| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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. |
| */ |
| /* |
| * $Id: DescendantIterator.java 469314 2006-10-30 23:31:59Z minchau $ |
| */ |
| package org.apache.xpath.axes; |
| |
| import org.apache.xml.dtm.Axis; |
| import org.apache.xml.dtm.DTM; |
| import org.apache.xml.dtm.DTMAxisTraverser; |
| import org.apache.xml.dtm.DTMFilter; |
| import org.apache.xml.dtm.DTMIterator; |
| import org.apache.xpath.Expression; |
| import org.apache.xpath.XPathContext; |
| import org.apache.xpath.compiler.Compiler; |
| import org.apache.xpath.compiler.OpCodes; |
| import org.apache.xpath.compiler.OpMap; |
| import org.apache.xpath.patterns.NodeTest; |
| |
| /** |
| * This class implements an optimized iterator for |
| * descendant, descendant-or-self, or "//foo" patterns. |
| * @see org.apache.xpath.axes.LocPathIterator |
| * @xsl.usage advanced |
| */ |
| public class DescendantIterator extends LocPathIterator |
| { |
| static final long serialVersionUID = -1190338607743976938L; |
| /** |
| * Create a DescendantIterator object. |
| * |
| * @param compiler A reference to the Compiler that contains the op map. |
| * @param opPos The position within the op map, which contains the |
| * location path expression for this itterator. |
| * |
| * @throws javax.xml.transform.TransformerException |
| */ |
| DescendantIterator(Compiler compiler, int opPos, int analysis) |
| throws javax.xml.transform.TransformerException |
| { |
| |
| super(compiler, opPos, analysis, false); |
| |
| int firstStepPos = OpMap.getFirstChildPos(opPos); |
| int stepType = compiler.getOp(firstStepPos); |
| |
| boolean orSelf = (OpCodes.FROM_DESCENDANTS_OR_SELF == stepType); |
| boolean fromRoot = false; |
| if (OpCodes.FROM_SELF == stepType) |
| { |
| orSelf = true; |
| // firstStepPos += 8; |
| } |
| else if(OpCodes.FROM_ROOT == stepType) |
| { |
| fromRoot = true; |
| // Ugly code... will go away when AST work is done. |
| int nextStepPos = compiler.getNextStepPos(firstStepPos); |
| if(compiler.getOp(nextStepPos) == OpCodes.FROM_DESCENDANTS_OR_SELF) |
| orSelf = true; |
| // firstStepPos += 8; |
| } |
| |
| // Find the position of the last step. |
| int nextStepPos = firstStepPos; |
| while(true) |
| { |
| nextStepPos = compiler.getNextStepPos(nextStepPos); |
| if(nextStepPos > 0) |
| { |
| int stepOp = compiler.getOp(nextStepPos); |
| if(OpCodes.ENDOP != stepOp) |
| firstStepPos = nextStepPos; |
| else |
| break; |
| } |
| else |
| break; |
| |
| } |
| |
| // Fix for http://nagoya.apache.org/bugzilla/show_bug.cgi?id=1336 |
| if((analysis & WalkerFactory.BIT_CHILD) != 0) |
| orSelf = false; |
| |
| if(fromRoot) |
| { |
| if(orSelf) |
| m_axis = Axis.DESCENDANTSORSELFFROMROOT; |
| else |
| m_axis = Axis.DESCENDANTSFROMROOT; |
| } |
| else if(orSelf) |
| m_axis = Axis.DESCENDANTORSELF; |
| else |
| m_axis = Axis.DESCENDANT; |
| |
| int whatToShow = compiler.getWhatToShow(firstStepPos); |
| |
| if ((0 == (whatToShow |
| & (DTMFilter.SHOW_ATTRIBUTE | DTMFilter.SHOW_ELEMENT |
| | DTMFilter.SHOW_PROCESSING_INSTRUCTION))) || |
| (whatToShow == DTMFilter.SHOW_ALL)) |
| initNodeTest(whatToShow); |
| else |
| { |
| initNodeTest(whatToShow, compiler.getStepNS(firstStepPos), |
| compiler.getStepLocalName(firstStepPos)); |
| } |
| initPredicateInfo(compiler, firstStepPos); |
| } |
| |
| /** |
| * Create a DescendantIterator object. |
| * |
| */ |
| public DescendantIterator() |
| { |
| super(null); |
| m_axis = Axis.DESCENDANTSORSELFFROMROOT; |
| int whatToShow = DTMFilter.SHOW_ALL; |
| initNodeTest(whatToShow); |
| } |
| |
| |
| /** |
| * Get a cloned Iterator that is reset to the beginning |
| * of the query. |
| * |
| * @return A cloned NodeIterator set of the start of the query. |
| * |
| * @throws CloneNotSupportedException |
| */ |
| public DTMIterator cloneWithReset() throws CloneNotSupportedException |
| { |
| |
| DescendantIterator clone = (DescendantIterator) super.cloneWithReset(); |
| clone.m_traverser = m_traverser; |
| |
| clone.resetProximityPositions(); |
| |
| return clone; |
| } |
| |
| /** |
| * Returns the next node in the set and advances the position of the |
| * iterator in the set. After a NodeIterator is created, the first call |
| * to nextNode() returns the first node in the set. |
| * |
| * @return The next <code>Node</code> in the set being iterated over, or |
| * <code>null</code> if there are no more members in that set. |
| * |
| * @throws DOMException |
| * INVALID_STATE_ERR: Raised if this method is called after the |
| * <code>detach</code> method was invoked. |
| */ |
| public int nextNode() |
| { |
| if(m_foundLast) |
| return DTM.NULL; |
| |
| if(DTM.NULL == m_lastFetched) |
| { |
| resetProximityPositions(); |
| } |
