org.htmlunit.xpath.axes

Class DescendantIterator

java.lang.Object

org.htmlunit.xpath.Expression

org.htmlunit.xpath.patterns.NodeTest

org.htmlunit.xpath.axes.PredicatedNodeTest

org.htmlunit.xpath.axes.LocPathIterator

org.htmlunit.xpath.axes.DescendantIterator

All Implemented Interfaces:

Cloneable, SourceLocator, PathComponent, SubContextList, ExpressionNode, DTMIterator, XPathVisitable

public class DescendantIterator
extends LocPathIterator

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

See Also:

LocPathIterator

Field Summary

Fields

Modifier and Type	Field and Description
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.htmlunit.xpath.axes.LocPathIterator

m_cdtm, m_clones, m_context, m_currentContextNode, m_execContext, m_lastFetched, m_length, m_pos

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

Fields inherited from interface org.htmlunit.xpath.xml.dtm.DTMIterator

FILTER_ACCEPT, FILTER_SKIP

Method Summary

Modifier and Type	Method and Description
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 start of the iteration.
boolean	deepEquals(Expression expr) Compare this object with another object and see if they are equal, include the sub heararchy.
void	detach() Detaches the DTMIterator 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) Reset the root node of the DTMIterator, overriding the value specified when it was created.

Methods inherited from class org.htmlunit.xpath.axes.LocPathIterator

asIterator, bool, callVisitors, execute, getAnalysisBits, getCurrentNode, getCurrentPos, getDTM, getDTMManager, getExpandEntityReferences, getIsTopLevel, getLastPos, getLength, getPrefixResolver, getRoot, getWhatToShow, getXPathContext, incrementCurrentPos, isDocOrdered, isFresh, item, previousNode, reset, returnNextNode, runTo, setCurrentPos, setIsTopLevel, setShouldCacheNodes

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

acceptNode, callPredicateVisitors, canTraverseOutsideSubtree, clone, 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, getLocalName, getNamespace, getNodeTypeTest, getStaticScore, initNodeTest, initNodeTest, setLocalName, setNamespace, setStaticScore, setWhatToShow

Methods inherited from class org.htmlunit.xpath.Expression

assertion, 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

Methods inherited from interface org.htmlunit.xpath.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.

Method Detail

cloneWithReset

public DTMIterator cloneWithReset()
                           throws CloneNotSupportedException

Get a cloned Iterator that is reset to the start of the iteration.

Specified by:

cloneWithReset in interface DTMIterator

Overrides:

cloneWithReset in class LocPathIterator

Returns:

A clone of this iteration that has been reset.

Throws:

CloneNotSupportedException - if any

nextNode

public int nextNode()

Returns the next node in the set and advances the position of the iterator in the set. After a DTMIterator has setRoot called, the first call to nextNode() returns that root or (if it is rejected by the filters) the first node within its subtree which is not filtered out.

Specified by:

nextNode in interface DTMIterator

Specified by:

nextNode in class LocPathIterator

Returns:

The next node handle in the set being iterated over, or DTM.NULL if there are no more members in that set.

setRoot

public void setRoot(int context,
                    Object environment)

Reset the root node of the DTMIterator, overriding the value specified when it was created. Note the root node is not the root node of the document tree, but the context node from where the iteration begins.

Specified by:

setRoot in interface DTMIterator

Overrides:

setRoot in class LocPathIterator

Parameters:

context - int Handle of the context node.

environment - The environment object. 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.

asNode

public int asNode(XPathContext xctxt)
           throws TransformerException

Return the first node out of the nodeset, if this expression is a nodeset expression.

Overrides:

asNode in class LocPathIterator

Parameters:

xctxt - The XPath runtime context.

Returns:

the first node out of the nodeset, or DTM.NULL.

Throws:

TransformerException - if any

detach

public void detach()

Detaches the DTMIterator from the set which it iterated over, releasing any computational resources and placing the iterator in the INVALID state. After detach has been invoked, calls to nextNode or previousNode will raise a runtime exception.

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)

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.