| package org.apache.lucene.search; |
| |
| /* |
| * 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. |
| */ |
| |
| import java.io.IOException; |
| import java.util.Collection; |
| import java.util.Collections; |
| |
| /** |
| * A {@link Scorer} which wraps another scorer and caches the score of the |
| * current document. Successive calls to {@link #score()} will return the same |
| * result and will not invoke the wrapped Scorer's score() method, unless the |
| * current document has changed.<br> |
| * This class might be useful due to the changes done to the {@link Collector} |
| * interface, in which the score is not computed for a document by default, only |
| * if the collector requests it. Some collectors may need to use the score in |
| * several places, however all they have in hand is a {@link Scorer} object, and |
| * might end up computing the score of a document more than once. |
| */ |
| public class ScoreCachingWrappingScorer extends FilterScorer { |
| |
| private int curDoc = -1; |
| private float curScore; |
| |
| /** Creates a new instance by wrapping the given scorer. */ |
| public ScoreCachingWrappingScorer(Scorer scorer) { |
| super(scorer); |
| } |
| |
| @Override |
| public float score() throws IOException { |
| int doc = in.docID(); |
| if (doc != curDoc) { |
| curScore = in.score(); |
| curDoc = doc; |
| } |
| |
| return curScore; |
| } |
| |
| @Override |
| public Collection<ChildScorer> getChildren() { |
| return Collections.singleton(new ChildScorer(in, "CACHED")); |
| } |
| } |