public abstract class Weight extends Object implements Serializable
The purpose of
Weight is to ensure searching does not
Query, so that a
Query instance can be reused.
Searcher dependent state of the query should reside in the
IndexReader dependent state should reside in the
Weight is used in the following way:
Weightis constructed by a top-level query, given a
sumOfSquaredWeights()method is called on the
Weightto compute the query normalization factor
Similarity.queryNorm(float)of the query clauses contained in the query.
normalize(float). At this point the weighting is complete.
Scoreris constructed by
|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 weight for this query.
Assigns the query normalization factor to this.
Returns true iff this implementation scores docs only out of order.
The sum of squared weights of contained query clauses.
public abstract Explanation explain(IndexReader reader, int doc) throws IOException
reader- sub-reader containing the give doc
public abstract Query getQuery()
public abstract float getValue()
public abstract void normalize(float norm)
public abstract Scorer scorer(IndexReader reader, boolean scoreDocsInOrder, boolean topScorer) 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.
IndexReaderfor 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.
Scorerwhich scores documents in/out-of order.
public abstract float sumOfSquaredWeights() throws IOException
public boolean scoresDocsOutOfOrder()
scorer(org.apache.lucene.index.IndexReader, boolean, boolean)to create a matching
Scorerinstance for a given
Collector, or vice versa.
NOTE: the default implementation returns
Scorer scores documents in-order.