/*
* The Apache Software License, Version 1.1
*
*
* Copyright (c) 1999 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Xalan" and "Apache Software Foundation" must
* not be used to endorse or promote products derived from this
* software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
* nor may "Apache" appear in their name, without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation and was
* originally based on software copyright (c) 1999, Lotus
* Development Corporation., http://www.lotus.com. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
package org.apache.xpath.axes;
import org.apache.xpath.compiler.OpCodes;
// DOM Imports
//import org.w3c.dom.traversal.NodeIterator;
//import org.w3c.dom.Node;
//import org.w3c.dom.DOMException;
//import org.w3c.dom.traversal.NodeFilter;
import org.apache.xml.dtm.DTM;
import org.apache.xml.dtm.DTMIterator;
import org.apache.xml.dtm.DTMFilter;
import org.apache.xml.dtm.DTMManager;
import org.apache.xml.dtm.DTMIterator;
// Xalan Imports
import org.apache.xpath.NodeSetDTM;
import org.apache.xpath.Expression;
import org.apache.xpath.XPath;
import org.apache.xpath.XPathContext;
import org.apache.xpath.objects.XNodeSet;
import org.apache.xpath.objects.XObject;
import org.apache.xpath.compiler.Compiler;
import org.apache.xml.utils.ObjectPool;
/**
* <meta name="usage" content="advanced"/>
* 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.
*/
public class UnionPathIterator extends Expression
implements Cloneable, DTMIterator, java.io.Serializable
{
/**
* Constructor to create an instance which you can add location paths to.
*/
public UnionPathIterator()
{
super();
// m_mutable = false;
// m_cacheNodes = false;
m_iterators = 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)
{
this.m_execContext = (XPathContext)environment;
this.m_currentContextNode = context;
this.m_context = context;
m_lastFetched = DTM.NULL;
m_next = 0;
m_last = 0;
m_foundLast = false;
try
{
if (null != m_iterators)
{
int n = m_iterators.length;
for (int i = 0; i < n; i++)
{
m_iterators[i] = ((LocPathIterator)m_iterators[i]).asIterator(m_execContext, context);
m_iterators[i].setRoot(context, environment);
m_iterators[i].nextNode();
}
}
}
catch(Exception e)
{
throw new org.apache.xml.utils.WrappedRuntimeException(e);
}
}
/** Control over whether it is OK for detach to reset the iterator. */
private boolean m_allowDetach = true;
/**
* Specify if it's OK for detach to release the iterator for reuse.
*
* @param allowRelease true if it is OK for detach to release this iterator
* for pooling.
*/
public void allowDetachToRelease(boolean allowRelease)
{
m_allowDetach = allowRelease;
}
/**
* 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_cachedNodes = null;
m_execContext = null;
// m_prefixResolver = null;
// m_cdtm = null;
if (null != m_iterators)
{
int n = m_iterators.length;
for (int i = 0; i < n; i++)
{
m_iterators[i].detach();
}
}
// int n = m_iterators.length;
//
// for (int i = 0; i < n; i++)
// {
// m_iterators[i].detach();
// }
m_clones.freeInstance(this);
}
}
/** Pool of UnionPathIterators. (The need for this has to be re-evaluated. -sb) */
transient protected IteratorPool m_clones = new IteratorPool(this);
/**
* Execute this iterator, meaning create a clone that can
* store state, and initialize it for fast execution from
* the current runtime state. When this is called, no actual
* query from the current context node is performed.
*
* @param xctxt The XPath execution context.
*
* @return An XNodeSet reference that holds this iterator.
*
* @throws javax.xml.transform.TransformerException
*/
public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException
{
UnionPathIterator clone =
(UnionPathIterator) m_clones.getInstance();
int current = xctxt.getCurrentNode();
clone.setRoot(current, xctxt);
return new XNodeSet(clone);
}
/** If this iterator needs to cache nodes that are fetched, they
* are stored here. */
transient NodeSetDTM m_cachedNodes = null;
/** The index of the next node to be fetched. Useful if this
* is a cached iterator, and is being used as random access
* NodeList. */
transient protected int m_next = 0;
/**
* If setShouldCacheNodes(true) is called, then nodes will
* be cached. They are not cached by default.
