org.htmlunit.xpath.axes

Class AxesWalker

java.lang.Object

org.htmlunit.xpath.Expression

org.htmlunit.xpath.patterns.NodeTest

org.htmlunit.xpath.axes.PredicatedNodeTest

org.htmlunit.xpath.axes.AxesWalker

All Implemented Interfaces:

Cloneable, SourceLocator, PathComponent, SubContextList, ExpressionNode, XPathVisitable

Direct Known Subclasses:

FilterExprWalker, ReverseAxesWalker

public class AxesWalker
extends PredicatedNodeTest
implements Cloneable, PathComponent

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

Field Summary

Fields

Modifier and Type	Field and Description
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 DTMAxisTraverser	m_traverser The DTM inner traversal class, that corresponds to the super axis.

Fields inherited from class org.htmlunit.xpath.axes.PredicatedNodeTest

m_foundLast, m_lpi, m_predCount, m_proximityPositions

Fields inherited from class org.htmlunit.xpath.patterns.NodeTest

m_name, m_whatToShow, SCORE_NODETEST, SCORE_NONE, SCORE_NSWILD, SCORE_OTHER, SCORE_QNAME, SHOW_BYFUNCTION, WILD

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method and Description
void	callVisitors(XPathVisitor visitor) This will traverse the hierarchy, calling the visitor for each member.
Object	clone()
boolean	deepEquals(Expression expr) Compare this object with another object and see if they are equal, include the sub heararchy.
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	getAnalysisBits() Get the analysis bits for this path component, as defined in the WalkerFactory.
int	getAxis() Returns the axis being iterated, if it is known.
DTM	getDTM(int node) Get the DTM for this walker.
int	getLastPos(XPathContext xctxt) Get the number of nodes in the node list, which, in the XSLT 1 based counting system, is the last index position.
protected int	getNextNode() Get the next node in document order on the axes.
AxesWalker	getNextWalker() Get the next walker 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.
int	nextNode() Moves the TreeWalker to the next visible node in document order relative to the current node, and returns the new node.
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 org.htmlunit.xpath.axes.PredicatedNodeTest

acceptNode, callPredicateVisitors, canTraverseOutsideSubtree, countProximityPosition, getPredicate, getPredicateCount, getProximityPosition, getProximityPosition, getProximityPosition, initPredicateInfo, initProximityPosition, isReverseAxes, nodeToString, resetProximityPositions, setLocPathIterator, setPredicateCount

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

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

Methods inherited from class org.htmlunit.xpath.Expression

asIterator, asNode, assertion, bool, error, execute, exprGetParent, exprSetParent, getColumnNumber, getExpressionOwner, getLineNumber, getPublicId, getSystemId, isSameClass, isStableNumber, num

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 final int m_axis

The traversal axis from where the nodes will be filtered.

m_traverser

protected 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 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:

TransformerException - if any

clone

public Object clone()
             throws CloneNotSupportedException

Overrides:

clone in class PredicatedNodeTest

Throws:

CloneNotSupportedException

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.

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.

getAnalysisBits

public int getAnalysisBits()

Get the analysis bits for this path component, as defined in the WalkerFactory.

Specified by:

getAnalysisBits in interface PathComponent

Returns:

One of WalkerFactory#BIT_DESCENDANT, etc.

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.

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.

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 number of nodes in the node list, which, in the XSLT 1 based counting system, is the last index position.

Specified by:

getLastPos in interface SubContextList

Specified by:

getLastPos in class PredicatedNodeTest

Parameters:

xctxt - The XPath runtime context.

Returns:

the number of nodes in the node list.

getDTM

public DTM getDTM(int node)

Get the DTM for this walker.

Returns:

Non-null reference to a DTM.

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.

callVisitors

public void callVisitors(XPathVisitor visitor)

This will traverse the hierarchy, calling the visitor for each member. If the called visitor method returns false, the subtree should not be called.

Specified by:

callVisitors in interface XPathVisitable

Overrides:

callVisitors in class NodeTest

Parameters:

visitor - The visitor whose appropriate method will be called.

deepEquals

public boolean deepEquals(Expression expr)

Compare this object with another object and see if they are equal, include the sub heararchy.

Overrides:

deepEquals in class PredicatedNodeTest

Parameters:

expr - Another expression object.

Returns:

true if this objects class and the expr object's class are the same, and the data contained within both objects are considered equal.