X-Git-Url: https://git.mdrn.pl/pylucene.git/blobdiff_plain/a2e61f0c04805cfcb8706176758d1283c7e3a55c..aaeed5504b982cf3545252ab528713250aa33eed:/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/Weight.java?ds=inline diff --git a/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/Weight.java b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/Weight.java new file mode 100644 index 0000000..77a56bf --- /dev/null +++ b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/Weight.java @@ -0,0 +1,118 @@ +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. + *
+ * The purpose of {@link Weight} is to ensure searching does not
+ * modify a {@link Query}, so that a {@link Query} instance can be reused.
+ * {@link Searcher} dependent state of the query should reside in the
+ * {@link Weight}.
+ * {@link IndexReader} dependent state should reside in the {@link Scorer}.
+ *
+ * A Weight
is used in the following way:
+ *
Weight
is constructed by a top-level query, given a
+ * Searcher
({@link Query#createWeight(Searcher)}).
+ * Weight
to compute the query normalization factor
+ * {@link Similarity#queryNorm(float)} of the query clauses contained in the
+ * query.
+ * Scorer
is constructed by {@link #scorer(IndexReader,boolean,boolean)}.
+ * scoreDocsInOrder
.
+ *
+ * NOTE: even if scoreDocsInOrder
is false, it is
+ * recommended to check whether the returned Scorer
indeed scores
+ * documents out of order (i.e., call {@link #scoresDocsOutOfOrder()}), as
+ * some Scorer
implementations will always return documents
+ * in-order.
+ * NOTE: 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.
+ *
+ * NOTE: the default implementation returns false
, i.e.
+ * the Scorer
scores documents in-order.
+ */
+ public boolean scoresDocsOutOfOrder() { return false; }
+
+}