+++ /dev/null
-package org.apache.lucene.search.function;
-
-/**
- * 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.
- */
-
-/**
- * A query that scores each document as the value of the numeric input field.
- * <p>
- * The query matches all documents, and scores each document according to the numeric
- * value of that field.
- * <p>
- * It is assumed, and expected, that:
- * <ul>
- * <li>The field used here is indexed, and has exactly
- * one token in every scored document.</li>
- * <li>Best if this field is un_tokenized.</li>
- * <li>That token is parseable to the selected type.</li>
- * </ul>
- * <p>
- * Combining this query in a FunctionQuery allows much freedom in affecting document scores.
- * Note, that with this freedom comes responsibility: it is more than likely that the
- * default Lucene scoring is superior in quality to scoring modified as explained here.
- * However, in some cases, and certainly for research experiments, this capability may turn useful.
- * <p>
- * When constructing this query, select the appropriate type. That type should match the data stored in the
- * field. So in fact the "right" type should be selected before indexing. Type selection
- * has effect on the RAM usage:
- * <ul>
- * <li>{@link Type#BYTE} consumes 1 * maxDocs bytes.</li>
- * <li>{@link Type#SHORT} consumes 2 * maxDocs bytes.</li>
- * <li>{@link Type#INT} consumes 4 * maxDocs bytes.</li>
- * <li>{@link Type#FLOAT} consumes 8 * maxDocs bytes.</li>
- * </ul>
- * <p>
- * <b>Caching:</b>
- * Values for the numeric field are loaded once and cached in memory for further use with the same IndexReader.
- * To take advantage of this, it is extremely important to reuse index-readers or index-searchers,
- * otherwise, for instance if for each query a new index reader is opened, large penalties would be
- * paid for loading the field values into memory over and over again!
- *
- * @lucene.experimental
- */
-public class FieldScoreQuery extends ValueSourceQuery {
-
- /**
- * Type of score field, indicating how field values are interpreted/parsed.
- * <p>
- * The type selected at search search time should match the data stored in the field.
- * Different types have different RAM requirements:
- * <ul>
- * <li>{@link #BYTE} consumes 1 * maxDocs bytes.</li>
- * <li>{@link #SHORT} consumes 2 * maxDocs bytes.</li>
- * <li>{@link #INT} consumes 4 * maxDocs bytes.</li>
- * <li>{@link #FLOAT} consumes 8 * maxDocs bytes.</li>
- * </ul>
- */
- public static class Type {
-
- /** field values are interpreted as numeric byte values. */
- public static final Type BYTE = new Type("byte");
-
- /** field values are interpreted as numeric short values. */
- public static final Type SHORT = new Type("short");
-
- /** field values are interpreted as numeric int values. */
- public static final Type INT = new Type("int");
-
- /** field values are interpreted as numeric float values. */
- public static final Type FLOAT = new Type("float");
-
- private String typeName;
- private Type (String name) {
- this.typeName = name;
- }
- /*(non-Javadoc) @see java.lang.Object#toString() */
- @Override
- public String toString() {
- return getClass().getName()+"::"+typeName;
- }
- }
-
- /**
- * Create a FieldScoreQuery - a query that scores each document as the value of the numeric input field.
- * <p>
- * The <code>type</code> param tells how to parse the field string values into a numeric score value.
- * @param field the numeric field to be used.
- * @param type the type of the field: either
- * {@link Type#BYTE}, {@link Type#SHORT}, {@link Type#INT}, or {@link Type#FLOAT}.
- */
- public FieldScoreQuery(String field, Type type) {
- super(getValueSource(field,type));
- }
-
- // create the appropriate (cached) field value source.
- private static ValueSource getValueSource(String field, Type type) {
- if (type == Type.BYTE) {
- return new ByteFieldSource(field);
- }
- if (type == Type.SHORT) {
- return new ShortFieldSource(field);
- }
- if (type == Type.INT) {
- return new IntFieldSource(field);
- }
- if (type == Type.FLOAT) {
- return new FloatFieldSource(field);
- }
- throw new IllegalArgumentException(type+" is not a known Field Score Query Type!");
- }
-
-}
fnp / pylucene.git / blobdiff