dotclassclassvisitor.java

ProGuard 是一个免费的 Java类文件的压缩

/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification
 *             of Java bytecode.
 *
 * Copyright (c) 2002-2007 Eric Lafortune ([e-mail])
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.classfile.visitor;

import proguard.classfile.*;
import proguard.classfile.attribute.CodeAttribute;
import proguard.classfile.constant.*;
import proguard.classfile.instruction.*;
import proguard.classfile.instruction.visitor.InstructionVisitor;
import proguard.classfile.util.*;
import proguard.classfile.constant.visitor.ConstantVisitor;
import proguard.util.ClassNameListMatcher;


/**
 * This InstructionVisitor lets a given <code>ClassVisitor</code> visit all
 * classes involved in any <code>.class</code> constructs that it visits.
 * <p>
 * Note that before JDK 1.5, <code>.class</code> constructs are actually
 * compiled differently, using <code>Class.forName</code> constructs.
 *
 * @see ClassForNameClassVisitor
 *
 * @author Eric Lafortune
 */
public class DotClassClassVisitor
extends      SimplifiedVisitor
implements   InstructionVisitor,
             ConstantVisitor
{
    private ClassVisitor classVisitor;


    /**
     * Creates a new ClassHierarchyTraveler.
     * @param classVisitor the <code>ClassVisitor</code> to which visits will
     *                     be delegated.
     */
    public DotClassClassVisitor(ClassVisitor classVisitor)
    {
        this.classVisitor = classVisitor;
    }


    // Implementations for InstructionVisitor.

    public void visitAnyInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, Instruction instruction) {}


    public void visitConstantInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, ConstantInstruction constantInstruction)
    {
        byte opcode = constantInstruction.opcode;

        // Could this instruction be a .class construct?
        if (opcode == InstructionConstants.OP_LDC ||
            opcode == InstructionConstants.OP_LDC_W)
        {
            clazz.constantPoolEntryAccept(constantInstruction.constantIndex,
                                          this);
        }
    }


    // Implementations for ConstantVisitor.

    public void visitAnyConstant(Clazz clazz, Constant constant) {}


    public void visitClassConstant(Clazz clazz, ClassConstant classConstant)
    {
        // Visit the referenced class from the .class construct.
        classConstant.referencedClassAccept(classVisitor);
    }
}