org.apache.xpath.axes

Class UnionPathIterator

public class UnionPathIterator extends LocPathIterator implements Cloneable, DTMIterator, Serializable, PathComponent

This class extends NodeSetDTM, which implements DTMIterator, and fetches nodes one at a time in document order based on a XPath UnionExpr. As each node is iterated via nextNode(), the node is also stored in the NodeVector, so that previousNode() can easily be done.

UNKNOWN: advanced

Constructor Summary
UnionPathIterator()
Constructor to create an instance which you can add location paths to.
UnionPathIterator(Compiler compiler, int opPos)
Create a UnionPathIterator object, including creation of location path iterators from the opcode list, and call back into the Compiler to create predicate expressions.
Method Summary
voidaddIterator(DTMIterator expr)
Add an iterator to the union list.
voidcallVisitors(ExpressionOwner owner, XPathVisitor visitor)
Objectclone()
Get a cloned LocPathIterator that holds the same position as this iterator.
static LocPathIteratorcreateUnionIterator(Compiler compiler, int opPos)
This will return an iterator capable of handling the union of paths given.
booleandeepEquals(Expression expr)
voiddetach()
Detaches the iterator 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.
intnextNode()
Returns the next node in the set and advances the position of the iterator in the set.
voidsetRoot(int context, Object environment)
Initialize the context values for this expression after it is cloned.

Constructor Detail

UnionPathIterator

public UnionPathIterator()
Constructor to create an instance which you can add location paths to.

UnionPathIterator

public UnionPathIterator(Compiler compiler, int opPos)
Create a UnionPathIterator object, including creation of location path iterators from the opcode list, and call back into the Compiler to create predicate expressions.

Parameters: compiler The Compiler which is creating this expression. opPos The position of this iterator in the opcode list from the compiler.

Throws: javax.xml.transform.TransformerException

Method Detail

addIterator

public void addIterator(DTMIterator expr)
Add an iterator to the union list.

Parameters: expr non-null reference to a location path iterator.

callVisitors

public void callVisitors(ExpressionOwner owner, XPathVisitor visitor)

See Also: XPathVisitable

clone

public Object clone()
Get a cloned LocPathIterator that holds the same position as this iterator.

Returns: A clone of this iterator that holds the same node position.

Throws: CloneNotSupportedException

createUnionIterator

public static LocPathIterator createUnionIterator(Compiler compiler, int opPos)
This will return an iterator capable of handling the union of paths given.

Parameters: compiler The Compiler which is creating this expression. opPos The position of this iterator in the opcode list from the compiler.

Returns: Object that is derived from LocPathIterator.

Throws: javax.xml.transform.TransformerException

deepEquals

public boolean deepEquals(Expression expr)

See Also: deepEquals

detach

public void detach()
Detaches the iterator from the set which it iterated over, releasing any computational resources and placing the iterator in the INVALID state. Afterdetach has been invoked, calls to nextNode orpreviousNode will raise the exception INVALID_STATE_ERR.

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.

nextNode

public int nextNode()
Returns the next node in the set and advances the position of the iterator in the set. After a DTMIterator is created, the first call to nextNode() returns the first node in the set.

Returns: The next Node in the set being iterated over, or null if there are no more members in that set.

setRoot

public void setRoot(int context, Object environment)
Initialize the context values for this expression after it is cloned.

Parameters: context The XPath runtime context for this transformation.

Copyright B) 2006 Apache XML Project. All Rights Reserved.