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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 org.apache.solr.spelling.suggest.fst;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.search.suggest.Lookup;
import org.apache.lucene.search.suggest.analyzing.AnalyzingSuggester;
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;
/**
* Factory for {@link AnalyzingSuggester}
*
* @lucene.experimental
*/
public class AnalyzingLookupFactory extends LookupFactory {
/**
* If true
, exact suggestions are returned first, even if they are prefixes of other
* strings in the automaton (possibly with larger weights).
*/
public static final String EXACT_MATCH_FIRST = "exactMatchFirst";
/**
* If true
, then a separator between tokens is preserved. This means that suggestions
* are sensitive to tokenization (e.g. baseball is different from base ball).
*/
public static final String PRESERVE_SEP = "preserveSep";
/**
* When multiple suggestions collide to the same analyzed form, this is the limit of how many
* unique surface forms we keep.
*/
public static final String MAX_SURFACE_FORMS = "maxSurfaceFormsPerAnalyzedForm";
/**
* When building the FST ("index-time"), we add each path through the tokenstream graph as an
* individual entry. This places an upper-bound on how many expansions will be added for a single
* suggestion.
*/
public static final String MAX_EXPANSIONS = "maxGraphExpansions";
// confusingly: the queryAnalyzerFieldType parameter is something totally different, this
// is solr's "analysis" of the queries before they even reach the suggester (really makes
// little sense for suggest at all, only for spellcheck). So we pick different names.
/** The analyzer used at "query-time" and "build-time" to analyze suggestions. */
public static final String QUERY_ANALYZER = "suggestAnalyzerFieldType";
/** Whether position holes should appear in the automaton. */
public static final String PRESERVE_POSITION_INCREMENTS = "preservePositionIncrements";
/** File name for the automaton. */
private static final String FILENAME = "wfsta.bin";
@Override
public Lookup create(NamedList params, SolrCore core) {
// mandatory parameter
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();
// optional parameters
boolean exactMatchFirst =
params.get(EXACT_MATCH_FIRST) != null
? Boolean.valueOf(params.get(EXACT_MATCH_FIRST).toString())
: true;
boolean preserveSep =
params.get(PRESERVE_SEP) != null
? Boolean.valueOf(params.get(PRESERVE_SEP).toString())
: true;
int flags = 0;
if (exactMatchFirst) {
flags |= AnalyzingSuggester.EXACT_FIRST;
}
if (preserveSep) {
flags |= AnalyzingSuggester.PRESERVE_SEP;
}
int maxSurfaceFormsPerAnalyzedForm =
params.get(MAX_SURFACE_FORMS) != null
? Integer.parseInt(params.get(MAX_SURFACE_FORMS).toString())
: 256;
int maxGraphExpansions =
params.get(MAX_EXPANSIONS) != null
? Integer.parseInt(params.get(MAX_EXPANSIONS).toString())
: -1;
boolean preservePositionIncrements =
params.get(PRESERVE_POSITION_INCREMENTS) != null
? Boolean.valueOf(params.get(PRESERVE_POSITION_INCREMENTS).toString())
: false;
return new AnalyzingSuggester(
getTempDir(),
"suggester",
indexAnalyzer,
queryAnalyzer,
flags,
maxSurfaceFormsPerAnalyzedForm,
maxGraphExpansions,
preservePositionIncrements);
}
@Override
public String storeFileName() {
return FILENAME;
}
}