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


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 program 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 program 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 General Public License for
15  * more details.
16  *
17  * You should have received a copy of the GNU General Public License along
18  * with this program; if not, write to the Free Software Foundation, Inc.,
19  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20  */
21 package proguard.classfile.visitor;
22
23 import proguard.classfile.*;
24 import proguard.classfile.util.*;
25
26 /**
27  * This <code>MemberVisitor</code> delegates its visits to another given
28  * <code>MemberVisitor</code>, but only when the visited member is accessible
29  * from the given referencing class.
30  *
31  * @author Eric Lafortune
32  */
33 public class MemberClassAccessFilter
34 implements MemberVisitor
35 {
36     private Clazz referencingClass;
37     private MemberVisitor memberVisitor;
38
39
40     /**
41      * Creates a new MemberAccessFilter.
42      * @param referencingClass the class that is accessing the member.
43      * @param memberVisitor the <code>MemberVisitor</code> to which visits
44      * will be delegated.
45      */
46     public MemberClassAccessFilter(Clazz referencingClass,
47                                    MemberVisitor memberVisitor)
48     {
49         this.referencingClass = referencingClass;
50         this.memberVisitor = memberVisitor;
51     }
52
53
54     // Implementations for MemberVisitor.
55
56     public void visitProgramField(ProgramClass programClass, ProgramField programField)
57     {
58         if (accepted(programClass, programField.getAccessFlags()))
59         {
60             memberVisitor.visitProgramField(programClass, programField);
61         }
62     }
63
64
65     public void visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod)
66     {
67         if (accepted(programClass, programMethod.getAccessFlags()))
68         {
69             memberVisitor.visitProgramMethod(programClass, programMethod);
70         }
71     }
72
73
74     public void visitLibraryField(LibraryClass libraryClass, LibraryField libraryField)
75     {
76         if (accepted(libraryClass, libraryField.getAccessFlags()))
77         {
78             memberVisitor.visitLibraryField(libraryClass, libraryField);
79         }
80     }
81
82
83     public void visitLibraryMethod(LibraryClass libraryClass, LibraryMethod libraryMethod)
84     {
85         if (accepted(libraryClass, libraryMethod.getAccessFlags()))
86         {
87             memberVisitor.visitLibraryMethod(libraryClass, libraryMethod);
88         }
89     }
90
91
92     // Small utility methods.
93
94     private boolean accepted(Clazz clazz, int memberAccessFlags)
95     {
96         int accessLevel = AccessUtil.accessLevel(memberAccessFlags);
97
98         return
99             (accessLevel >= AccessUtil.PUBLIC ) ||
100             (accessLevel >= AccessUtil.PRIVATE && referencingClass.equals(clazz) ) ||
101             (accessLevel >= AccessUtil.PACKAGE_VISIBLE && (ClassUtil.internalPackageName(referencingClass.getName()).equals(
102                                                            ClassUtil.internalPackageName(clazz.getName())))) ||
103             (accessLevel >= AccessUtil.PROTECTED && (referencingClass.extends_(clazz) ||
104                                                            referencingClass.extendsOrImplements(clazz)) );
105     }
106 }
107
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