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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package org.apache.bcel.generic;
import org.apache.bcel.Const;
import org.apache.bcel.classfile.LocalVariable;
/**
* This class represents a local variable within a method. It contains its
* scope, name and type. The generated LocalVariable object can be obtained
* with getLocalVariable which needs the instruction list and the constant
* pool as parameters.
*
* @version $Id$
* @see LocalVariable
* @see MethodGen
*/
public class LocalVariableGen implements InstructionTargeter, NamedAndTyped, Cloneable {
private int index;
private String name;
private Type type;
private InstructionHandle start;
private InstructionHandle end;
/**
* Generate a local variable that with index `index'. Note that double and long
* variables need two indexs. Index indices have to be provided by the user.
*
* @param index index of local variable
* @param name its name
* @param type its type
* @param start from where the instruction is valid (null means from the start)
* @param end until where the instruction is valid (null means to the end)
*/
public LocalVariableGen(final int index, final String name, final Type type, final InstructionHandle start,
final InstructionHandle end) {
if ((index < 0) || (index > Const.MAX_SHORT)) {
throw new ClassGenException("Invalid index index: " + index);
}
this.name = name;
this.type = type;
this.index = index;
setStart(start);
setEnd(end);
}
/**
* Get LocalVariable object.
*
* This relies on that the instruction list has already been dumped to byte code or
* or that the `setPositions' methods has been called for the instruction list.
*
* Note that for local variables whose scope end at the last
* instruction of the method's code, the JVM specification is ambiguous:
* both a start_pc+length ending at the last instruction and
* start_pc+length ending at first index beyond the end of the code are
* valid.
*
* @param cp constant pool
*/
public LocalVariable getLocalVariable( final ConstantPoolGen cp ) {
int start_pc = 0;
int length = 0;
if ((start != null) && (end != null)) {
start_pc = start.getPosition();
length = end.getPosition() - start_pc;
if (end.getNext() == null) {
length += end.getInstruction().getLength();
}
}
final int name_index = cp.addUtf8(name);
final int signature_index = cp.addUtf8(type.getSignature());
return new LocalVariable(start_pc, length, name_index, signature_index, index, cp
.getConstantPool());
}
public void setIndex( final int index ) {
this.index = index;
}
public int getIndex() {
return index;
}
@Override
public void setName( final String name ) {
this.name = name;
}
@Override
public String getName() {
return name;
}
@Override
public void setType( final Type type ) {
this.type = type;
}
@Override
public Type getType() {
return type;
}
public InstructionHandle getStart() {
return start;
}
public InstructionHandle getEnd() {
return end;
}
public void setStart( final InstructionHandle start ) { // TODO could be package-protected?
BranchInstruction.notifyTarget(this.start, start, this);
this.start = start;
}
public void setEnd( final InstructionHandle end ) { // TODO could be package-protected?
BranchInstruction.notifyTarget(this.end, end, this);
this.end = end;
}
/**
* @param old_ih old target, either start or end
* @param new_ih new target
*/
@Override
public void updateTarget( final InstructionHandle old_ih, final InstructionHandle new_ih ) {
boolean targeted = false;
if (start == old_ih) {
targeted = true;
setStart(new_ih);
}
if (end == old_ih) {
targeted = true;
setEnd(new_ih);
}
if (!targeted) {
throw new ClassGenException("Not targeting " + old_ih + ", but {" + start + ", " + end
+ "}");
}
}
/**
* Clear the references from and to this variable when it's removed.
*/
void dispose() {
setStart(null);
setEnd(null);
}
/**
* @return true, if ih is target of this variable
*/
@Override
public boolean containsTarget( final InstructionHandle ih ) {
return (start == ih) || (end == ih);
}
@Override
public int hashCode() {
// If the user changes the name or type, problems with the targeter hashmap will occur.
// Note: index cannot be part of hash as it may be changed by the user.
return name.hashCode() ^ type.hashCode();
}
/**
* We consider to local variables to be equal, if the use the same index and
* are valid in the same range.
*/
@Override
public boolean equals( final Object o ) {
if (!(o instanceof LocalVariableGen)) {
return false;
}
final LocalVariableGen l = (LocalVariableGen) o;
return (l.index == index) && (l.start == start) && (l.end == end);
}
@Override
public String toString() {
return "LocalVariableGen(" + name + ", " + type + ", " + start + ", " + end + ")";
}
@Override
public Object clone() {
try {
return super.clone();
} catch (final CloneNotSupportedException e) {
throw new Error("Clone Not Supported"); // never happens
}
}
}
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