- /*
- * 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.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: 1.16 $ $Date: 2004/02/29 14:17:38 $
- */
- public class DescendantContext extends EvalContext {
- private NodeTest nodeTest;
- private boolean setStarted = false;
- private Stack stack;
- private NodePointer currentNodePointer;
- private boolean includeSelf;
- private static final NodeTest ELEMENT_NODE_TEST =
- new NodeTypeTest(Compiler.NODE_TYPE_NODE);
-
- 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) {
- if (!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;
- stack = new Stack();
- currentNodePointer = parentContext.getCurrentNodePointer();
- if (currentNodePointer != null) {
- if (!currentNodePointer.isLeaf()) {
- stack.push(
- currentNodePointer.childIterator(
- ELEMENT_NODE_TEST,
- false,
- null));
- }
- if (includeSelf) {
- if (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.
- */
- 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;
- }
- }