| /* |
| * 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: UnionPathIterator.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.DTMIterator; |
| import org.apache.xpath.Expression; |
| import org.apache.xpath.ExpressionOwner; |
| import org.apache.xpath.XPathVisitor; |
| import org.apache.xpath.compiler.Compiler; |
| import org.apache.xpath.compiler.OpCodes; |
| import org.apache.xpath.compiler.OpMap; |
| |
| /** |
| * This class extends NodeSetDTM, which implements DTMIterator, |
| * and fetches nodes one at a time in document order based on a XPath |
| * <a href="http://www.w3.org/TR/xpath#NT-UnionExpr">UnionExpr</a>. |
| * As each node is iterated via nextNode(), the node is also stored |
| * in the NodeVector, so that previousNode() can easily be done. |
| * @xsl.usage advanced |
| */ |
| public class UnionPathIterator extends LocPathIterator |
| implements Cloneable, DTMIterator, java.io.Serializable, PathComponent |
| { |
| static final long serialVersionUID = -3910351546843826781L; |
| |
| /** |
| * Constructor to create an instance which you can add location paths to. |
| */ |
| public UnionPathIterator() |
| { |
| |
| super(); |
| |
| // m_mutable = false; |
| // m_cacheNodes = false; |
| m_iterators = null; |
| m_exprs = null; |
| } |
| |
| /** |
| * 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); |
| |
| try |
| { |
| if (null != m_exprs) |
| { |
| int n = m_exprs.length; |
| DTMIterator newIters[] = new DTMIterator[n]; |
| |
| for (int i = 0; i < n; i++) |
| { |
| DTMIterator iter = m_exprs[i].asIterator(m_execContext, context); |
| newIters[i] = iter; |
| iter.nextNode(); |
| } |
| m_iterators = newIters; |
| } |
| } |
| catch(Exception e) |
| { |
| throw new org.apache.xml.utils.WrappedRuntimeException(e); |
| } |
| } |
| |
| /** |
| * Add an iterator to the union list. |
| * |
| * @param expr non-null reference to a location path iterator. |
| */ |
| public void addIterator(DTMIterator expr) |
| { |
| |
| // Increase array size by only 1 at a time. Fix this |
| // if it looks to be a problem. |
| if (null == m_iterators) |
| { |
| m_iterators = new DTMIterator[1]; |
| m_iterators[0] = expr; |
| } |
| else |
| { |
| DTMIterator[] exprs = m_iterators; |
| int len = m_iterators.length; |
| |
| m_iterators = new DTMIterator[len + 1]; |
| |
| System.arraycopy(exprs, 0, m_iterators, 0, len); |
| |
| m_iterators[len] = expr; |
| } |
| expr.nextNode(); |
| if(expr instanceof Expression) |
| ((Expression)expr).exprSetParent(this); |
| } |
| |
| /** |
| * 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 && null != m_iterators){ |
| int n = m_iterators.length; |
| for(int i = 0; i < n; i++) |
| { |
| m_iterators[i].detach(); |
| } |
| m_iterators = null; |
| } |
| } |
| |
| |
| /** |
| * Create a UnionPathIterator object, including creation |
| * of location path iterators from the opcode list, and call back |
| * into the Compiler to create predicate expressions. |
| * |
| * @param compiler The Compiler which is creating |
| * this expression. |
| * @param opPos The position of this iterator in the |
| * opcode list from the compiler. |
| * |
| * @throws javax.xml.transform.TransformerException |
| */ |
| public UnionPathIterator(Compiler compiler, int opPos) |
| throws javax.xml.transform.TransformerException |
| { |
| |
| super(); |
| |
| opPos = OpMap.getFirstChildPos(opPos); |
| |
| loadLocationPaths(compiler, opPos, 0); |
| } |
| |
| /** |
| * This will return an iterator capable of handling the union of paths given. |
| * |
| * @param compiler The Compiler which is creating |
| * this expression. |
| * @param opPos The position of this iterator in the |
| * opcode list from the compiler. |
| * |
| * @return Object that is derived from LocPathIterator. |
| * |
| * @throws javax.xml.transform.TransformerException |
| */ |
| public static LocPathIterator createUnionIterator(Compiler compiler, int opPos) |
| throws javax.xml.transform.TransformerException |
| { |
| // For the moment, I'm going to first create a full UnionPathIterator, and |
| // then see if I can reduce it to a UnionChildIterator. It would obviously |
| // be more effecient to just test for the conditions for a UnionChildIterator, |
| // and then create that directly. |
| UnionPathIterator upi = new UnionPathIterator(compiler, opPos); |
| int nPaths = upi.m_exprs.length; |
| boolean isAllChildIterators = true; |
