/*
* Copyright 1999-2004 The Apache Software Foundation
*
* Licensed 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.commons.jxpath.ri.axes;
import java.util.Stack;
import org.apache.commons.jxpath.ri.EvalContext;
import org.apache.commons.jxpath.ri.compiler.NodeTest;
import org.apache.commons.jxpath.ri.model.NodeIterator;
import org.apache.commons.jxpath.ri.model.NodePointer;
import org.apache.commons.jxpath.ri.model.beans.PropertyIterator;
/**
* EvalContext that walks the "preceding::" and "following::" axes.
*
* @author Dmitri Plotnikov
* @version $Revision: 1.15 $ $Date: 2004/03/25 03:49:50 $
*/
public class PrecedingOrFollowingContext extends EvalContext {
private NodeTest nodeTest;
private boolean setStarted = false;
private boolean started = false;
private Stack stack;
private Stack nameStack;
private NodePointer currentNodePointer;
private NodePointer currentRootLocation;
private boolean reverse;
public PrecedingOrFollowingContext(
EvalContext parentContext,
NodeTest nodeTest,
boolean reverse)
{
super(parentContext);
this.nodeTest = nodeTest;
this.reverse = reverse;
}
public NodePointer getCurrentNodePointer() {
return currentNodePointer;
}
public int getDocumentOrder() {
return reverse ? -1 : 1;
}
public void reset() {
super.reset();
stack = new Stack();
setStarted = false;
}
public boolean setPosition(int position) {
if (position < this.position) {
reset();
}
while (this.position < position) {
if (!nextNode()) {
return false;
}
}
return true;
}
public boolean nextNode() {
if (!setStarted) {
setStarted = true;
currentRootLocation = parentContext.getCurrentNodePointer();
NodePointer parent = currentRootLocation.getParent();
if (parent != null) {
// TBD: check type
stack.push(
parent.childIterator(null, reverse, currentRootLocation));
}
}
while (true) {
if (stack.isEmpty()) {
currentRootLocation = currentRootLocation.getParent();
if (currentRootLocation == null
|| currentRootLocation.isRoot()) {
break;
}
NodePointer parent = currentRootLocation.getParent();
if (parent != null) {
stack.push(
parent.childIterator(
null,
reverse,
currentRootLocation));
}
}
while (!stack.isEmpty()) {
if (!reverse) {
NodeIterator it = (NodeIterator) stack.peek();
if (it.setPosition(it.getPosition() + 1)) {
currentNodePointer = it.getNodePointer();
if (!currentNodePointer.isLeaf()) {
stack.push(
currentNodePointer.childIterator(
null,
reverse,
null));
}
if (currentNodePointer.testNode(nodeTest)) {
super.setPosition(getCurrentPosition() + 1);
return true;
}
}
else {
// We get here only if the name test failed
// and the iterator ended
stack.pop();
}
}
else {
NodeIterator it = (NodeIterator) stack.peek();
if (it.setPosition(it.getPosition() + 1)) {
currentNodePointer = it.getNodePointer();
if (!currentNodePointer.isLeaf()) {
stack.push(
currentNodePointer.childIterator(
null,
reverse,
null));
}
else if (currentNodePointer.testNode(nodeTest)) {
super.setPosition(getCurrentPosition() + 1);
return true;
}
}
else {
stack.pop();
if (!stack.isEmpty()) {
it = (PropertyIterator) stack.peek();
currentNodePointer = it.getNodePointer();
if (currentNodePointer.testNode(nodeTest)) {
super.setPosition(getCurrentPosition() + 1);
return true;
}
}
}
}
}
}
return false;
}
}