http://xml.apache.org/xalan-j/: Serializer to write out XML, HTML etc. as a stream of characters from an input DOM or from input SAX events. (The Apache Software Foundation) 
/*
 * 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: LocPathIterator.java 468655 2006-10-28 07:12:06Z minchau $
 */
package org.apache.xpath.axes;

import org.apache.xalan.res.XSLMessages;
import org.apache.xml.dtm.DTM;
import org.apache.xml.dtm.DTMFilter;
import org.apache.xml.dtm.DTMIterator;
import org.apache.xml.dtm.DTMManager;
import org.apache.xml.utils.PrefixResolver;
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.objects.XNodeSet;
import org.apache.xpath.objects.XObject;
import org.apache.xpath.res.XPATHErrorResources;


This class extends NodeSetDTM, which implements NodeIterator,
and fetches nodes one at a time in document order based on a XPath


@xsl.usageadvanced
/**
 * This class extends NodeSetDTM, which implements NodeIterator,
 * and fetches nodes one at a time in document order based on a XPath
 * <a href="http://www.w3.org/TR/xpath#NT-LocationPath>LocationPath</a>.
 *
 * <p>If setShouldCacheNodes(true) is called,
 * as each node is iterated via nextNode(), the node is also stored
 * in the NodeVector, so that previousNode() can easily be done, except in
 * the case where the LocPathIterator is "owned" by a UnionPathIterator,
 * in which case the UnionPathIterator will cache the nodes.</p>
 * @xsl.usage advanced
 */
public abstract class LocPathIterator extends PredicatedNodeTest
        implements Cloneable, DTMIterator, java.io.Serializable, PathComponent
{
    static final long serialVersionUID = -4602476357268405754L;
	
  
Create a LocPathIterator object.

/**
   * Create a LocPathIterator object.
   *
   */
  protected LocPathIterator()
  {
  }


  
Create a LocPathIterator object.

Params:
  • nscontext – The namespace context for this iterator,
should be OK if null.
/**
   * Create a LocPathIterator object.
   *
   * @param nscontext The namespace context for this iterator,
   * should be OK if null.
   */
  protected LocPathIterator(PrefixResolver nscontext)
  {

    setLocPathIterator(this);
    m_prefixResolver = nscontext;
  }

  
Create a LocPathIterator object, including creation
of step walkers from the opcode list, and call back
into the Compiler to create predicate expressions.

Params:
  • compiler – The Compiler which is creating
this expression.
  • opPos – The position of this iterator in the
opcode list from the compiler.
Throws:
/**
   * Create a LocPathIterator object, including creation
   * of step walkers 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
   */
  protected LocPathIterator(Compiler compiler, int opPos, int analysis)
          throws javax.xml.transform.TransformerException
  {
    this(compiler, opPos, analysis, true);
  }

  
Create a LocPathIterator object, including creation
of step walkers from the opcode list, and call back
into the Compiler to create predicate expressions.

Params:
  • compiler – The Compiler which is creating
this expression.
  • opPos – The position of this iterator in the
opcode list from the compiler.
  • shouldLoadWalkers – True if walkers should be
loaded, or false if this is a derived iterator and
it doesn't wish to load child walkers.
Throws:
/**
   * Create a LocPathIterator object, including creation
   * of step walkers 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.
   * @param shouldLoadWalkers True if walkers should be
   * loaded, or false if this is a derived iterator and
   * it doesn't wish to load child walkers.
   *
   * @throws javax.xml.transform.TransformerException
   */
  protected LocPathIterator(
          Compiler compiler, int opPos, int analysis, boolean shouldLoadWalkers)
            throws javax.xml.transform.TransformerException
  {
    setLocPathIterator(this);
  }
  
  
Get the analysis bits for this walker, as defined in the WalkerFactory.

