| /* |
| * 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. |
| */ |
| /* |
| * $Id$ |
| */ |
| package org.apache.xpath.axes; |
| |
| import org.apache.xml.dtm.Axis; |
| import org.apache.xml.dtm.DTM; |
| import org.apache.xml.dtm.DTMIterator; |
| import org.apache.xpath.Expression; |
| import org.apache.xpath.ExpressionOwner; |
| import org.apache.xpath.XPathContext; |
| import org.apache.xpath.XPathVisitor; |
| import org.apache.xpath.compiler.Compiler; |
| import org.apache.xpath.compiler.OpCodes; |
| import org.apache.xpath.objects.XNodeSet; |
| |
| /** |
| * Walker for the OP_VARIABLE, or OP_EXTFUNCTION, or OP_FUNCTION, or OP_GROUP, |
| * op codes. |
| * @see <a href="http://www.w3.org/TR/xpath#NT-FilterExpr">XPath FilterExpr descriptions</a> |
| */ |
| public class FilterExprWalker extends AxesWalker |
| { |
| static final long serialVersionUID = 5457182471424488375L; |
| |
| /** |
| * Construct a FilterExprWalker using a LocPathIterator. |
| * |
| * @param locPathIterator non-null reference to the parent iterator. |
| */ |
| public FilterExprWalker(WalkingIterator locPathIterator) |
| { |
| super(locPathIterator, Axis.FILTEREDLIST); |
| } |
| |
| /** |
| * Init a FilterExprWalker. |
| * |
| * @param compiler non-null reference to the Compiler that is constructing. |
| * @param opPos positive opcode position for this step. |
| * @param stepType The type of step. |
| * |
| * @throws javax.xml.transform.TransformerException |
| */ |
| public void init(Compiler compiler, int opPos, int stepType) |
| throws javax.xml.transform.TransformerException |
| { |
| |
| super.init(compiler, opPos, stepType); |
| |
| // Smooth over an anomily in the opcode map... |
| switch (stepType) |
| { |
| case OpCodes.OP_FUNCTION : |
| case OpCodes.OP_EXTFUNCTION : |
| m_mustHardReset = true; |
| case OpCodes.OP_GROUP : |
| case OpCodes.OP_VARIABLE : |
| m_expr = compiler.compile(opPos); |
| m_expr.exprSetParent(this); |
| //if((OpCodes.OP_FUNCTION == stepType) && (m_expr instanceof org.apache.xalan.templates.FuncKey)) |
| if(m_expr instanceof org.apache.xpath.operations.Variable) |
| { |
| // hack/temp workaround |
| m_canDetachNodeset = false; |
| } |
| break; |
| default : |
| m_expr = compiler.compile(opPos + 2); |
| m_expr.exprSetParent(this); |
| } |
| // if(m_expr instanceof WalkingIterator) |
| // { |
| // WalkingIterator wi = (WalkingIterator)m_expr; |
| // if(wi.getFirstWalker() instanceof FilterExprWalker) |
| // { |
| // FilterExprWalker fw = (FilterExprWalker)wi.getFirstWalker(); |
| // if(null == fw.getNextWalker()) |
| // { |
| // m_expr = fw.m_expr; |
| // m_expr.exprSetParent(this); |
| // } |
| // } |
| // |
| // } |
| } |
| |
| /** |
| * Detaches the walker from the set which it iterated over, releasing |
| * any computational resources and placing the iterator in the INVALID |
| * state. |
| */ |
| public void detach() |
| { |
| super.detach(); |
| if (m_canDetachNodeset) |
| { |
| m_exprObj.detach(); |
| } |
| m_exprObj = null; |
| } |
| |
| /** |
| * Set the root node of the TreeWalker. |
| * |
| * @param root non-null reference to the root, or starting point of |
| * the query. |
| */ |
| public void setRoot(int root) |
| { |
| |
| super.setRoot(root); |
| |
| m_exprObj = FilterExprIteratorSimple.executeFilterExpr(root, |
| m_lpi.getXPathContext(), m_lpi.getPrefixResolver(), |
| m_lpi.getIsTopLevel(), m_lpi.m_stackFrame, m_expr); |
| |
| } |
| |
| /** |
| * Get a cloned FilterExprWalker. |
| * |
| * @return A new FilterExprWalker that can be used without mutating this one. |
| * |
| * @throws CloneNotSupportedException |
| */ |
| public Object clone() throws CloneNotSupportedException |
| { |
| |
| FilterExprWalker clone = (FilterExprWalker) super.clone(); |
| |
| if (null != m_exprObj) |
| clone.m_exprObj = (XNodeSet) m_exprObj.cloneWithReset(); |
| |
| return clone; |
| } |
| |
| /** |
| * This method needs to override AxesWalker.acceptNode because FilterExprWalkers |
| * don't need to, and shouldn't, do a node test. |
| * @param n The node to check to see if it passes the filter or not. |
| * @return a constant to determine whether the node is accepted, |
| * rejected, or skipped, as defined above . |
| */ |
| public short acceptNode(int n) |
| { |
| |
| try |
| { |
| if (getPredicateCount() > 0) |
| { |
| countProximityPosition(0); |
| |
| if (!executePredicates(n, m_lpi.getXPathContext())) |
| return DTMIterator.FILTER_SKIP; |
| } |
| |
