org.apache.xpath.axes

Class FilterExprWalker

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

Constructor Summary
FilterExprWalker(WalkingIterator locPathIterator)
Construct a FilterExprWalker using a LocPathIterator.
Method Summary
shortacceptNode(int n)
This method needs to override AxesWalker.acceptNode because FilterExprWalkers don't need to, and shouldn't, do a node test.
voidcallPredicateVisitors(XPathVisitor visitor)
This will traverse the heararchy, calling the visitor for each member.
Objectclone()
Get a cloned FilterExprWalker.
booleandeepEquals(Expression expr)
voiddetach()
Detaches the walker from the set which it iterated over, releasing any computational resources and placing the iterator in the INVALID state.
voidfixupVariables(Vector vars, int globalsSize)
This function is used to fixup variables from QNames to stack frame indexes at stylesheet build time.
intgetAnalysisBits()
Get the analysis bits for this walker, as defined in the WalkerFactory.
intgetAxis()
Returns the axis being iterated, if it is known.
ExpressiongetInnerExpression()
Get the inner contained expression of this filter.
intgetLastPos(XPathContext xctxt)
Get the index of the last node that can be itterated to.
intgetNextNode()
Moves the TreeWalker to the next visible node in document order relative to the current node, and returns the new node.
voidinit(Compiler compiler, int opPos, int stepType)
Init a FilterExprWalker.
booleanisDocOrdered()
Returns true if all the nodes in the iteration well be returned in document order.
voidsetInnerExpression(Expression expr)
Set the inner contained expression of this filter.
voidsetRoot(int root)
Set the root node of the TreeWalker.

Constructor Detail

FilterExprWalker

public FilterExprWalker(WalkingIterator locPathIterator)
Construct a FilterExprWalker using a LocPathIterator.

Parameters: locPathIterator non-null reference to the parent iterator.

Method Detail

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.

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 .

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.

Parameters: visitor The visitor whose appropriate method will be called.

clone

public Object clone()
Get a cloned FilterExprWalker.

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

Throws: CloneNotSupportedException

deepEquals

public boolean deepEquals(Expression expr)

See Also: deepEquals

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.

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.

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).

getAnalysisBits

public int getAnalysisBits()
Get the analysis bits for this walker, as defined in the WalkerFactory.

Returns: One of WalkerFactory#BIT_DESCENDANT, etc.

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.

getInnerExpression

public Expression getInnerExpression()
Get the inner contained expression of this filter.

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.

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.

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

init

public void init(Compiler compiler, int opPos, int stepType)
Init a FilterExprWalker.

Parameters: compiler non-null reference to the Compiler that is constructing. opPos positive opcode position for this step. stepType The type of step.

Throws: javax.xml.transform.TransformerException

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.

setInnerExpression

public void setInnerExpression(Expression expr)
Set the inner contained expression of this filter.

setRoot

public void setRoot(int root)
Set the root node of the TreeWalker.

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

Copyright © 2005 Apache XML Project. All Rights Reserved.