*
* @param b True if this iterator should cache nodes.
*/
public void setShouldCacheNodes(boolean b)
{
if (b)
m_cachedNodes = new NodeSetDTM(getDTMManager());
else
m_cachedNodes = null;
}
/**
* Tells if this iterator can have nodes added to it or set via
* the <code>setItem(int node, int index)</code> method.
*
* @return True if the nodelist can be mutated.
*/
public boolean isMutable()
{
return (m_cachedNodes != null);
}
/**
* Set the current position in the node set.
* @param i Must be a valid index.
*/
public void setCurrentPos(int i)
{
if (null == m_cachedNodes)
throw new RuntimeException(
"This NodeSetDTM can not do indexing or counting functions!");
m_next = i;
m_cachedNodes.setCurrentPos(i);
}
/**
* Get the length of the list.
*
* @return The length of this list, or zero is this is not a cached list.
*/
public int size()
{
if (null == m_cachedNodes)
return 0;
return m_cachedNodes.size();
}
/**
* Tells if this NodeSetDTM is "fresh", in other words, if
* the first nextNode() that is called will return the
* first node in the set.
*
* @return True if the iteration has not yet begun.
*/
public boolean isFresh()
{
return (m_next == 0);
}
/**
* Returns the previous node in the set and moves the position of the
* iterator backwards in the set.
* @return The previous <code>Node</code> in the set being iterated over,
* or<code>null</code> if there are no more members in that set.
*/
public int previousNode()
{
if (null == m_cachedNodes)
throw new RuntimeException(
"This NodeSetDTM can not iterate to a previous node!");
return m_cachedNodes.previousNode();
}
/**
* This attribute determines which node types are presented via the
* iterator. The available set of constants is defined in the
* <code>DTMFilter</code> interface.
*
* @return A bit set that tells what node types to show (DTMFilter.SHOW_ALL at
* the iterator level).
*/
public int getWhatToShow()
{
// TODO: ??
return DTMFilter.SHOW_ALL & ~DTMFilter.SHOW_ENTITY_REFERENCE;
}
/**
* The filter used to screen nodes.
*
* @return null.
*/
public DTMFilter getFilter()
{
return null;
}
/**
* The root node of the Iterator, as specified when it was created.
*
* @return The context node of this iterator.
*/
public int getRoot()
{
return m_context;
}
/**
* The value of this flag determines whether the children of entity
* reference nodes are visible to the iterator. If false, they will be
* skipped over.
* <br> To produce a view of the document that has entity references
* expanded and does not expose the entity reference node itself, use the
* whatToShow flags to hide the entity reference node and set
* expandEntityReferences to true when creating the iterator. To produce
* a view of the document that has entity reference nodes but no entity
* expansion, use the whatToShow flags to show the entity reference node
* and set expandEntityReferences to false.
*
* @return true.
*/
public boolean getExpandEntityReferences()
{
return true;
}
/**
* Add an iterator to the union list.
*
* @param iter non-null reference to a location path iterator.
*/
public void addIterator(LocPathIterator iter)
{
// 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 LocPathIterator[1];
m_iterators[0] = iter;
}
else
{
DTMIterator[] iters = m_iterators;
int len = m_iterators.length;
m_iterators = new LocPathIterator[len + 1];
System.arraycopy(iters, 0, m_iterators, 0, len);
m_iterators[len] = iter;
}
}
/**
* 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);
}
/**
* 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 Iterator that is reset to the beginning
* of the query.
*
* @return A cloned DTMIterator set of the start of the query.
*
* @throws CloneNotSupportedException
*/
public DTMIterator cloneWithReset() throws CloneNotSupportedException
{
UnionPathIterator clone = (UnionPathIterator) clone();
clone.reset();
return clone;
}
/**
* 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;
}
/**
* <meta name="usage" content="experimental"/>
* Given an select expression and a context, evaluate the XPath
* and return the resulting iterator.
*
* @param xctxt The execution context.
* @param contextNode The node that "." expresses.
* @param namespaceContext The context in which namespaces in the
* XPath are supposed to be expanded.
*
* @throws TransformerException thrown if the active ProblemListener decides
* the error condition is severe enough to halt processing.