| |
| int next; |
| |
| org.apache.xpath.VariableStack vars; |
| int savedStart; |
| if (-1 != m_stackFrame) |
| { |
| vars = m_execContext.getVarStack(); |
| |
| // These three statements need to be combined into one operation. |
| savedStart = vars.getStackFrame(); |
| |
| vars.setStackFrame(m_stackFrame); |
| } |
| else |
| { |
| // Yuck. Just to shut up the compiler! |
| vars = null; |
| savedStart = 0; |
| } |
| |
| try |
| { |
| do |
| { |
| if(0 == m_extendedTypeID) |
| { |
| next = m_lastFetched = (DTM.NULL == m_lastFetched) |
| ? m_traverser.first(m_context) |
| : m_traverser.next(m_context, m_lastFetched); |
| } |
| else |
| { |
| next = m_lastFetched = (DTM.NULL == m_lastFetched) |
| ? m_traverser.first(m_context, m_extendedTypeID) |
| : m_traverser.next(m_context, m_lastFetched, |
| m_extendedTypeID); |
| } |
| |
| if (DTM.NULL != next) |
| { |
| if(DTMIterator.FILTER_ACCEPT == acceptNode(next)) |
| break; |
| else |
| continue; |
| } |
| else |
| break; |
| } |
| while (next != DTM.NULL); |
| |
| if (DTM.NULL != next) |
| { |
| m_pos++; |
| return next; |
| } |
| else |
| { |
| m_foundLast = true; |
| |
| return DTM.NULL; |
| } |
| } |
| finally |
| { |
| if (-1 != m_stackFrame) |
| { |
| // These two statements need to be combined into one operation. |
| vars.setStackFrame(savedStart); |
| } |
| } |
| } |
| |
| /** |
| * Initialize the context values for this expression |
| * after it is cloned. |
| * |
| * @param context The XPath runtime context for this |
| * transformation. |
| */ |
| public void setRoot(int context, Object environment) |
| { |
| super.setRoot(context, environment); |
| m_traverser = m_cdtm.getAxisTraverser(m_axis); |
| |
| String localName = getLocalName(); |
| String namespace = getNamespace(); |
| int what = m_whatToShow; |
| // System.out.println("what: "); |
| // NodeTest.debugWhatToShow(what); |
| if(DTMFilter.SHOW_ALL == what |
| || NodeTest.WILD.equals(localName) |
| || NodeTest.WILD.equals(namespace)) |
| { |
| m_extendedTypeID = 0; |
| } |
| else |
| { |
| int type = getNodeTypeTest(what); |
| m_extendedTypeID = m_cdtm.getExpandedTypeID(namespace, localName, type); |
| } |
| |
| } |
| |
| /** |
| * Return the first node out of the nodeset, if this expression is |
| * a nodeset expression. This is the default implementation for |
| * nodesets. |
| * <p>WARNING: Do not mutate this class from this function!</p> |
| * @param xctxt The XPath runtime context. |
| * @return the first node out of the nodeset, or DTM.NULL. |
| */ |
| public int asNode(XPathContext xctxt) |
| throws javax.xml.transform.TransformerException |
| { |
| if(getPredicateCount() > 0) |
| return super.asNode(xctxt); |
| |
| int current = xctxt.getCurrentNode(); |
| |
| DTM dtm = xctxt.getDTM(current); |
| DTMAxisTraverser traverser = dtm.getAxisTraverser(m_axis); |
| |
| String localName = getLocalName(); |
| String namespace = getNamespace(); |
| int what = m_whatToShow; |
| |
| // System.out.print(" (DescendantIterator) "); |
| |
| // System.out.println("what: "); |
| // NodeTest.debugWhatToShow(what); |
| if(DTMFilter.SHOW_ALL == what |
| || localName == NodeTest.WILD |
| || namespace == NodeTest.WILD) |
| { |
| return traverser.first(current); |
| } |
| else |
| { |
| int type = getNodeTypeTest(what); |
| int extendedType = dtm.getExpandedTypeID(namespace, localName, type); |
| return traverser.first(current, extendedType); |
| } |
| } |
| |
| /** |
| * Detaches the iterator from the set which it iterated over, releasing |
| * any computational resources and placing the iterator in the INVALID |
| * state. After<code>detach</code> has been invoked, calls to |
| * <code>nextNode</code> or<code>previousNode</code> will raise the |
| * exception INVALID_STATE_ERR. |
| */ |
| public void detach() |
| { |
| if (m_allowDetach) { |
| m_traverser = null; |
| m_extendedTypeID = 0; |
| |
| // Always call the superclass detach last! |
| super.detach(); |
| } |
| } |
| |
| /** |
| * Returns the axis being iterated, if it is known. |
| * |
| * @return Axis.CHILD, etc., or -1 if the axis is not known or is of multiple |
| * types. |
| */ |
| public int getAxis() |
| { |
| return m_axis; |
| } |
| |
| |
| /** The traverser to use to navigate over the descendants. */ |
| transient protected DTMAxisTraverser m_traverser; |
| |
| /** The axis that we are traversing. */ |
| protected int m_axis; |
| |
| /** The extended type ID, not set until setRoot. */ |
| protected int m_extendedTypeID; |
| |
| /** |
| * @see Expression#deepEquals(Expression) |
| */ |
| public boolean deepEquals(Expression expr) |
| { |
| if(!super.deepEquals(expr)) |
| return false; |
| |
| if(m_axis != ((DescendantIterator)expr).m_axis) |
| return false; |
| |
| return true; |
| } |
| |
| |
| } |