Returns:One of WalkerFactory#BIT_DESCENDANT, etc.
/** 
   * Get the analysis bits for this walker, as defined in the WalkerFactory.
   * @return One of WalkerFactory#BIT_DESCENDANT, etc.
   */
  public int getAnalysisBits()
  {
  	int axis = getAxis();
  	int bit = WalkerFactory.getAnalysisBitFromAxes(axis);
  	return bit;
  }
  
  
Read the object from a serialization stream.

Params:
  • stream – Input stream to read from
Throws:
/**
   * 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);
    }
  }
  
  
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.

At this time the exact implementation of this environment is application 
dependent.  Probably a proper interface will be created fairly soon.


Params:
  • environment – The environment object.
/**
   * 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 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.

Params:
  • nodeHandle – the nodeHandle.
Returns:a non-null DTM reference.
/**
   * 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)
  {
    // %OPT%
    return m_execContext.getDTM(nodeHandle);
  }
  
  
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.

Returns:a non-null DTMManager reference.
/**
   * 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();
  }
  
  
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.

Params:
  • xctxt – The XPath execution context.
Throws:
Returns:An XNodeSet reference that holds this iterator.
/**
   * 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
  {

    XNodeSet iter = new XNodeSet((LocPathIterator)m_clones.getInstance());

    iter.setRoot(xctxt.getCurrentNode(), xctxt);

    return iter;
  }
    
  
Execute an expression in the XPath runtime context, and return the
result of the expression.

Params:
  • xctxt – The XPath runtime context.
  • handler – The target content handler.
Throws:
Returns:The result of the expression in the form of a XObject.
/**
   * Execute an expression in the XPath runtime context, and return the
   * result of the expression.
   *
   *
   * @param xctxt The XPath runtime context.
   * @param handler The target content handler.
   *
   * @return The result of the expression in the form of a <code>XObject</code>.
   *
   * @throws javax.xml.transform.TransformerException if a runtime exception
   *         occurs.
   * @throws org.xml.sax.SAXException
   */
  public void executeCharsToContentHandler(
          XPathContext xctxt, org.xml.sax.ContentHandler handler)
            throws javax.xml.transform.TransformerException,
                   org.xml.sax.SAXException
  {
    LocPathIterator clone = (LocPathIterator)m_clones.getInstance();

    int current = xctxt.getCurrentNode();
    clone.setRoot(current, xctxt);
    
    int node = clone.nextNode();
    DTM dtm = clone.getDTM(node);
    clone.detach();
	
    if(node != DTM.NULL)
    {
      dtm.dispatchCharactersEvents(node, handler, false);
    }
  }
  
  
Given an select expression and a context, evaluate the XPath
and return the resulting iterator.

Params:
  • xctxt – The execution context.
  • contextNode – The node that "." expresses.
Throws:
  • TransformerException – thrown if the active ProblemListener decides
the error condition is severe enough to halt processing.
  • TransformerException – 
@xsl.usageexperimental
/**
   * 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.
   * @throws TransformerException thrown if the active ProblemListener decides
   * the error condition is severe enough to halt processing.
   *
   * @throws javax.xml.transform.TransformerException
   * @xsl.usage experimental
   */
  public DTMIterator asIterator(
          XPathContext xctxt, int contextNode)
            throws javax.xml.transform.TransformerException
  {
    XNodeSet iter = new XNodeSet((LocPathIterator)m_clones.getInstance());

    iter.setRoot(contextNode, xctxt);

    return iter;
  }

  
  
Tell if the expression is a nodeset expression.

Returns:true if the expression can be represented as a nodeset.
/**
   * Tell if the expression is a nodeset expression.
   * 
   * @return true if the expression can be represented as a nodeset.
   */
  public boolean isNodesetExpr()
  {
    return true;
  }
  
  
Return the first node out of the nodeset, if this expression is 
a nodeset expression.  This is the default implementation for 
nodesets.  Derived classes should try and override this and return a 
value without having to do a clone operation.

