org.apache.xpath.axes

Class FilterExprWalker

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.FilterExprWalker

All Implemented Interfaces:

Serializable, Cloneable, SourceLocator, PathComponent, SubContextList, ExpressionNode, ExpressionOwner, XPathVisitable

public class FilterExprWalker
extends AxesWalker

Walker for the OP_VARIABLE, or OP_EXTFUNCTION, or OP_FUNCTION, or OP_GROUP, op codes.

See Also:

XPath FilterExpr descriptions, Serialized Form

Field Summary

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

m_axis, m_nextWalker, m_traverser

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

m_foundLast, m_lpi, m_predCount, 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

Constructors

Constructor and Description
FilterExprWalker(WalkingIterator locPathIterator) Construct a FilterExprWalker using a LocPathIterator.

Method Summary

Modifier and Type	Method and Description
short	acceptNode(int n) This method needs to override AxesWalker.acceptNode because FilterExprWalkers don't need to, and shouldn't, do a node test.
void	callPredicateVisitors(XPathVisitor visitor) This will traverse the heararchy, calling the visitor for each member.
Object	clone() Get a cloned FilterExprWalker.
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.
void	fixupVariables(Vector vars, int globalsSize) This function is used to fixup variables from QNames to stack frame indexes at stylesheet build time.
int	getAnalysisBits() Get the analysis bits for this walker, as defined in the WalkerFactory.
int	getAxis() Returns the axis being iterated, if it is known.
Expression	getInnerExpression() Get the inner contained expression of this filter.
int	getLastPos(XPathContext xctxt) Get the index of the last node that can be itterated to.
int	getNextNode() Moves the TreeWalker to the next visible node in document order relative to the current node, and returns the new node.
void	init(Compiler compiler, int opPos, int stepType) Init a FilterExprWalker.
boolean	isDocOrdered() Returns true if all the nodes in the iteration well be returned in document order.
void	setInnerExpression(Expression expr) Set the inner contained expression of this filter.
void	setRoot(int root) Set the root node of the TreeWalker.

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

callVisitors, getCurrentNode, getDTM, getExpression, getNextWalker, getPrevWalker, getRoot, nextNode, setDefaultDTM, setExpression, setNextWalker, setPrevWalker, wi

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

canTraverseOutsideSubtree, countProximityPosition, 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, 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

Constructor Detail

FilterExprWalker

public FilterExprWalker(WalkingIterator locPathIterator)

Construct a FilterExprWalker using a LocPathIterator.

Parameters:

locPathIterator - non-null reference to the parent iterator.

Method Detail

init

public void init(Compiler compiler,
                 int opPos,
                 int stepType)
          throws TransformerException

Init a FilterExprWalker.

Overrides:

init in class AxesWalker

Parameters:

compiler - non-null reference to the Compiler that is constructing.

opPos - positive opcode position for this step.

stepType - The type of step.

Throws:

TransformerException

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

setRoot

public void setRoot(int root)

Set the root node of the TreeWalker.

Overrides:

setRoot in class AxesWalker

Parameters:

root - non-null reference to the root, or starting point of the query.

clone

public Object clone()
             throws CloneNotSupportedException

Get a cloned FilterExprWalker.

Overrides:

clone in class AxesWalker

Returns:

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

Throws:

CloneNotSupportedException

acceptNode

public short acceptNode(int n)

This method needs to override AxesWalker.acceptNode because FilterExprWalkers don't need to, and shouldn't, do a node test.

Overrides:

acceptNode in class PredicatedNodeTest

Parameters:

n - The node to check to see if it passes the filter or not.

Returns:

a constant to determine whether the node is accepted, rejected, or skipped, as defined above .

getNextNode

public int getNextNode()

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.

Overrides:

getNextNode in class AxesWalker

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.

Specified by:

getLastPos in interface SubContextList

Overrides:

getLastPos in class AxesWalker

Parameters:

xctxt - XPath runtime context.

Returns:

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

fixupVariables

public void fixupVariables(Vector vars,
                           int globalsSize)

This function is used to fixup variables from QNames to stack frame indexes at stylesheet build time.

Overrides:

fixupVariables in class PredicatedNodeTest

Parameters:

vars - List of QNames that correspond to variables. This list should be searched backwards for the first qualified name that corresponds to the variable reference qname. The position of the QName in the vector from the start of the vector will be its position in the stack frame (but variables above the globalsTop value will need to be offset to the current stack frame).

getInnerExpression

public Expression getInnerExpression()

Get the inner contained expression of this filter.

setInnerExpression

public void setInnerExpression(Expression expr)

Set the inner contained expression of this filter.

getAnalysisBits

public int getAnalysisBits()

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

Specified by:

getAnalysisBits in interface PathComponent

Overrides:

getAnalysisBits in class AxesWalker

Returns:

One of WalkerFactory#BIT_DESCENDANT, etc.

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:

true as a default.

getAxis

public int getAxis()

Returns the axis being iterated, if it is known.

Overrides:

getAxis in class AxesWalker

Returns:

Axis.CHILD, etc., or -1 if the axis is not known or is of multiple types.

callPredicateVisitors

public void callPredicateVisitors(XPathVisitor visitor)

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

Overrides:

callPredicateVisitors in class PredicatedNodeTest

Parameters:

visitor - The visitor whose appropriate method will be called.

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 AxesWalker

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.

See Also:

Expression.deepEquals(Expression)