/*
* 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.commons.jxpath.ri.axes;
import java.util.Stack;
import org.apache.commons.jxpath.Pointer;
import org.apache.commons.jxpath.ri.Compiler;
import org.apache.commons.jxpath.ri.EvalContext;
import org.apache.commons.jxpath.ri.compiler.NodeTest;
import org.apache.commons.jxpath.ri.compiler.NodeTypeTest;
import org.apache.commons.jxpath.ri.model.NodeIterator;
import org.apache.commons.jxpath.ri.model.NodePointer;
/**
* An EvalContext that walks the "descendant::" and "descendant-or-self::"
* axes.
*
* @author Dmitri Plotnikov
* @version $Revision: 670727 $ $Date: 2008-06-23 15:10:38 -0500 (Mon, 23 Jun 2008) $
*/
public class DescendantContext extends EvalContext {
private NodeTest nodeTest;
private boolean setStarted = false;
private Stack stack = null;
private NodePointer currentNodePointer = null;
private boolean includeSelf;
private static final NodeTest ELEMENT_NODE_TEST =
new NodeTypeTest(Compiler.NODE_TYPE_NODE);
/**
* Create a new DescendantContext.
* @param parentContext parent context
* @param includeSelf whether to include this node
* @param nodeTest test
*/
public DescendantContext(EvalContext parentContext, boolean includeSelf,
NodeTest nodeTest) {
super(parentContext);
this.includeSelf = includeSelf;
this.nodeTest = nodeTest;
}
public boolean isChildOrderingRequired() {
return true;
}
public NodePointer getCurrentNodePointer() {
if (position == 0 && !setPosition(1)) {
return null;
}
return currentNodePointer;
}
public void reset() {
super.reset();
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;
if (stack == null) {
stack = new Stack();
}
else {
stack.clear();
}
currentNodePointer = parentContext.getCurrentNodePointer();
if (currentNodePointer != null) {
if (!currentNodePointer.isLeaf()) {
stack.push(
currentNodePointer.childIterator(
ELEMENT_NODE_TEST,
false,
null));
}
if (includeSelf && currentNodePointer.testNode(nodeTest)) {
position++;
return true;
}
}
}
while (!stack.isEmpty()) {
NodeIterator it = (NodeIterator) stack.peek();
if (it.setPosition(it.getPosition() + 1)) {
currentNodePointer = it.getNodePointer();
if (!isRecursive()) {
if (!currentNodePointer.isLeaf()) {
stack.push(
currentNodePointer.childIterator(
ELEMENT_NODE_TEST,
false,
null));
}
if (currentNodePointer.testNode(nodeTest)) {
position++;
return true;
}
}
}
else {
// We get here only if the name test failed
// and the iterator ended
stack.pop();
}
}
return false;
}
/**
* Checks if we are reentering a bean we have already seen and if so
* returns true to prevent infinite recursion.
* @return boolean
*/
private boolean isRecursive() {
Object node = currentNodePointer.getNode();
for (int i = stack.size() - 1; --i >= 0;) {
NodeIterator it = (NodeIterator) stack.get(i);
Pointer pointer = it.getNodePointer();
if (pointer != null && pointer.getNode() == node) {
return true;
}
}
return false;
}
}
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