Params:
  • xctxt – The XPath runtime context.
Returns:the first node out of the nodeset, or DTM.NULL.
/**
   * Return the first node out of the nodeset, if this expression is 
   * a nodeset expression.  This is the default implementation for 
   * nodesets.  Derived classes should try and override this and return a 
   * value without having to do a clone operation.
   * @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
  {
    DTMIterator iter = (DTMIterator)m_clones.getInstance();
    
    int current = xctxt.getCurrentNode();
    
    iter.setRoot(current, xctxt);

    int next = iter.nextNode();
    // m_clones.freeInstance(iter);
    iter.detach();
    return next;
  }
  
  
Evaluate this operation directly to a boolean.

Params:
  • xctxt – The runtime execution context.
Throws:
Returns:The result of the operation as a boolean.
/**
   * Evaluate this operation directly to a boolean.
   *
   * @param xctxt The runtime execution context.
   *
   * @return The result of the operation as a boolean.
   *
   * @throws javax.xml.transform.TransformerException
   */
  public boolean bool(XPathContext xctxt)
          throws javax.xml.transform.TransformerException
  {
    return (asNode(xctxt) != DTM.NULL);
  }


  
Set if this is an iterator at the upper level of
the XPath.

Params:
  • b – true if this location path is at the top level of the
         expression.
@xsl.usageadvanced
/**
   * Set if this is an iterator at the upper level of
   * the XPath.
   *
   * @param b true if this location path is at the top level of the
   *          expression.
   * @xsl.usage advanced
   */
  public void setIsTopLevel(boolean b)
  {
    m_isTopLevel = b;
  }

  
Get if this is an iterator at the upper level of
the XPath.

Returns:true if this location path is at the top level of the
         expression.
@xsl.usageadvanced
/**
   * Get if this is an iterator at the upper level of
   * the XPath.
   *
   * @return true if this location path is at the top level of the
   *          expression.
   * @xsl.usage advanced
   */
  public boolean getIsTopLevel()
  {
    return m_isTopLevel;
  }
  
  
Initialize the context values for this expression
after it is cloned.

Params:
  • context – The XPath runtime context for this
transformation.
/**
   * 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)
  {

    m_context = context;
    
    XPathContext xctxt = (XPathContext)environment;
    m_execContext = xctxt;
    m_cdtm = xctxt.getDTM(context);
    
    m_currentContextNode = context; // only if top level?
    
    // Yech, shouldn't have to do this.  -sb
    if(null == m_prefixResolver)
    	m_prefixResolver = xctxt.getNamespaceContext();
        
    m_lastFetched = DTM.NULL;
    m_foundLast = false;
    m_pos = 0;
    m_length = -1;

    if (m_isTopLevel)
      this.m_stackFrame = xctxt.getVarStack().getStackFrame();
      
    // reset();
  }

  
Set the next position index of this iterator.

Params:
  • next – A value greater than or equal to zero that indicates the next
node position to fetch.
/**
   * Set the next position index of this iterator.
   *
   * @param next A value greater than or equal to zero that indicates the next
   * node position to fetch.
   */
  protected void setNextPosition(int next)
  {
    assertion(false, "setNextPosition not supported in this iterator!");
  }

  
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.

Returns:A value greater than or equal to zero that indicates the next
node position to fetch.
/**
   * 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 final int getCurrentPos()
  {
    return m_pos;
  }


  
If setShouldCacheNodes(true) is called, then nodes will
be cached.  They are not cached by default.

Params:
  • b – True if this iterator should cache nodes.
/**
   * 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)
  {

    assertion(false, "setShouldCacheNodes not supported by this iterater!");
  }
  
  
Tells if this iterator can have nodes added to it or set via 
the setItem(int node, int index) method.

Returns:True if the nodelist can be mutated.
/**
   * 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 false;
  }

  
Set the current position in the node set.

Params:
  • i – Must be a valid index greater
than or equal to zero and less than m_cachedNodes.size().
/**
   * Set the current position in the node set.
   *
   * @param i Must be a valid index greater
   * than or equal to zero and less than m_cachedNodes.size().
   */
  public void setCurrentPos(int i)
  {
  	assertion(false, "setCurrentPos not supported by this iterator!");
  }
  
  
Increment the current position in the node set.

