org.apache.xpath.axes
Class DescendantIterator

java.lang.Object
  extended byorg.apache.xpath.Expression
      extended byorg.apache.xpath.patterns.NodeTest
          extended byorg.apache.xpath.axes.PredicatedNodeTest
              extended byorg.apache.xpath.axes.LocPathIterator
                  extended byorg.apache.xpath.axes.DescendantIterator
All Implemented Interfaces:
Cloneable, DTMIterator, ExpressionNode, PathComponent, Serializable, javax.xml.transform.SourceLocator, SubContextList, XPathVisitable

public class DescendantIterator
extends LocPathIterator

This class implements an optimized iterator for descendant, descendant-or-self, or "//foo" patterns.

See Also:
org.apache.xpath.axes.WalkerFactory#newLocPathIterator, Serialized Form

Nested Class Summary
 
Nested classes inherited from class org.apache.xpath.axes.PredicatedNodeTest
PredicatedNodeTest.PredOwner
 
Field Summary
protected  int m_axis
          The axis that we are traversing.
protected  int m_extendedTypeID
          The extended type ID, not set until setRoot.
protected  DTMAxisTraverser m_traverser
          The traverser to use to navigate over the descendants.
 
Fields inherited from class org.apache.xpath.axes.LocPathIterator
m_allowDetach, m_cdtm, m_clones, m_context, m_currentContextNode, m_execContext, m_lastFetched, m_length, m_pos, m_stackFrame
 
Fields inherited from class org.apache.xpath.axes.PredicatedNodeTest
DEBUG_PREDICATECOUNTING, m_foundLast, m_lpi, m_predCount, m_predicateIndex, m_proximityPositions
 
Fields inherited from class org.apache.xpath.patterns.NodeTest
m_name, m_whatToShow, SCORE_NODETEST, SCORE_NONE, SCORE_NSWILD, SCORE_OTHER, SCORE_QNAME, SHOW_BYFUNCTION, SUPPORTS_PRE_STRIPPING, WILD
 
Fields inherited from class org.apache.xpath.Expression
 
Fields inherited from interface org.apache.xml.dtm.DTMIterator
FILTER_ACCEPT, FILTER_REJECT, FILTER_SKIP
 
Constructor Summary
  DescendantIterator()
          Create a DescendantIterator object.
(package private) DescendantIterator(Compiler compiler, int opPos, int analysis)
          Create a DescendantIterator object.
 
Method Summary
 int asNode(XPathContext xctxt)
          Return the first node out of the nodeset, if this expression is a nodeset expression.
 DTMIterator cloneWithReset()
          Get a cloned Iterator that is reset to the beginning of the query.
 boolean deepEquals(Expression expr)
          Compare this object with another object and see if they are equal, include the sub heararchy.
 void detach()
          Detaches the iterator from the set which it iterated over, releasing any computational resources and placing the iterator in the INVALID state.
 int getAxis()
          Returns the axis being iterated, if it is known.
 int nextNode()
          Returns the next node in the set and advances the position of the iterator in the set.
 void setRoot(int context, Object environment)
          Initialize the context values for this expression after it is cloned.
 
Methods inherited from class org.apache.xpath.axes.LocPathIterator
allowDetachToRelease, asIterator, bool, callVisitors, execute, executeCharsToContentHandler, getAnalysisBits, getContext, getCurrentContextNode, getCurrentNode, getCurrentPos, getDTM, getDTMManager, getExpandEntityReferences, getFilter, getFoundLast, getIsTopLevel, getLastPos, getLength, getPrefixResolver, getRoot, getWhatToShow, getXPathContext, incrementCurrentPos, isDocOrdered, isFresh, isMutable, isNodesetExpr, item, previousNode, reset, returnNextNode, runTo, setCurrentContextNode, setCurrentPos, setEnvironment, setIsTopLevel, setItem, setNextPosition, setShouldCacheNodes, size
 
