| /* |
| * 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. |
| */ |
| package org.apache.solr.search.similarities; |
| |
| import org.apache.lucene.search.similarities.DFISimilarity; |
| import org.apache.lucene.search.similarities.Independence; |
| import org.apache.lucene.search.similarities.IndependenceChiSquared; |
| import org.apache.lucene.search.similarities.IndependenceSaturated; |
| import org.apache.lucene.search.similarities.IndependenceStandardized; |
| import org.apache.lucene.search.similarities.Similarity; |
| import org.apache.solr.common.params.SolrParams; |
| import org.apache.solr.schema.SimilarityFactory; |
| |
| /** |
| * Factory for {@link DFISimilarity} |
| * <p> |
| * You must specify the measure of divergence from independence ("independenceMeasure") |
| * <ul> |
| * <li>"Standardized": {@link IndependenceStandardized}</li> |
| * <li>"Saturated": {@link IndependenceSaturated}</li> |
| * <li>"ChiSquared": {@link IndependenceChiSquared}</li> |
| * </ul> |
| * Optional settings: |
| * <ul> |
| * <li>discountOverlaps (bool): Sets {@link org.apache.lucene.search.similarities.SimilarityBase#setDiscountOverlaps(boolean)}</li> |
| * </ul> |
| * |
| * @lucene.experimental |
| */ |
| public class DFISimilarityFactory extends SimilarityFactory { |
| |
| private boolean discountOverlaps; |
| private Independence independenceMeasure; |
| |
| @Override |
| public void init(SolrParams params) { |
| super.init(params); |
| discountOverlaps = params.getBool(ClassicSimilarityFactory.DISCOUNT_OVERLAPS, true); |
| independenceMeasure = parseIndependenceMeasure(params.get("independenceMeasure")); |
| } |
| |
| @Override |
| public Similarity getSimilarity() { |
| DFISimilarity sim = new DFISimilarity(independenceMeasure); |
| sim.setDiscountOverlaps(discountOverlaps); |
| return sim; |
| } |
| |
| private Independence parseIndependenceMeasure(String expr) { |
| if ("ChiSquared".equals(expr)) { |
| return new IndependenceChiSquared(); |
| } else if ("Standardized".equals(expr)) { |
| return new IndependenceStandardized(); |
| } else if ("Saturated".equals(expr)) { |
| return new IndependenceSaturated(); |
| } else { |
| throw new RuntimeException("Invalid independence measure: " + expr); |
| } |
| } |
| } |
| |