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.ri.Compiler;
020 import org.apache.commons.jxpath.ri.EvalContext;
021 import org.apache.commons.jxpath.ri.QName;
022 import org.apache.commons.jxpath.ri.compiler.NodeNameTest;
023 import org.apache.commons.jxpath.ri.compiler.NodeTest;
024 import org.apache.commons.jxpath.ri.compiler.NodeTypeTest;
025 import org.apache.commons.jxpath.ri.model.NodeIterator;
026 import org.apache.commons.jxpath.ri.model.NodePointer;
027
028 /**
029 * EvalContext that walks the "attribute::" axis.
030 *
031 * @author Dmitri Plotnikov
032 * @version $Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $
033 */
034 public class AttributeContext extends EvalContext {
035 private static final QName WILDCARD = new QName(null, "*");
036
037 private NodeTest nodeTest;
038 private boolean setStarted = false;
039 private NodeIterator iterator;
040 private NodePointer currentNodePointer;
041
042 /**
043 * Create a new AttributeContext.
044 * @param parentContext represents the previous step on the path
045 * @param nodeTest is the name of the attribute we are looking for
046 */
047 public AttributeContext(EvalContext parentContext, NodeTest nodeTest) {
048 super(parentContext);
049 this.nodeTest = nodeTest;
050 }
051
052 public NodePointer getCurrentNodePointer() {
053 return currentNodePointer;
054 }
055
056 public void reset() {
057 setStarted = false;
058 iterator = null;
059 super.reset();
060 }
061
062 public boolean setPosition(int position) {
063 if (position < getCurrentPosition()) {
064 reset();
065 }
066
067 while (getCurrentPosition() < position) {
068 if (!nextNode()) {
069 return false;
070 }
071 }
072 return true;
073 }
074
075 public boolean nextNode() {
076 super.setPosition(getCurrentPosition() + 1);
077 if (!setStarted) {
078 setStarted = true;
079 QName name;
080 if (nodeTest instanceof NodeNameTest) {
081 name = ((NodeNameTest) nodeTest).getNodeName();
082 }
083 else {
084 if (nodeTest instanceof NodeTypeTest
085 && ((NodeTypeTest) nodeTest).getNodeType() == Compiler.NODE_TYPE_NODE) {
086 name = WILDCARD;
087 }
088 else {
089 iterator = null;
090 return false;
091 }
092 }
093 iterator = parentContext.getCurrentNodePointer().attributeIterator(
094 name);
095 }
096 if (iterator == null) {
097 return false;
098 }
099 if (!iterator.setPosition(iterator.getPosition() + 1)) {
100 return false;
101 }
102 currentNodePointer = iterator.getNodePointer();
103 return true;
104 }
105 }