NullType.java revision 8a6199f0c36a778f22394364347a301b0b28e94b 
1/*
2 * ProGuard -- shrinking, optimization, obfuscation, and preverification
3 *             of Java bytecode.
4 *
5 * Copyright (c) 2002-2013 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.attribute.preverification;
22
23import proguard.classfile.*;
24import proguard.classfile.attribute.CodeAttribute;
25import proguard.classfile.attribute.preverification.visitor.VerificationTypeVisitor;
26
27/**
28 * This VerificationType represents a Null type.
29 *
30 * @author Eric Lafortune
31 */
32public class NullType extends VerificationType
33{
34    // Implementations for VerificationType.
35
36    public int getTag()
37    {
38        return NULL_TYPE;
39    }
40
41
42    public void accept(Clazz clazz, Method method, CodeAttribute codeAttribute, int instructionOffset, VerificationTypeVisitor verificationTypeVisitor)
43    {
44        verificationTypeVisitor.visitNullType(clazz, method, codeAttribute, instructionOffset, this);
45    }
46
47
48    public void stackAccept(Clazz clazz, Method method, CodeAttribute codeAttribute, int instructionOffset, int stackIndex, VerificationTypeVisitor verificationTypeVisitor)
49    {
50        verificationTypeVisitor.visitStackNullType(clazz, method, codeAttribute, instructionOffset, stackIndex, this);
51    }
52
53
54    public void variablesAccept(Clazz clazz, Method method, CodeAttribute codeAttribute, int instructionOffset, int variableIndex, VerificationTypeVisitor verificationTypeVisitor)
55    {
56        verificationTypeVisitor.visitVariablesNullType(clazz, method, codeAttribute, instructionOffset, variableIndex, this);
57    }
58
59
60    // Implementations for Object.
61
62    public String toString()
63    {
64        return "n";
65    }
66}
67