public abstract class DocIdSetIterator extends Object
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.Modifier and Type | Field and Description |
---|---|
static int |
NO_MORE_DOCS
When returned by
nextDoc() , advance(int) and
docID() it means there are no more docs in the iterator. |
Constructor and Description |
---|
DocIdSetIterator() |
Modifier and Type | Method and Description |
---|---|
abstract int |
advance(int target)
Advances to the first beyond the current whose document number is greater
than or equal to target, and returns the document number itself.
|
static DocIdSetIterator |
all(int maxDoc)
A
DocIdSetIterator that matches all documents up to
maxDoc - 1 . |
abstract long |
cost()
Returns the estimated cost of this
DocIdSetIterator . |
abstract int |
docID()
|
static DocIdSetIterator |
empty()
An empty
DocIdSetIterator instance |
abstract 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: after the iterator has exhausted you should not call this method, as it may result in unpredicted behavior. |
static DocIdSetIterator |
range(int minDoc,
int maxDoc)
A
DocIdSetIterator that matches a range documents from
minDocID (inclusive) to maxDocID (exclusive). |
protected int |
slowAdvance(int target)
Slow (linear) implementation of
advance(int) relying on
nextDoc() to advance beyond the target position. |
public static final int NO_MORE_DOCS
nextDoc()
, advance(int)
and
docID()
it means there are no more docs in the iterator.public static final DocIdSetIterator empty()
DocIdSetIterator
instancepublic static final DocIdSetIterator all(int maxDoc)
DocIdSetIterator
that matches all documents up to
maxDoc - 1
.public static final DocIdSetIterator range(int minDoc, int maxDoc)
DocIdSetIterator
that matches a range documents from
minDocID (inclusive) to maxDocID (exclusive).public abstract int docID()
-1
if nextDoc()
or
advance(int)
were not called yet.
NO_MORE_DOCS
if the iterator has exhausted.
public abstract int nextDoc() throws IOException
NO_MORE_DOCS
if there are no more docs in the
set.IOException
public abstract int advance(int target) throws IOException
NO_MORE_DOCS
if target
is greater than the highest document number in the set.
The behavior of this method is undefined when called with
target ≤ current
, or after the iterator has exhausted.
Both cases may result in unpredicted behavior.
When target > current
it 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: this method may be called with NO_MORE_DOCS
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.
IOException
protected final int slowAdvance(int target) throws IOException
advance(int)
relying on
nextDoc()
to advance beyond the target position.IOException
public abstract long cost()
DocIdSetIterator
.
This is generally an upper bound of the number of documents this iterator might match, but may be a rough heuristic, hardcoded value, or otherwise completely inaccurate.
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