weblogic.apache.xpath.axes
Class AxesWalker

java.lang.Object
  |
  +--weblogic.apache.xpath.Expression
        |
        +--weblogic.apache.xpath.patterns.NodeTest
              |
              +--weblogic.apache.xpath.axes.PredicatedNodeTest
                    |
                    +--weblogic.apache.xpath.axes.AxesWalker

Direct Known Subclasses:

FilterExprWalker, KeyWalker, ReverseAxesWalker

public class AxesWalker

extends PredicatedNodeTest

implements java.lang.Cloneable

Serves as common interface for axes Walkers, and stores common state variables.

This class is based on an implementation from the Apache XML Project. In future releases the XML parser, XSLT processor, and associated classes will likely be updated to be based on a later version of the Apache implementations. Since Apache does not guarantee backwards compatibility between versions of their software, we cannot guarantee backwards compatibility of any of the classes contained in the weblogic.apache package or sub-packages.

See Also:

Serialized Form

Field Summary

protected int	m_axis The traversal axis from where the nodes will be filtered.
protected AxesWalker	m_nextWalker The next walker in the location step chain.
protected weblogic.apache.xml.dtm.DTMAxisTraverser	m_traverser The DTM inner traversal class, that corresponds to the super axis.

Fields inherited from class weblogic.apache.xpath.axes.PredicatedNodeTest

m_foundLast, m_lpi, m_predCount, m_proximityPositions

Fields inherited from class weblogic.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 weblogic.apache.xpath.Expression

m_slocator

Constructor Summary

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

Method Summary

java.lang.Object	clone() Get a cloned AxesWalker.
int	getAxis() Returns the axis being iterated, if it is known.
int	getCurrentNode() The node at which the TreeWalker is currently positioned.
weblogic.apache.xml.dtm.DTM	getDTM(int node) Get the DTM for this walker.
int	getLastPos(XPathContext xctxt) Get the index of the last node that can be itterated to.
protected int	getNextNode() Get the next node in document order on the axes.
AxesWalker	getNextWalker() Get the next walker in the location step chain.
AxesWalker	getPrevWalker() Get the previous walker reference in the location step chain.
int	getRoot() The root node of the TreeWalker, as specified in setRoot(int root).
void	init(Compiler compiler, int opPos, int stepType) Initialize an AxesWalker during the parse of the XPath expression.
boolean	isDocOrdered() Returns true if all the nodes in the iteration well be returned in document order.
int	nextNode() Moves the TreeWalker to the next visible node in document order relative to the current node, and returns the new node.
void	setDefaultDTM(weblogic.apache.xml.dtm.DTM dtm) Set the DTM for this walker.
void	setNextWalker(AxesWalker walker) Set the next walker in the location step chain.
void	setPrevWalker(AxesWalker walker) Set or clear the previous walker reference in the location step chain.
void	setRoot(int root) Set the root node of the TreeWalker.
WalkingIterator	wi()

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

acceptNode, canTraverseOutsideSubtree, countProximityPosition, fixupVariables, getLocPathIterator, getPredicateCount, getPredicateIndex, getProximityPosition, getProximityPosition, getProximityPosition, initPredicateInfo, initProximityPosition, isReverseAxes, nodeToString, resetProximityPositions, setLocPathIterator, setPredicateCount

Methods inherited from class weblogic.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 weblogic.apache.xpath.Expression

asIterator, asNode, assertion, bool, error, executeCharsToContentHandler, isNodesetExpr, isStableNumber, num, setSourceLocator, warn, xstr

Methods inherited from class java.lang.Object

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

Field Detail

m_nextWalker

protected AxesWalker m_nextWalker

The next walker in the location step chain.

m_axis

protected int m_axis

The traversal axis from where the nodes will be filtered.

m_traverser

protected weblogic.apache.xml.dtm.DTMAxisTraverser m_traverser

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

Constructor Detail

AxesWalker

public AxesWalker(LocPathIterator locPathIterator,
                  int axis)

Construct an AxesWalker using a LocPathIterator.

Parameters:

locPathIterator - non-null reference to the parent iterator.

Method Detail

wi

public final WalkingIterator wi()

init

public void init(Compiler compiler,
                 int opPos,
                 int stepType)
          throws javax.xml.transform.TransformerException

Initialize an AxesWalker during the parse of the XPath expression.

Parameters:

compiler - The Compiler object that has information about this walker in the op map.

opPos - The op code position of this location step.

stepType - The type of location step.

Throws:

javax.xml.transform.TransformerException -

clone

public java.lang.Object clone()
                       throws java.lang.CloneNotSupportedException

Get a cloned AxesWalker.

Returns:

A new AxesWalker that can be used without mutating this one.

Throws:

java.lang.CloneNotSupportedException -

Overrides:

clone in class PredicatedNodeTest

getRoot

public int getRoot()

The root node of the TreeWalker, as specified in setRoot(int root). Note that this may actually be below the current node.

Returns:

The context node of the step.

setRoot

public void setRoot(int root)

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

Parameters:

root - The context node of this step.

getCurrentNode

public final int getCurrentNode()

The node at which the TreeWalker is currently positioned.
The value must not be null. Alterations to the DOM tree may cause the current node to no longer be accepted by the TreeWalker's associated filter. currentNode may also be explicitly set to any node, whether or not it is within the subtree specified by the root node or would be accepted by the filter and whatToShow flags. Further traversal occurs relative to currentNode even if it is not part of the current view by applying the filters in the requested direction (not changing currentNode where no traversal is possible).

Returns:

The node at which the TreeWalker is currently positioned, only null if setRoot has not yet been called.

setNextWalker

public void setNextWalker(AxesWalker walker)

Set the next walker in the location step chain.

Parameters:

walker - Reference to AxesWalker derivative, or may be null.

getNextWalker

public AxesWalker getNextWalker()

Get the next walker in the location step chain.

Returns:

Reference to AxesWalker derivative, or null.

setPrevWalker

public void setPrevWalker(AxesWalker walker)

Set or clear the previous walker reference in the location step chain.

Parameters:

walker - Reference to previous walker reference in the location step chain, or null.

getPrevWalker

public AxesWalker getPrevWalker()

Get the previous walker reference in the location step chain.

Returns:

Reference to previous walker reference in the location step chain, or null.

getNextNode

protected int getNextNode()

Get the next node in document order on the axes.

Returns:

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

nextNode

public int nextNode()

Moves the TreeWalker to the next visible node in document order relative to the current node, and returns the new node. If the current node has no next node, or if the search for nextNode attempts to step upward from the TreeWalker's root node, returns null , and retains the current node.

Returns:

The new node, or null if the current node has no next node in the TreeWalker's logical view.

getLastPos

public int getLastPos(XPathContext xctxt)

Get the index of the last node that can be itterated to.

Parameters:

xctxt - XPath runtime context.

Returns:

the index of the last node that can be itterated to.

Overrides:

getLastPos in class PredicatedNodeTest

setDefaultDTM

public void setDefaultDTM(weblogic.apache.xml.dtm.DTM dtm)

Set the DTM for this walker.

Parameters:

dtm - Non-null reference to a DTM.

getDTM

public weblogic.apache.xml.dtm.DTM getDTM(int node)

Get the DTM for this walker.

Returns:

Non-null reference to a DTM.

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!

Returns:

true as a default.

getAxis

public int getAxis()

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.