001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.commons.jxpath.ri.axes;
018
019 import org.apache.commons.jxpath.Pointer;
020 import org.apache.commons.jxpath.ri.EvalContext;
021 import org.apache.commons.jxpath.ri.compiler.NodeTest;
022 import org.apache.commons.jxpath.ri.model.NodePointer;
023
024 /**
025 * EvalContext that returns the current node from the parent context if the
026 * test succeeds.
027 *
028 * @author Dmitri Plotnikov
029 * @version $Revision: 670727 $ $Date: 2008-06-23 15:10:38 -0500 (Mon, 23 Jun 2008) $
030 */
031 public class SelfContext extends EvalContext {
032 private NodeTest nodeTest;
033 private boolean startedSet = false;
034 private NodePointer nodePointer;
035
036 /**
037 * Create a new SelfContext.
038 * @param parentContext EvalContext
039 * @param nodeTest guard
040 */
041 public SelfContext(EvalContext parentContext, NodeTest nodeTest) {
042 super(parentContext);
043 this.nodeTest = nodeTest;
044 }
045
046 public Pointer getSingleNodePointer() {
047 return parentContext.getSingleNodePointer();
048 }
049
050 public NodePointer getCurrentNodePointer() {
051 if (position == 0 && !setPosition(1)) {
052 return null;
053 }
054 return nodePointer;
055 }
056
057 public boolean nextNode() {
058 return setPosition(getCurrentPosition() + 1);
059 }
060
061 public void reset() {
062 super.reset();
063 startedSet = false;
064 }
065
066 public boolean setPosition(int position) {
067 if (position != 1) {
068 return false;
069 }
070 super.setPosition(position);
071 if (!startedSet) {
072 startedSet = true;
073 nodePointer = (NodePointer) parentContext.getCurrentNodePointer();
074 }
075
076 if (nodePointer == null) {
077 return false;
078 }
079
080 return nodeTest == null || nodePointer.testNode(nodeTest);
081 }
082 }