javassist.convert.TransformFieldAccess Maven / Gradle / Ivy
/*
* Javassist, a Java-bytecode translator toolkit.
* Copyright (C) 1999- Shigeru Chiba. All Rights Reserved.
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. Alternatively, the contents of this file may be used under
* the terms of the GNU Lesser General Public License Version 2.1 or later,
* or the Apache License Version 2.0.
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*/
package javassist.convert;
import javassist.bytecode.*;
import javassist.CtClass;
import javassist.CtField;
import javassist.Modifier;
final public class TransformFieldAccess extends Transformer {
private String newClassname, newFieldname;
private String fieldname;
private CtClass fieldClass;
private boolean isPrivate;
/* cache */
private int newIndex;
private ConstPool constPool;
public TransformFieldAccess(Transformer next, CtField field,
String newClassname, String newFieldname)
{
super(next);
this.fieldClass = field.getDeclaringClass();
this.fieldname = field.getName();
this.isPrivate = Modifier.isPrivate(field.getModifiers());
this.newClassname = newClassname;
this.newFieldname = newFieldname;
this.constPool = null;
}
public void initialize(ConstPool cp, CodeAttribute attr) {
if (constPool != cp)
newIndex = 0;
}
/**
* Modify GETFIELD, GETSTATIC, PUTFIELD, and PUTSTATIC so that
* a different field is accessed. The new field must be declared
* in a superclass of the class in which the original field is
* declared.
*/
public int transform(CtClass clazz, int pos,
CodeIterator iterator, ConstPool cp)
{
int c = iterator.byteAt(pos);
if (c == GETFIELD || c == GETSTATIC
|| c == PUTFIELD || c == PUTSTATIC) {
int index = iterator.u16bitAt(pos + 1);
String typedesc
= TransformReadField.isField(clazz.getClassPool(), cp,
fieldClass, fieldname, isPrivate, index);
if (typedesc != null) {
if (newIndex == 0) {
int nt = cp.addNameAndTypeInfo(newFieldname,
typedesc);
newIndex = cp.addFieldrefInfo(
cp.addClassInfo(newClassname), nt);
constPool = cp;
}
iterator.write16bit(newIndex, pos + 1);
}
}
return pos;
}
}