/*
* 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.
*/
/*
* $Id: FlowList.java 468650 2006-10-28 07:03:30Z minchau $
*/
package org.apache.xalan.xsltc.compiler;
import java.util.Iterator;
import java.util.Vector;
import org.apache.bcel.generic.BranchHandle;
import org.apache.bcel.generic.InstructionHandle;
import org.apache.bcel.generic.InstructionList;
/**
* @author Jacek Ambroziak
* @author Santiago Pericas-Geertsen
*/
public final class FlowList {
private Vector _elements;
public FlowList() {
_elements = null;
}
public FlowList(InstructionHandle bh) {
_elements = new Vector();
_elements.addElement(bh);
}
public FlowList(FlowList list) {
_elements = list._elements;
}
public FlowList add(InstructionHandle bh) {
if (_elements == null) {
_elements = new Vector();
}
_elements.addElement(bh);
return this;
}
public FlowList append(FlowList right) {
if (_elements == null) {
_elements = right._elements;
}
else {
final Vector temp = right._elements;
if (temp != null) {
final int n = temp.size();
for (int i = 0; i < n; i++) {
_elements.addElement(temp.elementAt(i));
}
}
}
return this;
}
/**
* Back patch a flow list. All instruction handles must be branch handles.
*/
public void backPatch(InstructionHandle target) {
if (_elements != null) {
final int n = _elements.size();
for (int i = 0; i < n; i++) {
BranchHandle bh = (BranchHandle)_elements.elementAt(i);
bh.setTarget(target);
}
_elements.clear(); // avoid backpatching more than once
}
}
/**
* Redirect the handles from oldList to newList. "This" flow list
* is assumed to be relative to oldList.
*/
public FlowList copyAndRedirect(InstructionList oldList,
InstructionList newList)
{
final FlowList result = new FlowList();
if (_elements == null) {
return result;
}
final int n = _elements.size();
final Iterator oldIter = oldList.iterator();
final Iterator newIter = newList.iterator();
while (oldIter.hasNext()) {
final InstructionHandle oldIh = (InstructionHandle) oldIter.next();
final InstructionHandle newIh = (InstructionHandle) newIter.next();
for (int i = 0; i < n; i++) {
if (_elements.elementAt(i) == oldIh) {
result.add(newIh);
}
}
}
return result;
}
}