- /*
- * 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 org.apache.commons.jxpath.Pointer;
- 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;
-
- /**
- * EvalContext that can walk the "child::", "following-sibling::" and
- * "preceding-sibling::" axes.
- *
- * @author Dmitri Plotnikov
- * @version $Revision: 1.16 $ $Date: 2004/03/25 03:49:50 $
- */
- public class ChildContext extends EvalContext {
- private NodeTest nodeTest;
- private boolean startFromParentLocation;
- private boolean reverse;
- private NodeIterator iterator;
-
- public ChildContext(
- EvalContext parentContext,
- NodeTest nodeTest,
- boolean startFromParentLocation,
- boolean reverse)
- {
- super(parentContext);
- this.nodeTest = nodeTest;
- this.startFromParentLocation = startFromParentLocation;
- this.reverse = reverse;
- }
-
- public NodePointer getCurrentNodePointer() {
- if (position == 0) {
- if (!setPosition(1)) {
- return null;
- }
- }
- if (iterator != null) {
- return iterator.getNodePointer();
- }
- else {
- return null;
- }
- }
-
- /**
- * This method is called on the last context on the path when only
- * one value is needed. Note that this will return the whole property,
- * even if it is a collection. It will not extract the first element
- * of the collection. For example, "books" will return the collection
- * of books rather than the first book from that collection.
- */
- public Pointer getSingleNodePointer() {
- if (position == 0) {
- while (nextSet()) {
- prepare();
- if (iterator == null) {
- return null;
- }
- // See if there is a property there, singular or collection
- NodePointer pointer = iterator.getNodePointer();
- if (pointer != null) {
- return pointer;
- }
- }
- return null;
- }
- return getCurrentNodePointer();
- }
-
- public boolean nextNode() {
- return setPosition(getCurrentPosition() + 1);
- }
-
- public void reset() {
- super.reset();
- iterator = null;
- }
-
- public boolean setPosition(int position) {
- int oldPosition = getCurrentPosition();
- super.setPosition(position);
- if (oldPosition == 0) {
- prepare();
- }
- if (iterator == null) {
- return false;
- }
- return iterator.setPosition(position);
- }
-
- /**
- * Allocates a PropertyIterator.
- */
- private void prepare() {
- NodePointer parent = parentContext.getCurrentNodePointer();
- if (parent == null) {
- return;
- }
- if (startFromParentLocation) {
- NodePointer pointer = parent.getParent();
- iterator = pointer.childIterator(nodeTest, reverse, parent);
- }
- else {
- iterator = parent.childIterator(nodeTest, reverse, null);
- }
- }
- }