public class ScoreCachingWrappingScorer extends Scorer
Scorer which wraps another scorer and caches the score of the
current document. Successive calls to score() will return the same
result and will not invoke the wrapped Scorer's score() method, unless the
current document has changed.Collector
interface, in which the score is not computed for a document by default, only
if the collector requests it. Some collectors may need to use the score in
several places, however all they have in hand is a Scorer object, and
might end up computing the score of a document more than once.NO_MORE_DOCS| Constructor and Description |
|---|
ScoreCachingWrappingScorer(Scorer scorer)
Creates a new instance by wrapping the given scorer.
|
| Modifier and Type | Method and Description |
|---|---|
int |
advance(int target)
Advances to the first beyond (see NOTE below) the current whose document
number is greater than or equal to target.
|
int |
docID()
Returns the following:
-1 or
DocIdSetIterator.NO_MORE_DOCS if DocIdSetIterator.nextDoc() or
DocIdSetIterator.advance(int) were not called yet. |
Similarity |
getSimilarity()
Returns the Similarity implementation used by this scorer.
|
int |
nextDoc()
Advances to the next document in the set and returns the doc it is
currently on, or
DocIdSetIterator.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. |
float |
score()
Returns the score of the current document matching the query.
|
void |
score(Collector collector)
Scores and collects all matching documents.
|
protected boolean |
score(Collector collector,
int max,
int firstDocID)
Expert: Collects matching documents in a range.
|
freq, visitScorers, visitSubScorerspublic ScoreCachingWrappingScorer(Scorer scorer)
protected boolean score(Collector collector, int max, int firstDocID) throws IOException
ScorerfirstDocID is added to ensure that DocIdSetIterator.nextDoc()
was called before this method.
NOTE: Because of backwards compatibility, this method is still
declared as protected, but it is intended to be public,
because it's called from other classes (like BooleanScorer).
If you subclass Scorer, you should declare the overridden method
as public to ease transition to Lucene 4.0, where it will be public.
score in class Scorercollector - The collector to which all matching documents are passed.max - Do not score documents past this.firstDocID - The first document ID (ensures DocIdSetIterator.nextDoc() is called before
this method.IOExceptionpublic Similarity getSimilarity()
ScorergetSimilarity in class Scorerpublic float score()
throws IOException
ScorerDocIdSetIterator.nextDoc() or DocIdSetIterator.advance(int)
is called the first time, or when called from within
Collector.collect(int).score in class ScorerIOExceptionpublic int docID()
DocIdSetIteratorDocIdSetIterator.NO_MORE_DOCS if DocIdSetIterator.nextDoc() or
DocIdSetIterator.advance(int) were not called yet.
DocIdSetIterator.NO_MORE_DOCS if the iterator has exhausted.
docID in class DocIdSetIteratorpublic int nextDoc()
throws IOException
DocIdSetIteratorDocIdSetIterator.NO_MORE_DOCS if there are no more docs in the
set.nextDoc in class DocIdSetIteratorIOExceptionpublic void score(Collector collector) throws IOException
Scorerscore in class Scorercollector - The collector to which all matching documents are passed.IOExceptionpublic int advance(int target)
throws IOException
DocIdSetIteratorDocIdSetIterator.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: when target ≤ current implementations may opt
not to advance beyond their current DocIdSetIterator.docID().
NOTE: this method may be called with DocIdSetIterator.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.
NOTE: after the iterator has exhausted you should not call this method, as it may result in unpredicted behavior.
advance in class DocIdSetIteratorIOExceptionCopyright © 2000-2012 Apache Software Foundation. All Rights Reserved.