71 lines
2.9 KiB
Java
71 lines
2.9 KiB
Java
/*
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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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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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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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*/
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package it.cavallium.dbengine.lucene.collector;
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import it.cavallium.dbengine.lucene.EmptyPriorityQueue;
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import it.cavallium.dbengine.lucene.FullDocs;
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import it.cavallium.dbengine.lucene.LLDocElement;
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import it.cavallium.dbengine.lucene.PqFullDocs;
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import it.cavallium.dbengine.lucene.PriorityQueue;
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import org.apache.lucene.search.Collector;
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import org.apache.lucene.search.TopDocs;
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import org.apache.lucene.search.TotalHits;
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/**
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* A base class for all collectors that return a {@link TopDocs} output. This collector allows easy
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* extension by providing a single constructor which accepts a {@link PriorityQueue} as well as
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* protected members for that priority queue and a counter of the number of total hits.<br>
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* Extending classes can override any of the methods to provide their own implementation, as well as
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* avoid the use of the priority queue entirely by passing null to {@link
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* #FullDocsCollector(PriorityQueue)}. In that case however, you might want to consider overriding
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* all methods, in order to avoid a NullPointerException.
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*/
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public abstract class FullDocsCollector<T extends LLDocElement> implements Collector, AutoCloseable {
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/**
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* The priority queue which holds the top documents. Note that different implementations of
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* PriorityQueue give different meaning to 'top documents'. HitQueue for example aggregates the
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* top scoring documents, while other PQ implementations may hold documents sorted by other
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* criteria.
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*/
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protected final PriorityQueue<T> pq;
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/** The total number of documents that the collector encountered. */
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protected int totalHits;
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/** Whether {@link #totalHits} is exact or a lower bound. */
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protected TotalHits.Relation totalHitsRelation = TotalHits.Relation.EQUAL_TO;
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protected FullDocsCollector(PriorityQueue<T> pq) {
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this.pq = pq;
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}
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/** The total number of documents that matched this query. */
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public int getTotalHits() {
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return totalHits;
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}
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/** Returns the top docs that were collected by this collector. */
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public FullDocs<T> fullDocs() {
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return new PqFullDocs<>(this.pq, new TotalHits(totalHits, totalHitsRelation));
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}
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@Override
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public void close() throws Exception {
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pq.close();
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}
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} |