/**
   * Increment the current position in the node set.
   */
  public void incrementCurrentPos()
  {
  	m_pos++;
  }


  
Get the length of the cached nodes.

Note: for the moment at least, this only returns
the size of the nodes that have been fetched to date,
it doesn't attempt to run to the end to make sure we
have found everything.  This should be reviewed.


Returns:The size of the current cache list.
/**
   * Get the length of the cached nodes.
   *
   * <p>Note: for the moment at least, this only returns
   * the size of the nodes that have been fetched to date,
   * it doesn't attempt to run to the end to make sure we
   * have found everything.  This should be reviewed.</p>
   *
   * @return The size of the current cache list.
   */
  public int size()
  {
	assertion(false, "size() not supported by this iterator!");
	return 0;
  }

  
 Returns the index th item in the collection. If
index is greater than or equal to the number of nodes in
the list, this returns null .

Params:
  • index –  Index into the collection.
Returns: The node at the index th position in the
  NodeList , or null if that is not a valid
  index.
/**
   *  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)
  {
	assertion(false, "item(int index) not supported by this iterator!");
	return 0;
  }
  
  
Sets the node at the specified index of this vector to be the
specified node. The previous component at that position is discarded.

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.


Meant to be used for sorted iterators.


Params:
  • node – Node to set
  • index – Index of where to set the node
/**
   * 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)
  {
	assertion(false, "setItem not supported by this iterator!");
  }

  
 The number of nodes in the list. The range of valid child node indices
is 0 to length-1 inclusive.

Returns:The number of nodes in the list, always greater or equal to zero.
/**
   *  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()
  {      
    // Tell if this is being called from within a predicate.
  	boolean isPredicateTest = (this == m_execContext.getSubContextList());

    // And get how many total predicates are part of this step.
  	int predCount = getPredicateCount();
  	
    // If we have already calculated the length, and the current predicate 
    // is the first predicate, then return the length.  We don't cache 
    // the anything but the length of the list to the first predicate.
    if (-1 != m_length && isPredicateTest && m_predicateIndex < 1)
  		return m_length;
  	
    // I'm a bit worried about this one, since it doesn't have the 
    // checks found above.  I suspect it's fine.  -sb
    if (m_foundLast)
  		return m_pos;
  		
    // Create a clone, and count from the current position to the end 
    // of the list, not taking into account the current predicate and 
    // predicates after the current one.
    int pos = (m_predicateIndex >= 0) ? getProximityPosition() : m_pos;
              
    LocPathIterator clone;

    try
    {
      clone = (LocPathIterator) clone();        
    }
    catch (CloneNotSupportedException cnse)
    {
      return -1;
    }

    // We want to clip off the last predicate, but only if we are a sub 
    // context node list, NOT if we are a context list.  See pos68 test, 
    // also test against bug4638.
    if (predCount > 0 && isPredicateTest)
    {
      // Don't call setPredicateCount, because it clones and is slower.
      clone.m_predCount = m_predicateIndex;
      // The line above used to be:
      // clone.m_predCount = predCount - 1;
      // ...which looks like a dumb bug to me. -sb
    }

    int next;

    while (DTM.NULL != (next = clone.nextNode()))
    {
      pos++;
    }
    
    if (isPredicateTest && m_predicateIndex < 1)
      m_length = pos;
    
    return pos;
  }

  
Tells if this NodeSetDTM is "fresh", in other words, if
the first nextNode() that is called will return the
first node in the set.

Returns:true of nextNode has not been called.
/**
   * 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 of nextNode has not been called.
   */
  public boolean isFresh()
  {
    return (m_pos == 0);
  }

  
 Returns the previous node in the set and moves the position of the
iterator backwards in the set.