*
* @throws javax.xml.transform.TransformerException
*/
public DTMIterator asIterator(
XPathContext xctxt, int contextNode)
throws javax.xml.transform.TransformerException
{
UnionPathIterator clone = (UnionPathIterator)m_clones.getInstance();
clone.setRoot(contextNode, xctxt);
return clone;
}
/**
* Reset the iterator.
*/
public void reset()
{
// super.reset();
m_foundLast = false;
m_next = 0;
m_last = 0;
m_lastFetched = DTM.NULL;
if (m_iterators != null)
{
int n = m_iterators.length;
for (int i = 0; i < n; i++)
{
m_iterators[i].reset();
m_iterators[i].nextNode();
}
}
}
/**
* 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.getOpMap()[opPos];
if (steptype == OpCodes.OP_LOCATIONPATH)
{
loadLocationPaths(compiler, compiler.getNextOpPos(opPos), count + 1);
m_iterators[count] = createDTMIterator(compiler, opPos);
}
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());
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_iterators[count] = iter;
break;
default :
m_iterators = new LocPathIterator[count];
}
}
}
/**
* 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 DTMIterator createDTMIterator(
Compiler compiler, int opPos) throws javax.xml.transform.TransformerException
{
DTMIterator lpi = WalkerFactory.newDTMIterator(compiler, opPos,
(compiler.getLocationPathDepth() <= 0));
return lpi;
}
/** The last node that was fetched, usually by nextNode. */
transient int m_lastFetched = DTM.NULL;
/**
* 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 the cache is on, and the node has already been found, then
// // just return from the list.
// if ((null != m_cachedNodes)
// && (m_cachedNodes.getCurrentPos() < m_cachedNodes.size()))
// {
// return m_cachedNodes.nextNode();
// }
// If the cache is on, and the node has already been found, then
// just return from the list.
if ((null != m_cachedNodes)
&& (m_next < m_cachedNodes.size()))
{
int next = m_cachedNodes.elementAt(m_next);
m_next++;
m_currentContextNode = next;
return next;
}
if (m_foundLast)
{
m_lastFetched = DTM.NULL;
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();
if (null != m_cachedNodes)
m_cachedNodes.addElement(earliestNode);
m_next++;
}
else
m_foundLast = true;
}
m_lastFetched = earliestNode;
return earliestNode;
}
/**
* If an index is requested, NodeSetDTM will call this method
* to run the iterator to the index. By default this sets
* m_next to the index. If the index argument is -1, this
* signals that the iterator should be run to the end.
*
* @param index The index to run to, or -1 if the iterator
* should run to the end.
*/
public void runTo(int index)
{
if (m_foundLast || ((index >= 0) && (index <= getCurrentPos())))
return;
int n;
if (-1 == index)
{
while (DTM.NULL != (n = nextNode()));
}
else
{
while (DTM.NULL != (n = nextNode()))
{
if (getCurrentPos() >= index)
break;
}
}
}
/**
* Get the current position, which is one less than
* the next nextNode() call will retrieve. i.e. if
* you call getCurrentPos() and the return is 0, the next
* fetch will take place at index 1.
*
* @return A value greater than or equal to zero that indicates the next
* node position to fetch.
*/
public int getCurrentPos()
{
return m_next;
}
/**
* The number of nodes in the list. The range of valid child node indices
* is 0 to <code>length-1</code> inclusive.
*
* @return The number of nodes in the list, always greater or equal to zero.
*/
public int getLength()
{
// resetToCachedList();
if(m_last > 0)
return m_last;
else if(null == m_cachedNodes || !m_foundLast)
{
m_last = getLastPos(m_execContext);
}
else
{
m_last = m_cachedNodes.getLength();
}
return m_last;
}
/**
* Get the index of the last node that can be itterated to.
* This probably will need to be overridded by derived classes.
*
* @param xctxt XPath runtime context.
*
* @return the index of the last node that can be itterated to.
