programmember.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 library 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 library 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 Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.classfile;


import proguard.classfile.visitor.*;
import proguard.classfile.attribute.*;
import proguard.classfile.attribute.visitor.AttributeVisitor;

import java.io.*;

/**
 * Representation of a field or method from a program class.
 *
 * @author Eric Lafortune
 */
public abstract class ProgramMember implements Member
{
    public int         u2accessFlags;
    public int         u2nameIndex;
    public int         u2descriptorIndex;
    public int         u2attributesCount;
    public Attribute[] attributes;

    /**
     * An extra field in which visitors can store information.
     */
    public Object visitorInfo;


    protected ProgramMember() {}


    /**
     * Returns the line number range of the given class member as "m:n",
     * if it can find it, or <code>null</code> otherwise.
     */
    public String getLineNumberRange(Clazz clazz)
    {
        CodeAttribute codeAttribute =
            (CodeAttribute)getAttribute(clazz, ClassConstants.ATTR_Code);
        if (codeAttribute  == null)
        {
            return null;
        }

        LineNumberTableAttribute lineNumberTableAttribute =
            (LineNumberTableAttribute)codeAttribute.getAttribute(clazz,
                                                                 ClassConstants.ATTR_LineNumberTable);
        if (lineNumberTableAttribute  == null)
        {
            return null;
        }

        return "" +
               lineNumberTableAttribute.getLineNumber(0) +
               ":" +
               lineNumberTableAttribute.getLineNumber(Integer.MAX_VALUE);
    }


    /**
     * Returns the (first) attribute with the given name.
     */
    private Attribute getAttribute(Clazz clazz, String name)
    {
        for (int index = 0; index < u2attributesCount; index++)
        {
            Attribute attribute = attributes[index];
            if (attribute.getAttributeName(clazz).equals(name))
            {
                return attribute;
            }
        }

        return null;
    }


    /**
     * Accepts the given member info visitor.
     */
    public abstract void accept(ProgramClass  programClass,
                                MemberVisitor memberVisitor);



    /**
     * Lets the given attribute info visitor visit all the attributes of
     * this member info.
     */
    public abstract void attributesAccept(ProgramClass     programClass,
                                          AttributeVisitor attributeVisitor);


    // Implementations for Member.

    public int getAccessFlags()
    {
        return u2accessFlags;
    }

    public String getName(Clazz clazz)
    {
        return clazz.getString(u2nameIndex);
    }

    public String getDescriptor(Clazz clazz)
    {
        return clazz.getString(u2descriptorIndex);
    }

    public void accept(Clazz clazz, MemberVisitor memberVisitor)
    {
        accept((ProgramClass)clazz, memberVisitor);
    }


    // Implementations for VisitorAccepter.

    public Object getVisitorInfo()
    {
        return visitorInfo;
    }

    public void setVisitorInfo(Object visitorInfo)
    {
        this.visitorInfo = visitorInfo;
    }
}