org.apache.xalan.xsltc.dom
Class MultiValuedNodeHeapIterator

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

All Implemented Interfaces:

java.lang.Cloneable, DTMAxisIterator

Direct Known Subclasses:

KeyIndex.KeyIndexIterator, UnionIterator

public abstract class MultiValuedNodeHeapIterator
extends DTMAxisIteratorBase

MultiValuedNodeHeapIterator takes a set of multi-valued heap nodes and produces a merged NodeSet in document order with duplicates removed.

Each multi-valued heap node (which might be a DTMAxisIterator, but that's not necessary) generates DTM node handles in document order. The class maintains the multi-valued heap nodes in a heap, not surprisingly, sorted by the next DTM node handle available form the heap node.

After a DTM node is pulled from the heap node that's at the top of the heap, the heap node is advanced to the next DTM node handle it makes available, and the heap nature of the heap is restored to ensure the next DTM node handle pulled is next in document order overall.

Nested Class Summary

class

MultiValuedNodeHeapIterator.HeapNode An abstract representation of a set of nodes that will be retrieved in document order.

Field Summary

private int	_cachedHeapSize
private int	_cachedReturnedLast
private int	_free
private MultiValuedNodeHeapIterator.HeapNode[]	_heap
private int	_heapSize
private int	_returnedLast
private int	_size
private static int	InitSize

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

MultiValuedNodeHeapIterator()

Method Summary

protected void	addHeapNode(MultiValuedNodeHeapIterator.HeapNode node)
DTMAxisIterator	cloneIterator() Returns a deep copy of this iterator.
void	gotoMark() Restores the current node remembered by setMark().
private void	heapify(int i)
protected void	init()
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().
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, getLast, getNodeByPosition, getPosition, getStartNode, includeSelf, isDocOrdered, isReverse, resetPosition, returnNode, setRestartable

Methods inherited from class java.lang.Object

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

Field Detail

InitSize

private static final int InitSize

See Also:

Constant Field Values

_heapSize

private int _heapSize

_size

private int _size

_heap

private MultiValuedNodeHeapIterator.HeapNode[] _heap

_free

private int _free

_returnedLast

private int _returnedLast

_cachedReturnedLast

private int _cachedReturnedLast

_cachedHeapSize

private int _cachedHeapSize

Constructor Detail

MultiValuedNodeHeapIterator

public MultiValuedNodeHeapIterator()

Method Detail

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.

addHeapNode

protected void addHeapNode(MultiValuedNodeHeapIterator.HeapNode node)

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.

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.

init

protected void init()

heapify

private void heapify(int i)

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().

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.