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: OneStepIteratorForward.java 469314 2006-10-30 23:31:59Z minchau $ 20 */ 21package org.apache.xpath.axes; 22 23import org.apache.xml.dtm.DTM; 24import org.apache.xml.dtm.DTMFilter; 25import org.apache.xpath.Expression; 26import org.apache.xpath.compiler.Compiler; 27import org.apache.xpath.compiler.OpMap; 28 29/** 30 * This class implements a general iterator for 31 * those LocationSteps with only one step, and perhaps a predicate, 32 * that only go forward (i.e. it can not be used with ancestors, 33 * preceding, etc.) 34 * @see org.apache.xpath.axes#ChildTestIterator 35 * @xsl.usage advanced 36 */ 37public class OneStepIteratorForward extends ChildTestIterator 38{ 39 static final long serialVersionUID = -1576936606178190566L; 40 /** The traversal axis from where the nodes will be filtered. */ 41 protected int m_axis = -1; 42 43 /** 44 * Create a OneStepIterator object. 45 * 46 * @param compiler A reference to the Compiler that contains the op map. 47 * @param opPos The position within the op map, which contains the 48 * location path expression for this itterator. 49 * 50 * @throws javax.xml.transform.TransformerException 51 */ 52 OneStepIteratorForward(Compiler compiler, int opPos, int analysis) 53 throws javax.xml.transform.TransformerException 54 { 55 super(compiler, opPos, analysis); 56 int firstStepPos = OpMap.getFirstChildPos(opPos); 57 58 m_axis = WalkerFactory.getAxisFromStep(compiler, firstStepPos); 59 60 } 61 62 /** 63 * Create a OneStepIterator object that will just traverse the self axes. 64 * 65 * @param axis One of the org.apache.xml.dtm.Axis integers. 66 * 67 * @throws javax.xml.transform.TransformerException 68 */ 69 public OneStepIteratorForward(int axis) 70 { 71 super(null); 72 73 m_axis = axis; 74 int whatToShow = DTMFilter.SHOW_ALL; 75 initNodeTest(whatToShow); 76 } 77 78 79 80 81 /** 82 * Initialize the context values for this expression 83 * after it is cloned. 84 * 85 * @param context The XPath runtime context for this 86 * transformation. 87 */ 88 public void setRoot(int context, Object environment) 89 { 90 super.setRoot(context, environment); 91 m_traverser = m_cdtm.getAxisTraverser(m_axis); 92 93 } 94 95// /** 96// * Return the first node out of the nodeset, if this expression is 97// * a nodeset expression. This is the default implementation for 98// * nodesets. 99// * <p>WARNING: Do not mutate this class from this function!</p> 100// * @param xctxt The XPath runtime context. 101// * @return the first node out of the nodeset, or DTM.NULL. 102// */ 103// public int asNode(XPathContext xctxt) 104// throws javax.xml.transform.TransformerException 105// { 106// if(getPredicateCount() > 0) 107// return super.asNode(xctxt); 108// 109// int current = xctxt.getCurrentNode(); 110// 111// DTM dtm = xctxt.getDTM(current); 112// DTMAxisTraverser traverser = dtm.getAxisTraverser(m_axis); 113// 114// String localName = getLocalName(); 115// String namespace = getNamespace(); 116// int what = m_whatToShow; 117// 118// // System.out.println("what: "); 119// // NodeTest.debugWhatToShow(what); 120// if(DTMFilter.SHOW_ALL == what 121// || ((DTMFilter.SHOW_ELEMENT & what) == 0) 122// || localName == NodeTest.WILD 123// || namespace == NodeTest.WILD) 124// { 125// return traverser.first(current); 126// } 127// else 128// { 129// int type = getNodeTypeTest(what); 130// int extendedType = dtm.getExpandedTypeID(namespace, localName, type); 131// return traverser.first(current, extendedType); 132// } 133// } 134 135 /** 136 * Get the next node via getFirstAttribute && getNextAttribute. 137 */ 138 protected int getNextNode() 139 { 140 m_lastFetched = (DTM.NULL == m_lastFetched) 141 ? m_traverser.first(m_context) 142 : m_traverser.next(m_context, m_lastFetched); 143 return m_lastFetched; 144 } 145 146 /** 147 * Returns the axis being iterated, if it is known. 148 * 149 * @return Axis.CHILD, etc., or -1 if the axis is not known or is of multiple 150 * types. 151 */ 152 public int getAxis() 153 { 154 return m_axis; 155 } 156 157 /** 158 * @see Expression#deepEquals(Expression) 159 */ 160 public boolean deepEquals(Expression expr) 161 { 162 if(!super.deepEquals(expr)) 163 return false; 164 165 if(m_axis != ((OneStepIteratorForward)expr).m_axis) 166 return false; 167 168 return true; 169 } 170 171 172} 173