io.redlink.lucene.search.suggest.FreeTextSuggesterFactory Maven / Gradle / Ivy

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Version of the Solr Free Text Suggestor that collate suggestions into the original search query and provides highlighting information about the parts of the suggested query that was appended/added by the highlighter.

There is a newer version: 2.1.1

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/*
 * 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 io.redlink.lucene.search.suggest;

import java.nio.charset.StandardCharsets;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.search.suggest.Lookup;
import org.apache.solr.common.util.NamedList;
import org.apache.solr.core.SolrCore;
import org.apache.solr.schema.FieldType;
import org.apache.solr.spelling.suggest.LookupFactory;

/**
 * LookupFactory implementation for {@link FreeTextSuggester}
 */
public class FreeTextSuggesterFactory extends LookupFactory {

    /**
     * The analyzer used at "query-time" and "build-time" to analyze
     * suggestions.
     */
    public static final String QUERY_ANALYZER = "suggestFreeTextAnalyzerFieldType";

    /**
     * The n-gram model to use in the underlying suggester; Default value is 2.
     */
    public static final String NGRAMS = "ngrams";

    /**
     * The separator to use in the underlying suggester;
     */
    public static final String SEPARATOR = "separator";

    /**
     * The penalty for scores if less tokens do match;
     */
    public static final String ALPHA = "alpha";
    /**
     * File name for the automaton.
     */
    private static final String FILENAME = "ftsta.bin";

    @Override
    public Lookup create(NamedList params, SolrCore core) {
        Object fieldTypeName = params.get(QUERY_ANALYZER);
        if (fieldTypeName == null) {
            throw new IllegalArgumentException("Error in configuration: " + QUERY_ANALYZER + " parameter is mandatory");
        }
        FieldType ft = core.getLatestSchema().getFieldTypeByName(fieldTypeName.toString());
        if (ft == null) {
            throw new IllegalArgumentException(
                    "Error in configuration: " + fieldTypeName.toString() + " is not defined in the schema");
        }

        Analyzer indexAnalyzer = ft.getIndexAnalyzer();
        Analyzer queryAnalyzer = ft.getQueryAnalyzer();

        int grams = (params.get(NGRAMS) != null) ? Integer.parseInt(params.get(NGRAMS).toString())
                : FreeTextSuggester.DEFAULT_GRAMS;

        byte separator = (params.get(SEPARATOR) != null)
                ? params.get(SEPARATOR).toString().getBytes(StandardCharsets.UTF_8)[0]
                : FreeTextSuggester.DEFAULT_SEPARATOR;

                
        double alpha = (params.get(ALPHA) != null) ? Double.parseDouble(params.get(ALPHA).toString())
                : FreeTextSuggester.DEFAULT_ALPHA;
        
        return new FreeTextSuggester(indexAnalyzer, queryAnalyzer, grams, separator, alpha);
    }

    @Override
    public String storeFileName() {
        return FILENAME;
    }

}