| for(int i = 0; i < nPaths; i++) |
| { |
| LocPathIterator lpi = upi.m_exprs[i]; |
| |
| if(lpi.getAxis() != Axis.CHILD) |
| { |
| isAllChildIterators = false; |
| break; |
| } |
| else |
| { |
| // check for positional predicates or position function, which won't work. |
| if(HasPositionalPredChecker.check(lpi)) |
| { |
| isAllChildIterators = false; |
| break; |
| } |
| } |
| } |
| if(isAllChildIterators) |
| { |
| UnionChildIterator uci = new UnionChildIterator(); |
| |
| for(int i = 0; i < nPaths; i++) |
| { |
| PredicatedNodeTest lpi = upi.m_exprs[i]; |
| // I could strip the lpi down to a pure PredicatedNodeTest, but |
| // I don't think it's worth it. Note that the test can be used |
| // as a static object... so it doesn't have to be cloned. |
| uci.addNodeTest(lpi); |
| } |
| return uci; |
| |
| } |
| else |
| return upi; |
| } |
| |
| /** |
| * Get the analysis bits for this walker, as defined in the WalkerFactory. |
| * @return One of WalkerFactory#BIT_DESCENDANT, etc. |
| */ |
| public int getAnalysisBits() |
| { |
| int bits = 0; |
| |
| if (m_exprs != null) |
| { |
| int n = m_exprs.length; |
| |
| for (int i = 0; i < n; i++) |
| { |
| int bit = m_exprs[i].getAnalysisBits(); |
| bits |= bit; |
| } |
| } |
| |
| return bits; |
| } |
| |
| /** |
| * Read the object from a serialization stream. |
| * |
| * @param stream Input stream to read from |
| * |
| * @throws java.io.IOException |
| * @throws javax.xml.transform.TransformerException |
| */ |
| private void readObject(java.io.ObjectInputStream stream) |
| throws java.io.IOException, javax.xml.transform.TransformerException |
| { |
| try |
| { |
| stream.defaultReadObject(); |
| m_clones = new IteratorPool(this); |
| } |
| catch (ClassNotFoundException cnfe) |
| { |
| throw new javax.xml.transform.TransformerException(cnfe); |
| } |
| } |
| |
| /** |
| * Get a cloned LocPathIterator that holds the same |
| * position as this iterator. |
| * |
| * @return A clone of this iterator that holds the same node position. |
| * |
| * @throws CloneNotSupportedException |
| */ |
| public Object clone() throws CloneNotSupportedException |
| { |
| |
| UnionPathIterator clone = (UnionPathIterator) super.clone(); |
| if (m_iterators != null) |
| { |
| int n = m_iterators.length; |
| |
| clone.m_iterators = new DTMIterator[n]; |
| |
| for (int i = 0; i < n; i++) |
| { |
| clone.m_iterators[i] = (DTMIterator)m_iterators[i].clone(); |
| } |
| } |
| |
| return clone; |
| } |
| |
| |
| /** |
| * Create a new location path iterator. |
| * |
| * @param compiler The Compiler which is creating |
| * this expression. |
| * @param opPos The position of this iterator in the |
| * |
| * @return New location path iterator. |
| * |
| * @throws javax.xml.transform.TransformerException |
| */ |
| protected LocPathIterator createDTMIterator( |
| Compiler compiler, int opPos) throws javax.xml.transform.TransformerException |
| { |
| LocPathIterator lpi = (LocPathIterator)WalkerFactory.newDTMIterator(compiler, opPos, |
| (compiler.getLocationPathDepth() <= 0)); |
| return lpi; |
| } |
| |
| /** |
| * Initialize the location path iterators. Recursive. |
| * |
| * @param compiler The Compiler which is creating |
| * this expression. |
| * @param opPos The position of this iterator in the |
| * opcode list from the compiler. |
| * @param count The insert position of the iterator. |
| * |
| * @throws javax.xml.transform.TransformerException |
| */ |
| protected void loadLocationPaths(Compiler compiler, int opPos, int count) |
| throws javax.xml.transform.TransformerException |
| { |
| |
| // TODO: Handle unwrapped FilterExpr |
| int steptype = compiler.getOp(opPos); |
| |
| if (steptype == OpCodes.OP_LOCATIONPATH) |
| { |
| loadLocationPaths(compiler, compiler.getNextOpPos(opPos), count + 1); |
| |
| m_exprs[count] = createDTMIterator(compiler, opPos); |
| m_exprs[count].exprSetParent(this); |
| } |
| else |
| { |
| |
| // Have to check for unwrapped functions, which the LocPathIterator |
| // doesn't handle. |
| switch (steptype) |
| { |
| case OpCodes.OP_VARIABLE : |
| case OpCodes.OP_EXTFUNCTION : |
| case OpCodes.OP_FUNCTION : |
| case OpCodes.OP_GROUP : |
| loadLocationPaths(compiler, compiler.getNextOpPos(opPos), count + 1); |
| |
| WalkingIterator iter = |
| new WalkingIterator(compiler.getNamespaceContext()); |
| iter.exprSetParent(this); |
| |
