org.apache.xalan.xsltc.dom
Class MatchingIterator

java.lang.Object
  org.apache.xml.dtm.ref.DTMAxisIteratorBase
      org.apache.xalan.xsltc.dom.MatchingIterator

All Implemented Interfaces:

java.lang.Cloneable, DTMAxisIterator

public final class MatchingIterator
extends DTMAxisIteratorBase

This is a special kind of iterator that takes a source iterator and a node N. If initialized with a node M (the parent of N) it computes the position of N amongst the children of M. This position can be obtained by calling getPosition(). It is an iterator even though next() will never be called. It is used to match patterns with a single predicate like: BOOK[position() = last()] In this example, the source iterator will return elements of type BOOK, a call to position() will return the position of N. Notice that because of the way the pattern matching is implemented, N will always be a node in the source since (i) it is a BOOK or the test sequence would not be considered and (ii) the source iterator is initialized with M which is the parent of N. Also, and still in this example, a call to last() will return the number of elements in the source (i.e. the number of BOOKs).

Field Summary

private int	_match The node to match.
private DTMAxisIterator	_source A reference to a source iterator.

Fields inherited from class org.apache.xml.dtm.ref.DTMAxisIteratorBase

_includeSelf, _isRestartable, _last, _markedNode, _position, _startNode

Fields inherited from interface org.apache.xml.dtm.DTMAxisIterator

END

Constructor Summary

MatchingIterator(int match, DTMAxisIterator source)

Method Summary

DTMAxisIterator	cloneIterator() Returns a deep copy of this iterator.
int	getLast() Returns the position of the last node within the iteration, as defined by XPath.
int	getPosition()
void	gotoMark() Restores the current node remembered by setMark().
int	next() Get the next node in the iteration.
DTMAxisIterator	reset() Resets the iterator to the last start node.
void	setMark() Remembers the current node for the next call to gotoMark().
void	setRestartable(boolean isRestartable) Set if restartable.
DTMAxisIterator	setStartNode(int node) Set start to END should 'close' the iterator, i.e.

Methods inherited from class org.apache.xml.dtm.ref.DTMAxisIteratorBase

getAxis, getNodeByPosition, getStartNode, includeSelf, isDocOrdered, isReverse, resetPosition, returnNode

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

_source

private DTMAxisIterator _source

A reference to a source iterator.

_match

private final int _match

The node to match.

Constructor Detail

MatchingIterator

public MatchingIterator(int match,
                        DTMAxisIterator source)

Method Detail

setRestartable

public void setRestartable(boolean isRestartable)

Description copied from interface: DTMAxisIterator

Set if restartable.

Specified by:

setRestartable in interface DTMAxisIterator

Overrides:

setRestartable in class DTMAxisIteratorBase

cloneIterator

public DTMAxisIterator cloneIterator()

Description copied from class: DTMAxisIteratorBase

Returns a deep copy of this iterator. Cloned iterators may not be restartable. The iterator being cloned may or may not become non-restartable as a side effect of this operation.

Specified by:

cloneIterator in interface DTMAxisIterator

Overrides:

cloneIterator in class DTMAxisIteratorBase

Returns:

a deep copy of this iterator.

setStartNode

public DTMAxisIterator setStartNode(int node)

Description copied from interface: DTMAxisIterator

Set start to END should 'close' the iterator, i.e. subsequent call to next() should return END.

Parameters:

node - Sets the root of the iteration.

Returns:

A DTMAxisIterator set to the start of the iteration.

reset

public DTMAxisIterator reset()

Description copied from interface: DTMAxisIterator

Resets the iterator to the last start node.

Specified by:

reset in interface DTMAxisIterator

Overrides:

reset in class DTMAxisIteratorBase

Returns:

A DTMAxisIterator which has been reset to the start node, which may or may not be the same as this iterator.

next

public int next()

Description copied from interface: DTMAxisIterator

Get the next node in the iteration.

Returns:

The next node handle in the iteration, or END.

getLast

public int getLast()

Description copied from class: DTMAxisIteratorBase

Returns the position of the last node within the iteration, as defined by XPath. In a forward iterator, I believe this equals the number of nodes which this iterator will yield. In a reverse iterator, I believe it should return 1 (since the "last" is the first produced.) This may be an expensive operation when called the first time, since it may have to iterate through a large part of the document to produce its answer.

Specified by:

getLast in interface DTMAxisIterator

Overrides:

getLast in class DTMAxisIteratorBase

Returns:

The number of nodes in this iterator (forward) or 1 (reverse).

getPosition

public int getPosition()

Specified by:

getPosition in interface DTMAxisIterator

Overrides:

getPosition in class DTMAxisIteratorBase

Returns:

The position of the current node within the set, as defined by XPath. Note that this is one-based, not zero-based.

setMark

public void setMark()

Description copied from interface: DTMAxisIterator

Remembers the current node for the next call to gotoMark().

gotoMark

public void gotoMark()

Description copied from interface: DTMAxisIterator

Restores the current node remembered by setMark().