SubclassFilter.java revision db267bc191f906f55eaef21a27110cce2ec57fdf 
1/*
2 * ProGuard -- shrinking, optimization, obfuscation, and preverification
3 *             of Java bytecode.
4 *
5 * Copyright (c) 2002-2009 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 */
21package proguard.classfile.visitor;
22
23import proguard.classfile.*;
24
25/**
26 * This <code>ClassVisitor</code> delegates its visits to another given
27 * <code>ClassVisitor</code>, except for classes that have a given class as
28 * direct subclass.
29 *
30 * @author Eric Lafortune
31 */
32public class SubclassFilter implements ClassVisitor
33{
34    private final Clazz        subclass;
35    private final ClassVisitor classVisitor;
36
37
38    /**
39     * Creates a new SubclassFilter.
40     * @param subclass     the class whose superclasses will not be visited.
41     * @param classVisitor the <code>ClassVisitor</code> to which visits will
42     *                     be delegated.
43     */
44    public SubclassFilter(Clazz        subclass,
45                          ClassVisitor classVisitor)
46    {
47        this.subclass     = subclass;
48        this.classVisitor = classVisitor;
49    }
50
51
52    // Implementations for ClassVisitor.
53
54    public void visitProgramClass(ProgramClass programClass)
55    {
56        if (!present(programClass.subClasses))
57        {
58            classVisitor.visitProgramClass(programClass);
59        }
60    }
61
62
63    public void visitLibraryClass(LibraryClass libraryClass)
64    {
65        if (!present(libraryClass.subClasses))
66        {
67            classVisitor.visitLibraryClass(libraryClass);
68        }
69    }
70
71
72    // Small utility methods.
73
74    private boolean present(Clazz[] subclasses)
75    {
76        if (subclasses == null)
77        {
78            return false;
79        }
80
81        for (int index = 0; index < subclasses.length; index++)
82        {
83            if (subclasses[index].equals(subclass))
84            {
85                return true;
86            }
87        }
88
89        return false;
90    }
91}