTOR_MANAGER;
217             mv.visitVarInsn(ALOAD, 0);
218             mv.visitTypeInsn(NEW, clManager);
219             mv.visitInsn(DUP);
220             mv.visitMethodInsn(INVOKESPECIAL, clManager, "<init>", "()V");
221             mv.visitFieldInsn(PUTFIELD, classAnnotationMetadata.getClassName(), "easyBeansInterceptorManager", "L"
222                     + clManager + ";");
223 
224         }
225 
226     }
227 
228 }
229 
230
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