1/* 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18/* 19 * $Id: SelfIteratorNoPredicate.java 469263 2006-10-30 20:45:40Z minchau $ 20 */ 21package org.apache.xpath.axes; 22 23import org.apache.xml.dtm.DTM; 24import org.apache.xpath.XPathContext; 25import org.apache.xpath.compiler.Compiler; 26 27/** 28 * This class implements an optimized iterator for 29 * "." patterns, that is, the self axes without any predicates. 30 * @see org.apache.xpath.axes.LocPathIterator 31 * @xsl.usage advanced 32 */ 33public class SelfIteratorNoPredicate extends LocPathIterator 34{ 35 static final long serialVersionUID = -4226887905279814201L; 36 37 /** 38 * Create a SelfIteratorNoPredicate object. 39 * 40 * @param compiler A reference to the Compiler that contains the op map. 41 * @param opPos The position within the op map, which contains the 42 * location path expression for this itterator. 43 * @param analysis Analysis bits. 44 * 45 * @throws javax.xml.transform.TransformerException 46 */ 47 SelfIteratorNoPredicate(Compiler compiler, int opPos, int analysis) 48 throws javax.xml.transform.TransformerException 49 { 50 super(compiler, opPos, analysis, false); 51 } 52 53 /** 54 * Create a SelfIteratorNoPredicate object. 55 * 56 * @throws javax.xml.transform.TransformerException 57 */ 58 public SelfIteratorNoPredicate() 59 throws javax.xml.transform.TransformerException 60 { 61 super(null); 62 } 63 64 65 /** 66 * Returns the next node in the set and advances the position of the 67 * iterator in the set. After a NodeIterator is created, the first call 68 * to nextNode() returns the first node in the set. 69 * 70 * @return The next <code>Node</code> in the set being iterated over, or 71 * <code>null</code> if there are no more members in that set. 72 */ 73 public int nextNode() 74 { 75 if (m_foundLast) 76 return DTM.NULL; 77 78 int next; 79 80 m_lastFetched = next = (DTM.NULL == m_lastFetched) 81 ? m_context 82 : DTM.NULL; 83 84 // m_lastFetched = next; 85 if (DTM.NULL != next) 86 { 87 m_pos++; 88 89 return next; 90 } 91 else 92 { 93 m_foundLast = true; 94 95 return DTM.NULL; 96 } 97 } 98 99 /** 100 * Return the first node out of the nodeset, if this expression is 101 * a nodeset expression. This is the default implementation for 102 * nodesets. Derived classes should try and override this and return a 103 * value without having to do a clone operation. 104 * @param xctxt The XPath runtime context. 105 * @return the first node out of the nodeset, or DTM.NULL. 106 */ 107 public int asNode(XPathContext xctxt) 108 throws javax.xml.transform.TransformerException 109 { 110 return xctxt.getCurrentNode(); 111 } 112 113 /** 114 * Get the index of the last node that can be itterated to. 115 * This probably will need to be overridded by derived classes. 116 * 117 * @param xctxt XPath runtime context. 118 * 119 * @return the index of the last node that can be itterated to. 120 */ 121 public int getLastPos(XPathContext xctxt) 122 { 123 return 1; 124 } 125 126 127} 128