public abstract class ValueSourceScorer extends Scorer
Scorer
which returns the result of FunctionValues.floatVal(int)
as
the score for a document, and which filters out documents that don't match matches(int)
.
This Scorer has a TwoPhaseIterator
. This is similar to FunctionQuery
,
but this one has no Weight
normalization factors/multipliers
and that one doesn't filter either.
Note: If the scores are needed, then the underlying value will probably be fetched/computed twice -- once to filter and next to return the score. If that's non-trivial then consider wrapping it in an implementation that will cache the current value.
FunctionQuery
Scorer.ChildScorer
Modifier and Type | Field and Description |
---|---|
protected FunctionValues |
values |
NO_MORE_DOCS
Modifier | Constructor and Description |
---|---|
protected |
ValueSourceScorer(IndexReader reader,
FunctionValues values) |
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, and returns the document number itself.
|
TwoPhaseIterator |
asTwoPhaseIterator()
Optional method: Return a
TwoPhaseIterator view of this
Scorer . |
long |
cost()
Returns the estimated cost of this
DocIdSetIterator . |
int |
docID()
Returns the following:
-1 if DocIdSetIterator.nextDoc() or
DocIdSetIterator.advance(int) were not called yet. |
int |
freq()
Returns the freq of this Scorer on the current document
|
abstract boolean |
matches(int doc)
Override to decide if this document matches.
|
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.
|
getChildren, getWeight
all, empty, slowAdvance
protected final FunctionValues values
protected ValueSourceScorer(IndexReader reader, FunctionValues values)
public abstract boolean matches(int doc)
TwoPhaseIterator.matches()
.public TwoPhaseIterator asTwoPhaseIterator()
Scorer
TwoPhaseIterator
view of this
Scorer
. A return value of null
indicates that
two-phase iteration is not supported.
Note that the returned TwoPhaseIterator
's
approximation
must
advance synchronously with this iterator: advancing the approximation must
advance this iterator and vice-versa.
Implementing this method is typically useful on Scorer
s
that have a high per-document overhead in order to confirm matches.
The default implementation returns null
.asTwoPhaseIterator
in class Scorer
public int docID()
DocIdSetIterator
-1
if DocIdSetIterator.nextDoc()
or
DocIdSetIterator.advance(int)
were not called yet.
DocIdSetIterator.NO_MORE_DOCS
if the iterator has exhausted.
docID
in class DocIdSetIterator
public int nextDoc() throws IOException
DocIdSetIterator
DocIdSetIterator.NO_MORE_DOCS
if there are no more docs in the
set.nextDoc
in class DocIdSetIterator
IOException
public int advance(int target) throws IOException
DocIdSetIterator
DocIdSetIterator.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 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.
advance
in class DocIdSetIterator
IOException
public float score() throws IOException
Scorer
DocIdSetIterator.nextDoc()
or DocIdSetIterator.advance(int)
is called the first time, or when called from within
LeafCollector.collect(int)
.score
in class Scorer
IOException
public int freq() throws IOException
Scorer
freq
in class Scorer
IOException
public long cost()
DocIdSetIterator
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.
cost
in class DocIdSetIterator
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