| /* |
| * 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 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| 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 |
| */ |
| 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 {@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); |
| } |
| } |
| |
| } |