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package org.apache.lucene.search;
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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import java.io.IOException;
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* A {@link Scorer} which wraps another scorer and caches the score of the
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* current document. Successive calls to {@link #score()} will return the same
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* result and will not invoke the wrapped Scorer's score() method, unless the
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* current document has changed.<br>
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* This class might be useful due to the changes done to the {@link Collector}
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* interface, in which the score is not computed for a document by default, only
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* if the collector requests it. Some collectors may need to use the score in
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* several places, however all they have in hand is a {@link Scorer} object, and
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* might end up computing the score of a document more than once.
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public class ScoreCachingWrappingScorer extends Scorer {
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private final Scorer scorer;
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private int curDoc = -1;
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private float curScore;
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/** Creates a new instance by wrapping the given scorer. */
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public ScoreCachingWrappingScorer(Scorer scorer) {
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super(scorer.getSimilarity(), scorer.weight);
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protected boolean score(Collector collector, int max, int firstDocID) throws IOException {
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return scorer.score(collector, max, firstDocID);
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public Similarity getSimilarity() {
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return scorer.getSimilarity();
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public float score() throws IOException {
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int doc = scorer.docID();
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curScore = scorer.score();
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return scorer.docID();
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public int nextDoc() throws IOException {
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return scorer.nextDoc();
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public void score(Collector collector) throws IOException {
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scorer.score(collector);
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public int advance(int target) throws IOException {
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return scorer.advance(target);