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Java > Open Source Codes > proguard > classfile > visitor > ExceptionOffsetFilter


1 /*
2  * ProGuard -- shrinking, optimization, obfuscation, and preverification
3  * of Java bytecode.
4  *
5  * Copyright (c) 2002-2007 Eric Lafortune (eric@graphics.cornell.edu)
6  *
7  * This library is free software; you can redistribute it and/or modify it
8  * under the terms of the GNU General Public License as published by the Free
9  * Software Foundation; either version 2 of the License, or (at your option)
10  * any later version.
11  *
12  * This library is distributed in the hope that it will be useful, but WITHOUT
13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
15  * for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public License
18  * along with this library; if not, write to the Free Software Foundation,
19  * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20  */

21 package proguard.classfile.visitor;
22
23 import proguard.classfile.attribute.visitor.ExceptionInfoVisitor;
24 import proguard.classfile.attribute.*;
25 import proguard.classfile.*;
26
27 /**
28  * This <code>ExceptionInfoVisitor</code> delegates its visits to another given
29  * <code>ExceptionInfoVisitor</code>, but only when the visited exception
30  * covers the instruction at the given offset.
31  *
32  * @author Eric Lafortune
33  */

34 public class ExceptionOffsetFilter
35 implements ExceptionInfoVisitor
36 {
37     private int instructionOffset;
38     private ExceptionInfoVisitor exceptionInfoVisitor;
39
40
41     /**
42      * Creates a new ExceptionOffsetFilter.
43      * @param instructionOffset the instruction offset.
44      * @param exceptionInfoVisitor the ExceptionInfoVisitor to which visits
45      * will be delegated.
46      */

47     public ExceptionOffsetFilter(int instructionOffset,
48                                  ExceptionInfoVisitor exceptionInfoVisitor)
49     {
50         this.instructionOffset = instructionOffset;
51         this.exceptionInfoVisitor = exceptionInfoVisitor;
52     }
53
54
55     // Implementations for ExceptionInfoVisitor.
56

57     public void visitExceptionInfo(Clazz clazz, Method method, CodeAttribute codeAttribute, ExceptionInfo exceptionInfo)
58     {
59         if (exceptionInfo.isApplicable(instructionOffset))
60         {
61             exceptionInfoVisitor.visitExceptionInfo(clazz, method, codeAttribute, exceptionInfo);
62         }
63     }
64 }
65
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