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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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import java.io.Closeable;
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import org.apache.lucene.document.Document;
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import org.apache.lucene.document.FieldSelector;
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import org.apache.lucene.index.CorruptIndexException;
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import org.apache.lucene.index.Term;
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* The interface for search implementations.
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* Searchable is the abstract network protocol for searching. Implementations
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* provide search over a single index, over multiple indices, and over indices
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* Queries, filters and sort criteria are designed to be compact so that they
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* may be efficiently passed to a remote index, with only the top-scoring hits
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* being returned, rather than every matching hit.
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* <b>NOTE:</b> this interface is kept public for convenience. Since it is not
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* expected to be implemented directly, it may be changed unexpectedly between
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* @deprecated In 4.0 this interface is removed/absorbed
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public interface Searchable extends Closeable {
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* Lower-level search API.
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* {@link Collector#collect(int)} is called for every document. <br>
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* Collector-based access to remote indexes is discouraged.
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* Applications should only use this if they need <i>all</i> of the matching
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* documents. The high-level search API ({@link Searcher#search(Query,int)}) is
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* usually more efficient, as it skips non-high-scoring hits.
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* if non-null, used to permit documents to be collected.
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* @throws BooleanQuery.TooManyClauses
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void search(Weight weight, Filter filter, Collector collector) throws IOException;
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/** Frees resources associated with this Searcher.
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* Be careful not to call this method while you are still using objects
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* that reference this Searchable.
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void close() throws IOException;
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/** Expert: Returns the number of documents containing <code>term</code>.
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* @see org.apache.lucene.index.IndexReader#docFreq(Term)
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int docFreq(Term term) throws IOException;
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/** Expert: For each term in the terms array, calculates the number of
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* documents containing <code>term</code>. Returns an array with these
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* document frequencies. Used to minimize number of remote calls.
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int[] docFreqs(Term[] terms) throws IOException;
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/** Expert: Returns one greater than the largest possible document number.
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* @see org.apache.lucene.index.IndexReader#maxDoc()
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int maxDoc() throws IOException;
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/** Expert: Low-level search implementation. Finds the top <code>n</code>
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* hits for <code>query</code>, applying <code>filter</code> if non-null.
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* <p>Applications should usually call {@link Searcher#search(Query,int)} or
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* {@link Searcher#search(Query,Filter,int)} instead.
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* @throws BooleanQuery.TooManyClauses
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TopDocs search(Weight weight, Filter filter, int n) throws IOException;
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* Returns the stored fields of document <code>i</code>.
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* @see org.apache.lucene.index.IndexReader#document(int)
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* @throws CorruptIndexException if the index is corrupt
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* @throws IOException if there is a low-level IO error
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Document doc(int i) throws CorruptIndexException, IOException;
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* Get the {@link org.apache.lucene.document.Document} at the <code>n</code><sup>th</sup> position. The {@link org.apache.lucene.document.FieldSelector}
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* may be used to determine what {@link org.apache.lucene.document.Field}s to load and how they should be loaded.
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* <b>NOTE:</b> If the underlying Reader (more specifically, the underlying <code>FieldsReader</code>) is closed before the lazy {@link org.apache.lucene.document.Field} is
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* loaded an exception may be thrown. If you want the value of a lazy {@link org.apache.lucene.document.Field} to be available after closing you must
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* explicitly load it or fetch the Document again with a new loader.
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* @param n Get the document at the <code>n</code><sup>th</sup> position
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* @param fieldSelector The {@link org.apache.lucene.document.FieldSelector} to use to determine what Fields should be loaded on the Document. May be null, in which case all Fields will be loaded.
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* @return The stored fields of the {@link org.apache.lucene.document.Document} at the nth position
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* @throws CorruptIndexException if the index is corrupt
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* @throws IOException if there is a low-level IO error
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* @see org.apache.lucene.index.IndexReader#document(int, FieldSelector)
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* @see org.apache.lucene.document.Fieldable
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* @see org.apache.lucene.document.FieldSelector
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* @see org.apache.lucene.document.SetBasedFieldSelector
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* @see org.apache.lucene.document.LoadFirstFieldSelector
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Document doc(int n, FieldSelector fieldSelector) throws CorruptIndexException, IOException;
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/** Expert: called to re-write queries into primitive queries.
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* @throws BooleanQuery.TooManyClauses
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Query rewrite(Query query) throws IOException;
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/** Expert: low-level implementation method
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* Returns an Explanation that describes how <code>doc</code> scored against
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* <code>weight</code>.
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* <p>This is intended to be used in developing Similarity implementations,
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* and, for good performance, should not be displayed with every hit.
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* Computing an explanation is as expensive as executing the query over the
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* <p>Applications should call {@link Searcher#explain(Query, int)}.
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* @throws BooleanQuery.TooManyClauses
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Explanation explain(Weight weight, int doc) throws IOException;
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/** Expert: Low-level search implementation with arbitrary sorting. Finds
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* the top <code>n</code> hits for <code>query</code>, applying
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* <code>filter</code> if non-null, and sorting the hits by the criteria in
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* <p>Applications should usually call {@link
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* Searcher#search(Query,Filter,int,Sort)} instead.
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* @throws BooleanQuery.TooManyClauses
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TopFieldDocs search(Weight weight, Filter filter, int n, Sort sort)