public abstract class Weight extends Object
The purpose of
Weight is to ensure searching does not modify a
Query, so that a
Query instance can be reused.
IndexSearcher dependent state of the query should reside in the
AtomicReader dependent state should reside in the
Scorer instances for a given
boolean, boolean, Bits))
callers must maintain the relationship between the searcher's top-level
IndexReaderContext and the context used to create a
Weight is used in the following way:
Weightis constructed by a top-level query, given a
getValueForNormalization()method is called on the
Weightto compute the query normalization factor
Similarity.queryNorm(float)of the query clauses contained in the query.
normalize(float, float). At this point the weighting is complete.
Scoreris constructed by
scorer(AtomicReaderContext, boolean, boolean, Bits).
|Constructor and Description|
|Modifier and Type||Method and Description|
An explanation of the score computation for the named document.
The query that this concerns.
The value for normalization of contained query clauses (e.g.
Assigns the query normalization factor and boost from parent queries to this.
Returns true iff this implementation scores docs only out of order.
public abstract Explanation explain(AtomicReaderContext context, int doc) throws IOException
context- the readers context to create the
doc- the document's id relative to the given context's reader
IOException- if an
public abstract Query getQuery()
public abstract float getValueForNormalization() throws IOException
public abstract void normalize(float norm, float topLevelBoost)
public abstract Scorer scorer(AtomicReaderContext context, boolean scoreDocsInOrder, boolean topScorer, Bits acceptDocs) throws IOException
Scorerwhich scores documents in/out-of order according to
NOTE: even if
scoreDocsInOrder is false, it is
recommended to check whether the returned
Scorer indeed scores
documents out of order (i.e., call
Scorer implementations will always return documents
NOTE: null can be returned if no documents will be scored by this query.
AtomicReaderContextfor which to return the
scoreDocsInOrder- specifies whether in-order scoring of documents is required. Note that if set to false (i.e., out-of-order scoring is required), this method can return whatever scoring mode it supports, as every in-order scorer is also an out-of-order one. However, an out-of-order scorer may not support
DocIdSetIterator.advance(int), therefore it is recommended to request an in-order scorer if use of these methods is required.
topScorer- if true,
Scorer.score(Collector)will be called; if false,
DocIdSetIterator.advance(int)will be called.
acceptDocs- Bits that represent the allowable docs to match (typically deleted docs but possibly filtering other documents)
Scorerwhich scores documents in/out-of order.
IOException- if there is a low-level I/O error
public boolean scoresDocsOutOfOrder()
scorer(AtomicReaderContext, boolean, boolean, Bits)to create a matching
Scorerinstance for a given
Collector, or vice versa.
NOTE: the default implementation returns
Scorer scores documents in-order.
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