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.optimize.peephole;
22
23import proguard.classfile.*;
24import proguard.classfile.util.*;
25import proguard.classfile.visitor.*;
26import proguard.optimize.KeepMarker;
27
28/**
29 * This <code>ClassVisitor</code> makes the program classes that it visits
30 * final, if possible.
31 *
32 * @author Eric Lafortune
33 */
34public class ClassFinalizer
35extends      SimplifiedVisitor
36implements   ClassVisitor
37{
38    private final ClassVisitor extraClassVisitor;
39
40
41    /**
42     * Creates a new ClassFinalizer.
43     */
44    public ClassFinalizer()
45    {
46        this(null);
47    }
48
49
50    /**
51     * Creates a new ClassFinalizer.
52     * @param extraClassVisitor an optional extra visitor for all finalized
53     *                          classes.
54     */
55    public ClassFinalizer(ClassVisitor  extraClassVisitor)
56    {
57        this.extraClassVisitor = extraClassVisitor;
58    }
59
60
61    // Implementations for ClassVisitor.
62
63    public void visitProgramClass(ProgramClass programClass)
64    {
65        // If the class is not final/interface/abstract,
66        // and it is not being kept,
67        // and it doesn't have any subclasses,
68        // then make it final.
69        if ((programClass.u2accessFlags & (ClassConstants.INTERNAL_ACC_FINAL     |
70                                           ClassConstants.INTERNAL_ACC_INTERFACE |
71                                           ClassConstants.INTERNAL_ACC_ABSTRACT)) == 0 &&
72            !KeepMarker.isKept(programClass)                                           &&
73            programClass.subClasses == null)
74        {
75            programClass.u2accessFlags |= ClassConstants.INTERNAL_ACC_FINAL;
76
77            // Visit the class, if required.
78            if (extraClassVisitor != null)
79            {
80                extraClassVisitor.visitProgramClass(programClass);
81            }
82        }
83    }
84}
85