Methods inherited from class org.apache.xpath.axes.PredicatedNodeTest
acceptNode, callPredicateVisitors, canTraverseOutsideSubtree, clone, countProximityPosition, executePredicates, fixupVariables, getLocPathIterator, getPredicate, getPredicateCount, getPredicateIndex, getProximityPosition, getProximityPosition, getProximityPosition, initPredicateInfo, initProximityPosition, isReverseAxes, nodeToString, resetProximityPositions, setLocPathIterator, setPredicateCount
 
Methods inherited from class org.apache.xpath.patterns.NodeTest
calcScore, debugWhatToShow, execute, execute, getDefaultScore, getLocalName, getNamespace, getNodeTypeTest, getStaticScore, initNodeTest, initNodeTest, setLocalName, setNamespace, setStaticScore, setWhatToShow
 
Methods inherited from class org.apache.xpath.Expression
asIteratorRaw, assertion, error, execute, exprAddChild, exprGetChild, exprGetNumChildren, exprGetParent, exprSetParent, getColumnNumber, getExpressionOwner, getLineNumber, getPublicId, getSystemId, isSameClass, isStableNumber, num, warn, xstr
 
Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface org.apache.xml.dtm.DTMIterator
clone
 

Field Detail

m_traverser

protected transient DTMAxisTraverser m_traverser
The traverser to use to navigate over the descendants.


m_axis

protected int m_axis
The axis that we are traversing.


m_extendedTypeID

protected int m_extendedTypeID
The extended type ID, not set until setRoot.

Constructor Detail

DescendantIterator

DescendantIterator(Compiler compiler,
                   int opPos,
                   int analysis)
             throws javax.xml.transform.TransformerException
Create a DescendantIterator object.

Parameters:
compiler - A reference to the Compiler that contains the op map.
opPos - The position within the op map, which contains the location path expression for this itterator.
Throws:
javax.xml.transform.TransformerException

DescendantIterator

public DescendantIterator()
Create a DescendantIterator object.

Throws:
javax.xml.transform.TransformerException
Method Detail

cloneWithReset

public DTMIterator cloneWithReset()
                           throws CloneNotSupportedException
Get a cloned Iterator that is reset to the beginning of the query.

Specified by:
cloneWithReset in interface DTMIterator
Overrides:
cloneWithReset in class LocPathIterator
Returns:
A cloned NodeIterator set of the start of the query.
Throws:
CloneNotSupportedException

nextNode

public int nextNode()
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.

Specified by:
nextNode in interface DTMIterator
Specified by:
nextNode in class LocPathIterator
Returns:
The next Node in the set being iterated over, or null if there are no more members in that set.
Throws:
DOMException - INVALID_STATE_ERR: Raised if this method is called after the detach method was invoked.

setRoot

public void setRoot(int context,
                    Object environment)
Initialize the context values for this expression after it is cloned.

Specified by:
setRoot in interface DTMIterator
Overrides:
setRoot in class LocPathIterator

asNode

public int asNode(XPathContext xctxt)
           throws javax.xml.transform.TransformerException
Return the first node out of the nodeset, if this expression is a nodeset expression. This is the default implementation for nodesets.

WARNING: Do not mutate this class from this function!

Overrides:
asNode in class LocPathIterator
Parameters:
xctxt - The XPath runtime context.
Returns:
the first node out of the nodeset, or DTM.NULL.
Throws:
javax.xml.transform.TransformerException

detach

public void detach()
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.

Specified by:
detach in interface DTMIterator
Overrides:
detach in class LocPathIterator

getAxis

public int getAxis()
Returns the axis being iterated, if it is known.

Specified by:
getAxis in interface DTMIterator
Overrides:
getAxis in class LocPathIterator
Returns:
Axis.CHILD, etc., or -1 if the axis is not known or is of multiple types.

deepEquals

public boolean deepEquals(Expression expr)
Description copied from class: Expression
Compare this object with another object and see if they are equal, include the sub heararchy.

Overrides:
deepEquals in class PredicatedNodeTest
See Also:
Expression.deepEquals(Expression)