- /*
- * Copyright 1999-2004 The Apache Software Foundation.
- *
- * Licensed 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,v 1.33 2004/02/17 04:32:08 minchau Exp $
- */
- package com.sun.org.apache.xpath.internal.axes;
-
- import com.sun.org.apache.xml.internal.dtm.Axis;
- import com.sun.org.apache.xml.internal.dtm.DTM;
- import com.sun.org.apache.xml.internal.dtm.DTMIterator;
- import com.sun.org.apache.xpath.internal.Expression;
- import com.sun.org.apache.xpath.internal.ExpressionOwner;
- import com.sun.org.apache.xpath.internal.XPathVisitor;
- import com.sun.org.apache.xpath.internal.compiler.Compiler;
- import com.sun.org.apache.xpath.internal.compiler.OpCodes;
-
- /**
- * 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
- {
-
- /**
- * 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 execContext 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 com.sun.org.apache.xml.internal.utils.WrappedRuntimeException(e);
- }
- }
-
- /**
- * Add an iterator to the union list.
- *
- * @param iter 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 = compiler.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 LocPathIterator[n];
- //
- // for (int i = 0; i < n; i++)
- // {
- // clone.m_iterators[i] = (LocPathIterator)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 com.sun.org.apache.xpath.internal.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 com.sun.org.apache.xpath.internal.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;
- }
-
-
- }