Returns: The previous Node in the set being iterated over,
  ornull if there are no more members in that set.
/**
   *  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()
  {
    throw new RuntimeException(
      XSLMessages.createXPATHMessage(XPATHErrorResources.ER_NODESETDTM_CANNOT_ITERATE, null)); //"This NodeSetDTM can not iterate to a previous node!");
  }

  
This attribute determines which node types are presented via the
iterator. The available set of constants is defined in the
NodeFilter interface.

This is somewhat useless at this time, since it doesn't
really return information that tells what this iterator will
show.  It is here only to fullfill the DOM NodeIterator
interface.


See Also:
Returns:For now, always NodeFilter.SHOW_ALL & ~NodeFilter.SHOW_ENTITY_REFERENCE.
/**
   * This attribute determines which node types are presented via the
   * iterator. The available set of constants is defined in the
   * <code>NodeFilter</code> interface.
   *
   * <p>This is somewhat useless at this time, since it doesn't
   * really return information that tells what this iterator will
   * show.  It is here only to fullfill the DOM NodeIterator
   * interface.</p>
   *
   * @return For now, always NodeFilter.SHOW_ALL & ~NodeFilter.SHOW_ENTITY_REFERENCE.
   * @see org.w3c.dom.traversal.NodeIterator
   */
  public int getWhatToShow()
  {

    // TODO: ??
    return DTMFilter.SHOW_ALL & ~DTMFilter.SHOW_ENTITY_REFERENCE;
  }

  
 The filter used to screen nodes.  Not used at this time,
this is here only to fullfill the DOM NodeIterator
interface.

See Also:
Returns:Always null.
/**
   *  The filter used to screen nodes.  Not used at this time,
   * this is here only to fullfill the DOM NodeIterator
   * interface.
   *
   * @return Always null.
   * @see org.w3c.dom.traversal.NodeIterator
   */
  public DTMFilter getFilter()
  {
    return null;
  }

  
The root node of the Iterator, as specified when it was created.

Returns:The "root" of this iterator, which, in XPath terms,
is the node context for this iterator.
/**
   * The root node of the Iterator, as specified when it was created.
   *
   * @return The "root" of this iterator, which, in XPath terms,
   * is the node context for 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.

 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.

Returns:Always true, since entity reference nodes are not
visible in the XPath model.
/**
   *  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 Always true, since entity reference nodes are not
   * visible in the XPath model.
   */
  public boolean getExpandEntityReferences()
  {
    return true;
  }
  
  
Control over whether it is OK for detach to reset the iterator. 
/** Control over whether it is OK for detach to reset the iterator. */
  protected boolean m_allowDetach = true;
  
  
Specify if it's OK for detach to release the iterator for reuse.

Params:
  • allowRelease – true if it is OK for detach to release this iterator 
for pooling.
/**
   * 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. Afterdetach has been invoked, calls to
nextNode orpreviousNode will raise the
exception INVALID_STATE_ERR.

/**
   *  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)
    {
      // sb: allow reusing of cached nodes when possible?
      // m_cachedNodes = null;
      m_execContext = null;
      // m_prefixResolver = null;  sb: Why would this ever want to be null?
      m_cdtm = null;
      m_length = -1;
      m_pos = 0;
      m_lastFetched = DTM.NULL;
      m_context = DTM.NULL;
      m_currentContextNode = DTM.NULL;
      
      m_clones.freeInstance(this);
    }
  }
  
  
Reset the iterator.

/**
   * Reset the iterator.
   */
  public void reset()
  {
  	assertion(false, "This iterator can not reset!");
  }

  
Get a cloned Iterator that is reset to the beginning
of the query.

Throws:
Returns:A cloned NodeIterator set of the start of the query.
/**
   * 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
  {
    LocPathIterator clone;
//    clone = (LocPathIterator) clone();
    clone = (LocPathIterator)m_clones.getInstanceOrThrow();
    clone.m_execContext = m_execContext;
    clone.m_cdtm = m_cdtm;
    
    clone.m_context = m_context;
    clone.m_currentContextNode = m_currentContextNode;
    clone.m_stackFrame = m_stackFrame;

    // 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
//  {
//
//    LocPathIterator clone = (LocPathIterator) super.clone();
//
//    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.

