DotClassClassVisitor.java revision b72c5c2e5482cf10117b2b25f642f7616b2326c3 
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.*;
24import proguard.classfile.attribute.CodeAttribute;
25import proguard.classfile.constant.*;
26import proguard.classfile.constant.visitor.ConstantVisitor;
27import proguard.classfile.instruction.*;
28import proguard.classfile.instruction.visitor.InstructionVisitor;
29import proguard.classfile.util.SimplifiedVisitor;
30
31
32/**
33 * This InstructionVisitor lets a given <code>ClassVisitor</code> visit all
34 * classes involved in any <code>.class</code> constructs that it visits.
35 * <p>
36 * Note that before JDK 1.5, <code>.class</code> constructs are actually
37 * compiled differently, using <code>Class.forName</code> constructs.
38 *
39 * @see ClassForNameClassVisitor
40 *
41 * @author Eric Lafortune
42 */
43public class DotClassClassVisitor
44extends      SimplifiedVisitor
45implements   InstructionVisitor,
46             ConstantVisitor
47{
48    private final ClassVisitor classVisitor;
49
50
51    /**
52     * Creates a new ClassHierarchyTraveler.
53     * @param classVisitor the <code>ClassVisitor</code> to which visits will
54     *                     be delegated.
55     */
56    public DotClassClassVisitor(ClassVisitor classVisitor)
57    {
58        this.classVisitor = classVisitor;
59    }
60
61
62    // Implementations for InstructionVisitor.
63
64    public void visitAnyInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, Instruction instruction) {}
65
66
67    public void visitConstantInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, ConstantInstruction constantInstruction)
68    {
69        byte opcode = constantInstruction.opcode;
70
71        // Could this instruction be a .class construct?
72        if (opcode == InstructionConstants.OP_LDC ||
73            opcode == InstructionConstants.OP_LDC_W)
74        {
75            clazz.constantPoolEntryAccept(constantInstruction.constantIndex,
76                                          this);
77        }
78    }
79
80
81    // Implementations for ConstantVisitor.
82
83    public void visitAnyConstant(Clazz clazz, Constant constant) {}
84
85
86    public void visitClassConstant(Clazz clazz, ClassConstant classConstant)
87    {
88        // Visit the referenced class from the .class construct.
89        classConstant.referencedClassAccept(classVisitor);
90    }
91}
92