/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
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 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
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 * See the License for the specific language governing permissions and
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package org.apache.lucene.search;


import java.io.IOException;
import java.util.Set;

import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.index.Term;

A Weight that has a constant score equal to the boost of the wrapped query. This is typically useful when building queries which do not produce meaningful scores and are mostly useful for filtering.
@lucene.internal
/** * A Weight that has a constant score equal to the boost of the wrapped query. * This is typically useful when building queries which do not produce * meaningful scores and are mostly useful for filtering. * * @lucene.internal */
public abstract class ConstantScoreWeight extends Weight { private final float score; protected ConstantScoreWeight(Query query, float score) { super(query); this.score = score; } @Override public void extractTerms(Set<Term> terms) { // most constant-score queries don't wrap index terms // eg. geo filters, doc values queries, ... // override if your constant-score query does wrap terms }
Return the score produced by this Weight.
/** Return the score produced by this {@link Weight}. */
protected final float score() { return score; } @Override public Explanation explain(LeafReaderContext context, int doc) throws IOException { final Scorer s = scorer(context); final boolean exists; if (s == null) { exists = false; } else { final TwoPhaseIterator twoPhase = s.twoPhaseIterator(); if (twoPhase == null) { exists = s.iterator().advance(doc) == doc; } else { exists = twoPhase.approximation().advance(doc) == doc && twoPhase.matches(); } } if (exists) { return Explanation.match( score, getQuery().toString() + (score == 1f ? "" : "^" + score)); } else { return Explanation.noMatch(getQuery().toString() + " doesn't match id " + doc); } } }