Returns: The next Node in the set being iterated over, or
  null if there are no more members in that set.
/**
   *  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.
   */
  public abstract int nextNode();

  
Bottleneck the return of a next node, to make returns
easier from nextNode().

Params:
  • nextNode – The next node found, may be null.
Returns:The same node that was passed as an argument.
/**
   * Bottleneck the return of a next node, to make returns
   * easier from nextNode().
   *
   * @param nextNode The next node found, may be null.
   *
   * @return The same node that was passed as an argument.
   */
  protected int returnNextNode(int nextNode)
  {

    if (DTM.NULL != nextNode)
    {
      m_pos++;
    }

    m_lastFetched = nextNode;

    if (DTM.NULL == nextNode)
      m_foundLast = true;

    return nextNode;
  }

  
Return the last fetched node.  Needed to support the UnionPathIterator.

Returns:The last fetched node, or null if the last fetch was null.
/**
   * Return the last fetched node.  Needed to support the UnionPathIterator.
   *
   * @return The last fetched node, or null if the last fetch was null.
   */
  public int getCurrentNode()
  {
    return m_lastFetched;
  }

  
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.

Params:
  • index – The index to run to, or -1 if the iterator
should run to the end.
/**
   * 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;
      }
    }
  }

  
Tells if we've found the last node yet.

Returns:true if the last nextNode returned null.
/**
   * Tells if we've found the last node yet.
   *
   * @return true if the last nextNode returned null.
   */
  public final boolean getFoundLast()
  {
    return m_foundLast;
  }

  
The XPath execution context we are operating on.

Returns:XPath execution context this iterator is operating on,
or null if setRoot has not been called.
/**
   * The XPath execution context we are operating on.
   *
   * @return XPath execution context this iterator is operating on,
   * or null if setRoot has not been called.
   */
  public final XPathContext getXPathContext()
  {
    return m_execContext;
  }

  
The node context for the iterator.

Returns:The node context, same as getRoot().
/**
   * The node context for the iterator.
   *
   * @return The node context, same as getRoot().
   */
  public final int getContext()
  {
    return m_context;
  }

  
The node context from where the expression is being
executed from (i.e. for current() support).

Returns:The top-level node context of the entire expression.
/**
   * 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 final int getCurrentContextNode()
  {
    return m_currentContextNode;
  }

  
Set the current context node for this iterator.

Params:
  • n – Must be a non-null reference to the node context.
/**
   * Set the current context node for this iterator.
   *
   * @param n Must be a non-null reference to the node context.
   */
  public final void setCurrentContextNode(int n)
  {
    m_currentContextNode = n;
  }
  
//  /**
//   * Set the current context node for this iterator.
//   *
//   * @param n Must be a non-null reference to the node context.
//   */
//  public void setRoot(int n)
//  {
//    m_context = n;
//    m_cdtm = m_execContext.getDTM(n);
//  }

  
Return the saved reference to the prefix resolver that
was in effect when this iterator was created.

Returns:The prefix resolver or this iterator, which may be null.
/**
   * Return the saved reference to the prefix resolver that
   * was in effect when this iterator was created.
   *
   * @return The prefix resolver or this iterator, which may be null.
   */
  public final PrefixResolver getPrefixResolver()
  {
  	if(null == m_prefixResolver)
  	{
    	m_prefixResolver = (PrefixResolver)getExpressionOwner();
  	}

    return m_prefixResolver;
  }
        
//  /**
//   * Get the analysis pattern built by the WalkerFactory.
//   *
//   * @return The analysis pattern built by the WalkerFactory.
//   */
//  int getAnalysis()
//  {
//    return m_analysis;
//  }

