org.apache.lucene.search

Class DocIdSetIterator

java.lang.Object

org.apache.lucene.search.DocIdSetIterator

Direct Known Subclasses:

FieldCacheTermsFilter.FieldCacheTermsFilterDocIdSet.FieldCacheTermsFilterDocIdSetIterator, FilteredDocIdSetIterator, OpenBitSetIterator, Scorer

public abstract class DocIdSetIterator
extends Object

This abstract class defines methods to iterate over a set of non-decreasing doc ids. Note that this class assumes it iterates on doc Ids, and therefore NO_MORE_DOCS is set to 2147483647 in order to be used as a sentinel object. Implementations of this class are expected to consider Integer.MAX_VALUE as an invalid value.

Field Summary

Fields

Modifier and Type	Field and Description
static int	NO_MORE_DOCS When returned by nextDoc(), advance(int) and doc() it means there are no more docs in the iterator.

Constructor Summary

Constructors

Constructor and Description
DocIdSetIterator()

Method Summary

Methods

Modifier and Type	Method and Description
int	advance(int target) Advances to the first beyond the current whose document number is greater than or equal to target.
int	doc() Deprecated. use docID() instead.
int	docID() Returns the following: -1 or NO_MORE_DOCS if nextDoc() or advance(int) were not called yet.
boolean	next() Deprecated. use nextDoc() instead. This will be removed in 3.0
int	nextDoc() Advances to the next document in the set and returns the doc it is currently on, or NO_MORE_DOCS if there are no more docs in the set. NOTE: in 3.0 this method will become abstract, following the removal of next().
boolean	skipTo(int target) Deprecated. use advance(int) instead. This will be removed in 3.0

Methods inherited from class java.lang.Object

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

Field Detail

NO_MORE_DOCS

public static final int NO_MORE_DOCS

When returned by nextDoc(), advance(int) and doc() it means there are no more docs in the iterator.

See Also:

Constant Field Values

Constructor Detail

DocIdSetIterator

public DocIdSetIterator()

Method Detail

doc

public int doc()

Deprecated. use docID() instead.

Unsupported anymore. Call docID() instead. This method throws UnsupportedOperationException if called.

docID

public int docID()

Returns the following:

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

NOTE: in 3.0, this method will become abstract.

Since:

2.9

next

public boolean next()
             throws IOException

Deprecated. use nextDoc() instead. This will be removed in 3.0

Unsupported anymore. Call nextDoc() instead. This method throws UnsupportedOperationException if called.

Throws:

IOException

skipTo

public boolean skipTo(int target)
               throws IOException

Deprecated. use advance(int) instead. This will be removed in 3.0

Unsupported anymore. Call advance(int) instead. This method throws UnsupportedOperationException if called.

Throws:

IOException

nextDoc

public int nextDoc()
            throws IOException

Advances to the next document in the set and returns the doc it is currently on, or NO_MORE_DOCS if there are no more docs in the set.
NOTE: in 3.0 this method will become abstract, following the removal of next(). For backward compatibility it is implemented as:

 public int nextDoc() throws IOException {
   return next() ? doc() : NO_MORE_DOCS;
 }
 

NOTE: after the iterator has exhausted you should not call this method, as it may result in unpredicted behavior.

Throws:

IOException

Since:

2.9

advance

public int advance(int target)
            throws IOException

Advances to the first beyond the current whose document number is greater than or equal to target. Returns the current document number or NO_MORE_DOCS if there are no more docs in the set.

Behaves as if written:

 int advance(int target) {
   int doc;
   while ((doc = nextDoc()) < target) {
   }
   return doc;
 }
 

Some implementations are considerably more efficient than that.

NOTE: certain implementations may return a different value (each time) if called several times in a row with the same target.

NOTE: this method may be called with 2147483647 for efficiency by some Scorers. If your implementation cannot efficiently determine that it should exhaust, it is recommended that you check for that value in each call to this method.

NOTE: after the iterator has exhausted you should not call this method, as it may result in unpredicted behavior.

NOTE: in 3.0 this method will become abstract, following the removal of skipTo(int).

Throws:

IOException

Since:

2.9