*/
public int getLastPos(XPathContext xctxt)
{
int pos = m_next;
UnionPathIterator clone;
int savedPos;
if(null != m_cachedNodes)
savedPos = m_cachedNodes.getCurrentPos();
else
savedPos = -1;
try
{
// %REVIEW% %OPT%
if(0 == pos && m_currentContextNode != DTM.NULL)
clone = (UnionPathIterator) cloneWithReset();
else
clone = (UnionPathIterator) clone();
}
catch (CloneNotSupportedException cnse)
{
return -1;
}
int next;
pos = clone.getCurrentPos();
while (DTM.NULL != (next = clone.nextNode()))
{
pos++;
}
if(-1 != savedPos)
m_cachedNodes.setCurrentPos(savedPos);
return pos;
}
/**
* Returns the <code>index</code> th item in the collection. If
* <code>index</code> is greater than or equal to the number of nodes in
* the list, this returns <code>null</code> .
* @param index Index into the collection.
* @return The node at the <code>index</code> th position in the
* <code>NodeList</code> , or <code>null</code> if that is not a valid
* index.
*/
public int item(int index)
{
// resetToCachedList(); %TBD% ??
return m_cachedNodes.item(index);
}
/**
* Sets the node at the specified index of this vector to be the
* specified node. The previous component at that position is discarded.
*
* <p>The index must be a value greater than or equal to 0 and less
* than the current size of the vector.
* The iterator must be in cached mode.</p>
*
* <p>Meant to be used for sorted iterators.</p>
*
* @param node Node to set
* @param index Index of where to set the node
*/
public void setItem(int node, int index)
{
m_cachedNodes.setElementAt(node, index);
}
/**
* Set the current context node for this iterator.
*
* @param n Must be a non-null reference to the node context.
*/
public final void setRoot(int n)
{
m_context = n;
}
/**
* Set the environment in which this iterator operates, which should provide:
* a node (the context node... same value as "root" defined below)
* a pair of non-zero positive integers (the context position and the context size)
* a set of variable bindings
* a function library
* the set of namespace declarations in scope for the expression.
*
* <p>At this time the exact implementation of this environment is application
* dependent. Probably a proper interface will be created fairly soon.</p>
*
* @param environment The environment object.
*/
public void setEnvironment(Object environment)
{
// no-op for now.
}
/**
* Get an instance of the DTMManager. Since a node
* iterator may be passed without a DTMManager, this allows the
* caller to easily get the DTMManager using just the iterator.
*
* @return a non-null DTMManager reference.
*/
public DTMManager getDTMManager()
{
return m_execContext.getDTMManager();
}
/**
* Return the last fetched node.
*
* @return The last fetched node, or null if the last fetch was null.
*/
public int getCurrentNode()
{
return m_lastFetched;
}
/**
* 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_iterators.length; i++)
{
DTMIterator iter = m_iterators[i];
if(iter instanceof Expression)
{
((Expression)iter).fixupVariables(vars, globalsSize);
}
}
}
/**
* Tells if we've found the last node yet.
*/
transient protected boolean m_foundLast = false;
/**
* The execution context for the expression.
*/
transient protected XPathContext m_execContext;
/**
* The node context for the expression.
*/
transient protected int m_context = DTM.NULL;
/**
* The node context from where the Location Path is being
* executed from (i.e. for current() support).
*/
transient protected int m_currentContextNode = DTM.NULL;
/**
* Get an instance of a DTM that "owns" a node handle. Since a node
* iterator may be passed without a DTMManager, this allows the
* caller to easily get the DTM using just the iterator.
*
* @param nodeHandle the nodeHandle.
*
* @return a non-null DTM reference.
*/
public DTM getDTM(int nodeHandle)
{
return m_execContext.getDTM(nodeHandle);
}
/**
* The node context from where the expression is being
* executed from (i.e. for current() support).
*
* @return The top-level node context of the entire expression.
*/
public int getCurrentContextNode()
{
return m_currentContextNode;
}
/**
* 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;
/**
* The last index in the list.
*/
transient private int m_last = 0;
/**
* Get the index of the last node in the itteration.
*/
public int getLast()
{
return m_last;
}
/**
* Set the index of the last node in the itteration.
*/
public void setLast(int last)
{
m_last = last;
}
/**
* Returns true if all the nodes in the iteration well be returned in document
* order.
*
* @return true as a default.
*/
public boolean isDocOrdered()
{
return true;
}
/**
* 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;
}
}