//  /**
//   * Set the analysis pattern built by the WalkerFactory.
//   *
//   * @param a The analysis pattern built by the WalkerFactory.
//   */
//  void setAnalysis(int a)
//  {
//    m_analysis = a;
//  }

  
See Also:
  • callVisitors.callVisitors(ExpressionOwner, XPathVisitor)
/**
   * @see org.apache.xpath.XPathVisitable#callVisitors(ExpressionOwner, XPathVisitor)
   */
  public void callVisitors(ExpressionOwner owner, XPathVisitor visitor)
  {
  	 	if(visitor.visitLocationPath(owner, this))
  	 	{
  	 		visitor.visitStep(owner, this);
  	 		callPredicateVisitors(visitor);
  	 	}
  }  

  
  //============= State Data =============
  
  
The pool for cloned iterators.  Iterators need to be cloned
because the hold running state, and thus the original iterator
expression from the stylesheet pool can not be used.          

/** 
   * The pool for cloned iterators.  Iterators need to be cloned
   * because the hold running state, and thus the original iterator
   * expression from the stylesheet pool can not be used.          
   */
  transient protected IteratorPool m_clones = new IteratorPool(this);
  
  
The dtm of the context node.  Careful about using this... it may not 
be the dtm of the current node.

/** 
   * The dtm of the context node.  Careful about using this... it may not 
   * be the dtm of the current node.
   */
  transient protected DTM m_cdtm;
  
  
The stack frame index for this iterator.

/**
   * The stack frame index for this iterator.
   */
  transient int m_stackFrame = -1;

  
Value determined at compile time, indicates that this is an
iterator at the top level of the expression, rather than inside
a predicate.

@serial
/**
   * Value determined at compile time, indicates that this is an
   * iterator at the top level of the expression, rather than inside
   * a predicate.
   * @serial

   */
  private boolean m_isTopLevel = false;

  
The last node that was fetched, usually by nextNode. 
/** The last node that was fetched, usually by nextNode. */
  transient public int m_lastFetched = DTM.NULL;

  
The context node for this iterator, which doesn't change through
the course of the iteration.

/**
   * The context node for this iterator, which doesn't change through
   * the course of the iteration.
   */
  transient protected int m_context = DTM.NULL;

  
The node context from where the expression is being
executed from (i.e. for current() support).  Different
from m_context in that this is the context for the entire
expression, rather than the context for the subexpression.

/**
   * The node context from where the expression is being
   * executed from (i.e. for current() support).  Different
   * from m_context in that this is the context for the entire
   * expression, rather than the context for the subexpression.
   */
  transient protected int m_currentContextNode = DTM.NULL;
  
  
The current position of the context node.

/**
   * The current position of the context node.
   */
  transient protected int m_pos = 0;
  
  transient protected int m_length = -1;

  
Fast access to the current prefix resolver.  It isn't really
clear that this is needed.

@serial
/**
   * Fast access to the current prefix resolver.  It isn't really
   * clear that this is needed.
   * @serial

   */
  private PrefixResolver m_prefixResolver;

  
The XPathContext reference, needed for execution of many
operations.

/**
   * The XPathContext reference, needed for execution of many
   * operations.
   */
  transient protected XPathContext m_execContext;
  
  
Returns true if all the nodes in the iteration well be returned in document 
order.

Returns:true as a default.
/**
   * 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.

Returns:Axis.CHILD, etc., or -1 if the axis is not known or is of multiple 
types.
/**
   * 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 -1;
  }


//  /**
//   * The analysis pattern built by the WalkerFactory.
//   * TODO: Move to LocPathIterator.
//   * @see org.apache.xpath.axes.WalkerFactory
//   * @serial
//   */
//  protected int m_analysis = 0x00000000;
  
See Also:
  • getLastPos.getLastPos(XPathContext)
/**
   * @see PredicatedNodeTest#getLastPos(XPathContext)
   */
  public int getLastPos(XPathContext xctxt)
  {
    return getLength();
  }

}