| if(compiler.getLocationPathDepth() <= 0) |
| iter.setIsTopLevel(true); |
| |
| iter.m_firstWalker = new org.apache.xpath.axes.FilterExprWalker(iter); |
| |
| iter.m_firstWalker.init(compiler, opPos, steptype); |
| |
| m_exprs[count] = iter; |
| break; |
| default : |
| m_exprs = new LocPathIterator[count]; |
| } |
| } |
| } |
| |
| /** |
| * Returns the next node in the set and advances the position of the |
| * iterator in the set. After a DTMIterator 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. |
| */ |
| public int nextNode() |
| { |
| if(m_foundLast) |
| return DTM.NULL; |
| |
| // Loop through the iterators getting the current fetched |
| // node, and get the earliest occuring in document order |
| int earliestNode = DTM.NULL; |
| |
| if (null != m_iterators) |
| { |
| int n = m_iterators.length; |
| int iteratorUsed = -1; |
| |
| for (int i = 0; i < n; i++) |
| { |
| int node = m_iterators[i].getCurrentNode(); |
| |
| if (DTM.NULL == node) |
| continue; |
| else if (DTM.NULL == earliestNode) |
| { |
| iteratorUsed = i; |
| earliestNode = node; |
| } |
| else |
| { |
| if (node == earliestNode) |
| { |
| |
| // Found a duplicate, so skip past it. |
| m_iterators[i].nextNode(); |
| } |
| else |
| { |
| DTM dtm = getDTM(node); |
| |
| if (dtm.isNodeAfter(node, earliestNode)) |
| { |
| iteratorUsed = i; |
| earliestNode = node; |
| } |
| } |
| } |
| } |
| |
| if (DTM.NULL != earliestNode) |
| { |
| m_iterators[iteratorUsed].nextNode(); |
| |
| incrementCurrentPos(); |
| } |
| else |
| m_foundLast = true; |
| } |
| |
| m_lastFetched = earliestNode; |
| |
| return earliestNode; |
| } |
| |
| /** |
| * 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) |
| { |
| for (int i = 0; i < m_exprs.length; i++) |
| { |
| m_exprs[i].fixupVariables(vars, globalsSize); |
| } |
| |
| } |
| |
| /** |
| * The location path iterators, one for each |
| * <a href="http://www.w3.org/TR/xpath#NT-LocationPath">location |
| * path</a> contained in the union expression. |
| * @serial |
| */ |
| protected LocPathIterator[] m_exprs; |
| |
| |
| /** |
| * The location path iterators, one for each |
| * <a href="http://www.w3.org/TR/xpath#NT-LocationPath">location |
| * path</a> contained in the union expression. |
| * @serial |
| */ |
| protected DTMIterator[] m_iterators; |
| |
| /** |
| * 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() |
| { |
| // Could be smarter. |
| return -1; |
| } |
| |
| class iterOwner implements ExpressionOwner |
| { |
| int m_index; |
| |
| iterOwner(int index) |
| { |
| m_index = index; |
| } |
| |
| /** |
| * @see ExpressionOwner#getExpression() |
| */ |
| public Expression getExpression() |
| { |
| return m_exprs[m_index]; |
| } |
| |
| /** |
| * @see ExpressionOwner#setExpression(Expression) |
| */ |
| public void setExpression(Expression exp) |
| { |
| |
| if(!(exp instanceof LocPathIterator)) |
| { |
| // Yuck. Need FilterExprIter. Or make it so m_exprs can be just |
| // plain expressions? |
| WalkingIterator wi = new WalkingIterator(getPrefixResolver()); |
| FilterExprWalker few = new FilterExprWalker(wi); |
| wi.setFirstWalker(few); |
| few.setInnerExpression(exp); |
| wi.exprSetParent(UnionPathIterator.this); |
| few.exprSetParent(wi); |
| exp.exprSetParent(few); |
| exp = wi; |
| } |
| else |
| exp.exprSetParent(UnionPathIterator.this); |
| m_exprs[m_index] = (LocPathIterator)exp; |
| } |
| |
| } |
| |
| /** |
| * @see org.apache.xpath.XPathVisitable#callVisitors(ExpressionOwner, XPathVisitor) |
| */ |
| public void callVisitors(ExpressionOwner owner, XPathVisitor visitor) |
| { |
| if(visitor.visitUnionPath(owner, this)) |
| { |
| if(null != m_exprs) |
| { |
| int n = m_exprs.length; |
| for(int i = 0; i < n; i++) |
| { |
| m_exprs[i].callVisitors(new iterOwner(i), visitor); |
| } |
| } |
| } |
| } |
| |
| /** |
| * @see Expression#deepEquals(Expression) |
| */ |
| public boolean deepEquals(Expression expr) |
| { |
| if (!super.deepEquals(expr)) |
| return false; |
| |
| UnionPathIterator upi = (UnionPathIterator) expr; |
| |
| if (null != m_exprs) |
| { |
| int n = m_exprs.length; |
| |
| if((null == upi.m_exprs) || (upi.m_exprs.length != n)) |
| return false; |
| |
| for (int i = 0; i < n; i++) |
| { |
| if(!m_exprs[i].deepEquals(upi.m_exprs[i])) |
| return false; |
| } |
| } |
| else if (null != upi.m_exprs) |
| { |
| return false; |
| } |
| |
| return true; |
| } |
| |
| |
| } |