+++ /dev/null
-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.io.Serializable;
-
-import org.apache.lucene.index.IndexReader;
-
-/**
- * Expert: Calculate query weights and build query scorers.
- * <p>
- * The purpose of {@link Weight} is to ensure searching does not
- * modify a {@link Query}, so that a {@link Query} instance can be reused. <br>
- * {@link Searcher} dependent state of the query should reside in the
- * {@link Weight}. <br>
- * {@link IndexReader} dependent state should reside in the {@link Scorer}.
- * <p>
- * A <code>Weight</code> is used in the following way:
- * <ol>
- * <li>A <code>Weight</code> is constructed by a top-level query, given a
- * <code>Searcher</code> ({@link Query#createWeight(Searcher)}).
- * <li>The {@link #sumOfSquaredWeights()} method is called on the
- * <code>Weight</code> to compute the query normalization factor
- * {@link Similarity#queryNorm(float)} of the query clauses contained in the
- * query.
- * <li>The query normalization factor is passed to {@link #normalize(float)}. At
- * this point the weighting is complete.
- * <li>A <code>Scorer</code> is constructed by {@link #scorer(IndexReader,boolean,boolean)}.
- * </ol>
- *
- * @since 2.9
- */
-public abstract class Weight implements Serializable {
-
- /**
- * An explanation of the score computation for the named document.
- *
- * @param reader sub-reader containing the give doc
- * @param doc
- * @return an Explanation for the score
- * @throws IOException
- */
- public abstract Explanation explain(IndexReader reader, int doc) throws IOException;
-
- /** The query that this concerns. */
- public abstract Query getQuery();
-
- /** The weight for this query. */
- public abstract float getValue();
-
- /** Assigns the query normalization factor to this. */
- public abstract void normalize(float norm);
-
- /**
- * Returns a {@link Scorer} which scores documents in/out-of order according
- * to <code>scoreDocsInOrder</code>.
- * <p>
- * <b>NOTE:</b> even if <code>scoreDocsInOrder</code> is false, it is
- * recommended to check whether the returned <code>Scorer</code> indeed scores
- * documents out of order (i.e., call {@link #scoresDocsOutOfOrder()}), as
- * some <code>Scorer</code> implementations will always return documents
- * in-order.<br>
- * <b>NOTE:</b> null can be returned if no documents will be scored by this
- * query.
- *
- * @param reader
- * the {@link IndexReader} for which to return the {@link Scorer}.
- * @param scoreDocsInOrder
- * specifies whether in-order scoring of documents is required. Note
- * that if set to false (i.e., out-of-order scoring is required),
- * this method can return whatever scoring mode it supports, as every
- * in-order scorer is also an out-of-order one. However, an
- * out-of-order scorer may not support {@link Scorer#nextDoc()}
- * and/or {@link Scorer#advance(int)}, therefore it is recommended to
- * request an in-order scorer if use of these methods is required.
- * @param topScorer
- * if true, {@link Scorer#score(Collector)} will be called; if false,
- * {@link Scorer#nextDoc()} and/or {@link Scorer#advance(int)} will
- * be called.
- * @return a {@link Scorer} which scores documents in/out-of order.
- * @throws IOException
- */
- public abstract Scorer scorer(IndexReader reader, boolean scoreDocsInOrder,
- boolean topScorer) throws IOException;
-
- /** The sum of squared weights of contained query clauses. */
- public abstract float sumOfSquaredWeights() throws IOException;
-
- /**
- * Returns true iff this implementation scores docs only out of order. This
- * method is used in conjunction with {@link Collector}'s
- * {@link Collector#acceptsDocsOutOfOrder() acceptsDocsOutOfOrder} and
- * {@link #scorer(org.apache.lucene.index.IndexReader, boolean, boolean)} to
- * create a matching {@link Scorer} instance for a given {@link Collector}, or
- * vice versa.
- * <p>
- * <b>NOTE:</b> the default implementation returns <code>false</code>, i.e.
- * the <code>Scorer</code> scores documents in-order.
- */
- public boolean scoresDocsOutOfOrder() { return false; }
-
-}
fnp / pylucene.git / blobdiff