org.sindice.siren.index

Interface DocsAndNodesIterator

All Known Implementing Classes:

ConstrainedNodesEnum, DocsNodesAndPositionsEnum, IntervalConstrainedNodesEnum, LevelConstrainedNodesEnum, MappingMultiDocsNodesAndPositionsEnum, MultiDocsNodesAndPositionsEnum, SingleIntervalConstrainedNodesEnum

public interface DocsAndNodesIterator

Interface that defines methods to iterate over a set of increasing doc identifiers and node labels.

This class iterates on doc ids and node labels. The sentinel value NO_MORE_DOC (which is set to 2147483647) is used to indicate the end of the document stream. The sentinel value NO_MORE_NOD (which is set to [2147483647]) is used to indicate the end of a node stream.

Field Summary

Fields

Modifier and Type	Field and Description
static int	NO_MORE_DOC When returned by doc() it means there are no more docs in the iterator.
static org.apache.lucene.util.IntsRef	NO_MORE_NOD When returned by node() it means there are no more nodes in the iterator.

Method Summary

Methods

Modifier and Type	Method and Description
int	doc() Returns the following: -1 or NO_MORE_DOC if nextDocument() or skipTo(int) were not called yet.
boolean	nextDocument() Advances to the next document in the set.
boolean	nextNode() Move to the next node path in the current document.
org.apache.lucene.util.IntsRef	node() Returns the following: -1 or NO_MORE_NOD if nextNode() or #skipTo(int, int[]) were not called yet.
boolean	skipTo(int target) Skip to the first document beyond (see NOTE below) the current whose number is greater than or equal to target.

Field Detail

NO_MORE_DOC

static final int NO_MORE_DOC

When returned by doc() it means there are no more docs in the iterator.

See Also:

Constant Field Values

NO_MORE_NOD

static final org.apache.lucene.util.IntsRef NO_MORE_NOD

When returned by node() it means there are no more nodes in the iterator.

Method Detail

nextDocument

boolean nextDocument()
                     throws IOException

Advances to the next document in the set.

Returns:

false if there is no more docs in the set.

Throws:

IOException

nextNode

boolean nextNode()
                 throws IOException

Move to the next node path in the current document.

Should not be called until nextDocument() or skipTo(int) are called for the first time.

Returns:

false if there is no more node for the current document or if nextDocument() or skipTo(int) were not called yet.

Throws:

IOException

skipTo

boolean skipTo(int target)
               throws IOException

Skip to the first document beyond (see NOTE below) the current whose number is greater than or equal to target. Returns false if there are no more docs in the set.

Behaves as if written:

 boolean skipTo(int target) {
   while (nextDocument()) {
     if (target ≤ doc())
       return true;
   }
   return false;
 }
 

Some implementations are considerably more efficient than that.

NOTE: when target ≤ current implementations must not advance beyond their current doc().

Throws:

IOException

doc

int doc()

Returns the following:

• -1 or NO_MORE_DOC if nextDocument() or skipTo(int) were not called yet.
• NO_MORE_DOC if the iterator has exhausted.
• Otherwise it should return the doc ID it is currently on.

node

org.apache.lucene.util.IntsRef node()

Returns the following:

• -1 or NO_MORE_NOD if nextNode() or #skipTo(int, int[]) were not called yet.
• NO_MORE_NOD if the iterator has exhausted.
• Otherwise it should return the node it is currently on.