org.apache.xpath.axes
Class ReverseAxesWalker

java.lang.Object
  org.apache.xpath.Expression
      org.apache.xpath.patterns.NodeTest
          org.apache.xpath.axes.PredicatedNodeTest
              org.apache.xpath.axes.AxesWalker
                  org.apache.xpath.axes.ReverseAxesWalker

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, javax.xml.transform.SourceLocator, PathComponent, SubContextList, ExpressionNode, ExpressionOwner, XPathVisitable

public class ReverseAxesWalker
extends AxesWalker

Walker for a reverse axes.

See Also:

XPath 2.4 Predicates, Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.xpath.axes.PredicatedNodeTest

PredicatedNodeTest.PredOwner

Field Summary

protected DTMAxisIterator	m_iterator The DTM inner traversal class, that corresponds to the super axis.
(package private) static long	serialVersionUID

Fields inherited from class org.apache.xpath.axes.AxesWalker

m_axis, m_isFresh, m_nextWalker, m_prevWalker, m_root, m_traverser

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

Constructor Summary

ReverseAxesWalker(LocPathIterator locPathIterator, int axis)
Construct an AxesWalker using a LocPathIterator.

Method Summary

protected void	countProximityPosition(int i) Count backwards one proximity position.
void	detach() Detaches the walker from the set which it iterated over, releasing any computational resources and placing the iterator in the INVALID state.
int	getLastPos(XPathContext xctxt) Get the number of nodes in this node list.
protected int	getNextNode() Get the next node in document order on the axes.
protected int	getProximityPosition(int predicateIndex) Get the current sub-context position.
boolean	isDocOrdered() Returns true if all the nodes in the iteration well be returned in document order.
boolean	isReverseAxes() Tells if this is a reverse axes.
void	setRoot(int root) Set the root node of the TreeWalker.

Methods inherited from class org.apache.xpath.axes.AxesWalker

callVisitors, clone, cloneDeep, deepEquals, findClone, getAnalysisBits, getAxis, getCurrentNode, getDTM, getExpression, getNextWalker, getPrevWalker, getRoot, init, nextNode, setDefaultDTM, setExpression, setNextWalker, setPrevWalker, wi

Methods inherited from class org.apache.xpath.axes.PredicatedNodeTest

acceptNode, callPredicateVisitors, canTraverseOutsideSubtree, executePredicates, fixupVariables, getLocPathIterator, getPredicate, getPredicateCount, getPredicateIndex, getProximityPosition, getProximityPosition, initPredicateInfo, initProximityPosition, nodeToString, resetProximityPositions, setLocPathIterator, setPredicateCount

Methods inherited from class org.apache.xpath.patterns.NodeTest

calcScore, debugWhatToShow, execute, execute, execute, getDefaultScore, getLocalName, getNamespace, getNodeTypeTest, getStaticScore, getWhatToShow, initNodeTest, initNodeTest, setLocalName, setNamespace, setStaticScore, setWhatToShow

Methods inherited from class org.apache.xpath.Expression

asIterator, asIteratorRaw, asNode, assertion, bool, error, execute, executeCharsToContentHandler, exprAddChild, exprGetChild, exprGetNumChildren, exprGetParent, exprSetParent, getColumnNumber, getExpressionOwner, getLineNumber, getPublicId, getSystemId, isNodesetExpr, isSameClass, isStableNumber, num, warn, xstr

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

serialVersionUID

static final long serialVersionUID

See Also:

Constant Field Values

m_iterator

protected DTMAxisIterator m_iterator

The DTM inner traversal class, that corresponds to the super axis.

Constructor Detail

ReverseAxesWalker

ReverseAxesWalker(LocPathIterator locPathIterator,
                  int axis)

Construct an AxesWalker using a LocPathIterator.

Parameters:

locPathIterator - The location path iterator that 'owns' this walker.

Method Detail

setRoot

public void setRoot(int root)

Set the root node of the TreeWalker. (Not part of the DOM2 TreeWalker interface).

Overrides:

setRoot in class AxesWalker

Parameters:

root - The context node of this step.

detach

public void detach()

Detaches the walker from the set which it iterated over, releasing any computational resources and placing the iterator in the INVALID state.

Overrides:

detach in class AxesWalker

getNextNode

protected int getNextNode()

Get the next node in document order on the axes.

Overrides:

getNextNode in class AxesWalker

Returns:

the next node in document order on the axes, or null.

isReverseAxes

public boolean isReverseAxes()

Tells if this is a reverse axes. Overrides AxesWalker#isReverseAxes.

Overrides:

isReverseAxes in class PredicatedNodeTest

Returns:

true for this class.

getProximityPosition

protected int getProximityPosition(int predicateIndex)

Get the current sub-context position. In order to do the reverse axes count, for the moment this re-searches the axes up to the predicate. An optimization on this is to cache the nodes searched, but, for the moment, this case is probably rare enough that the added complexity isn't worth it.

Overrides:

getProximityPosition in class PredicatedNodeTest

Parameters:

predicateIndex - The predicate index of the proximity position.

Returns:

The pridicate index, or -1.

countProximityPosition

protected void countProximityPosition(int i)

Count backwards one proximity position.

Overrides:

countProximityPosition in class PredicatedNodeTest

Parameters:

i - The predicate index.

getLastPos

public int getLastPos(XPathContext xctxt)

Get the number of nodes in this node list. The function is probably ill named?

Specified by:

getLastPos in interface SubContextList

Overrides:

getLastPos in class AxesWalker

Parameters:

xctxt - The XPath runtime context.

Returns:

the number of nodes in this node list.

isDocOrdered

public boolean isDocOrdered()

Returns true if all the nodes in the iteration well be returned in document order. Warning: This can only be called after setRoot has been called!

Overrides:

isDocOrdered in class AxesWalker

Returns:

false.