org.apache.xalan.xsltc.dom
Class MultiValuedNodeHeapIterator

java.lang.Object
  extended by org.apache.xml.dtm.ref.DTMAxisIteratorBase
      extended by 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.