| return DTMIterator.FILTER_ACCEPT; |
| } |
| catch (javax.xml.transform.TransformerException se) |
| { |
| throw new RuntimeException(se.getMessage()); |
| } |
| } |
| |
| /** |
| * Moves the <code>TreeWalker</code> to the next visible node in document |
| * order relative to the current node, and returns the new node. If the |
| * current node has no next node, or if the search for nextNode attempts |
| * to step upward from the TreeWalker's root node, returns |
| * <code>null</code> , and retains the current node. |
| * @return The new node, or <code>null</code> if the current node has no |
| * next node in the TreeWalker's logical view. |
| */ |
| public int getNextNode() |
| { |
| |
| if (null != m_exprObj) |
| { |
| int next = m_exprObj.nextNode(); |
| return next; |
| } |
| else |
| return DTM.NULL; |
| } |
| |
| /** |
| * Get the index of the last node that can be itterated to. |
| * |
| * |
| * @param xctxt XPath runtime context. |
| * |
| * @return the index of the last node that can be itterated to. |
| */ |
| public int getLastPos(XPathContext xctxt) |
| { |
| return m_exprObj.getLength(); |
| } |
| |
| /** The contained expression. Should be non-null. |
| * @serial */ |
| private Expression m_expr; |
| |
| /** The result of executing m_expr. Needs to be deep cloned on clone op. */ |
| transient private XNodeSet m_exprObj; |
| |
| private boolean m_mustHardReset = false; |
| private boolean m_canDetachNodeset = true; |
| |
| /** |
| * This function is used to fixup variables from QNames to stack frame |
| * indexes at stylesheet build time. |
| * @param vars List of QNames that correspond to variables. This list |
| * should be searched backwards for the first qualified name that |
| * corresponds to the variable reference qname. The position of the |
| * QName in the vector from the start of the vector will be its position |
| * in the stack frame (but variables above the globalsTop value will need |
| * to be offset to the current stack frame). |
| */ |
| public void fixupVariables(java.util.Vector vars, int globalsSize) |
| { |
| super.fixupVariables(vars, globalsSize); |
| m_expr.fixupVariables(vars, globalsSize); |
| } |
| |
| /** |
| * Get the inner contained expression of this filter. |
| */ |
| public Expression getInnerExpression() |
| { |
| return m_expr; |
| } |
| |
| /** |
| * Set the inner contained expression of this filter. |
| */ |
| public void setInnerExpression(Expression expr) |
| { |
| expr.exprSetParent(this); |
| m_expr = expr; |
| } |
| |
| |
| /** |
| * Get the analysis bits for this walker, as defined in the WalkerFactory. |
| * @return One of WalkerFactory#BIT_DESCENDANT, etc. |
| */ |
| public int getAnalysisBits() |
| { |
| if (null != m_expr && m_expr instanceof PathComponent) |
| { |
| return ((PathComponent) m_expr).getAnalysisBits(); |
| } |
| return WalkerFactory.BIT_FILTER; |
| } |
| |
| /** |
| * Returns true if all the nodes in the iteration well be returned in document |
| * order. |
| * Warning: This can only be called after setRoot has been called! |
| * |
| * @return true as a default. |
| */ |
| public boolean isDocOrdered() |
| { |
| return m_exprObj.isDocOrdered(); |
| } |
| |
| /** |
| * 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_exprObj.getAxis(); |
| } |
| |
| class filterExprOwner implements ExpressionOwner |
| { |
| /** |
| * @see ExpressionOwner#getExpression() |
| */ |
| public Expression getExpression() |
| { |
| return m_expr; |
| } |
| |
| /** |
| * @see ExpressionOwner#setExpression(Expression) |
| */ |
| public void setExpression(Expression exp) |
| { |
| exp.exprSetParent(FilterExprWalker.this); |
| m_expr = exp; |
| } |
| } |
| |
| /** |
| * This will traverse the heararchy, calling the visitor for |
| * each member. If the called visitor method returns |
| * false, the subtree should not be called. |
| * |
| * @param visitor The visitor whose appropriate method will be called. |
| */ |
| public void callPredicateVisitors(XPathVisitor visitor) |
| { |
| m_expr.callVisitors(new filterExprOwner(), visitor); |
| |
| super.callPredicateVisitors(visitor); |
| } |
| |
| |
| /** |
| * @see Expression#deepEquals(Expression) |
| */ |
| public boolean deepEquals(Expression expr) |
| { |
| if (!super.deepEquals(expr)) |
| return false; |
| |
| FilterExprWalker walker = (FilterExprWalker)expr; |
| if(!m_expr.deepEquals(walker.m_expr)) |
| return false; |
| |
| return true; |
| } |
| |
| |
| |
| } |