package org.apache.solr.spelling;
import org.apache.lucene.search.spell.StringDistance;
/**
* 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.File;
import java.io.IOException;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.lucene.analysis.Token;
import org.apache.lucene.analysis.WhitespaceAnalyzer;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.spell.Dictionary;
import org.apache.lucene.search.spell.LevensteinDistance;
import org.apache.lucene.search.spell.SpellChecker;
import org.apache.lucene.search.spell.StringDistance;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.store.RAMDirectory;
import org.apache.solr.common.util.NamedList;
import org.apache.solr.core.SolrCore;
import org.apache.solr.schema.FieldType;
/**
* Abstract base class for all Lucene-based spell checking implementations.
*
* <p>
* Refer to <a href="http://wiki.apache.org/solr/SpellCheckComponent">SpellCheckComponent</a>
* for more details.
* </p>
*
* @since solr 1.3
*/
public abstract class AbstractLuceneSpellChecker extends SolrSpellChecker {
public static final Logger log = LoggerFactory.getLogger(AbstractLuceneSpellChecker.class);
public static final String SPELLCHECKER_ARG_NAME = "spellchecker";
public static final String LOCATION = "sourceLocation";
public static final String INDEX_DIR = "spellcheckIndexDir";
public static final String ACCURACY = "accuracy";
public static final String STRING_DISTANCE = "distanceMeasure";
public static final String FIELD_TYPE = "fieldType";
protected String field;
protected String fieldTypeName;
protected org.apache.lucene.search.spell.SpellChecker spellChecker;
protected String sourceLocation;
/*
* The Directory containing the Spell checking index
* */
protected Directory index;
protected Dictionary dictionary;
public static final int DEFAULT_SUGGESTION_COUNT = 5;
protected String indexDir;
protected float accuracy = 0.5f;
public static final String FIELD = "field";
public String init(NamedList config, SolrCore core) {
super.init(config, core);
indexDir = (String) config.get(INDEX_DIR);
String accuracy = (String) config.get(ACCURACY);
//If indexDir is relative then create index inside core.getDataDir()
if (indexDir != null) {
if (!new File(indexDir).isAbsolute()) {
indexDir = core.getDataDir() + File.separator + indexDir;
}
}
sourceLocation = (String) config.get(LOCATION);
field = (String) config.get(FIELD);
String strDistanceName = (String)config.get(STRING_DISTANCE);
StringDistance sd = null;
if (strDistanceName != null) {
sd = (StringDistance) core.getResourceLoader().newInstance(strDistanceName);
//TODO: Figure out how to configure options. Where's Spring when you need it? Or at least BeanUtils...
} else {
sd = new LevensteinDistance();
}
try {
initIndex();
spellChecker = new SpellChecker(index, sd);
} catch (IOException e) {
throw new RuntimeException(e);
}
if (accuracy != null) {
try {
this.accuracy = Float.parseFloat(accuracy);
spellChecker.setAccuracy(this.accuracy);
} catch (NumberFormatException e) {
throw new RuntimeException(
"Unparseable accuracy given for dictionary: " + name, e);
}
}
if (field != null && core.getSchema().getFieldTypeNoEx(field) != null) {
analyzer = core.getSchema().getFieldType(field).getQueryAnalyzer();
}
fieldTypeName = (String) config.get(FIELD_TYPE);
if (core.getSchema().getFieldTypes().containsKey(fieldTypeName)) {
FieldType fieldType = core.getSchema().getFieldTypes().get(fieldTypeName);
analyzer = fieldType.getQueryAnalyzer();
}
if (analyzer == null) {
log.info("Using WhitespaceAnalzyer for dictionary: " + name);
analyzer = new WhitespaceAnalyzer();
}
return name;
}
@SuppressWarnings("unchecked")
public SpellingResult getSuggestions(Collection<Token> tokens,
IndexReader reader, int count, boolean onlyMorePopular,
boolean extendedResults)
throws IOException {
SpellingResult result = new SpellingResult(tokens);
reader = determineReader(reader);
Term term = field != null ? new Term(field, "") : null;
for (Token token : tokens) {
String tokenText = new String(token.termBuffer(), 0, token.termLength());
String[] suggestions = spellChecker.suggestSimilar(tokenText, (int) Math.max(count, AbstractLuceneSpellChecker.DEFAULT_SUGGESTION_COUNT),
field != null ? reader : null, //workaround LUCENE-1295
field,
onlyMorePopular);
if (suggestions.length == 1 && suggestions[0].equals(tokenText)) {
//These are spelled the same, continue on
continue;
}
if (extendedResults == true && reader != null && field != null) {
term = term.createTerm(tokenText);
result.add(token, reader.docFreq(term));
int countLimit = Math.min(count, suggestions.length);
for (int i = 0; i < countLimit; i++) {
term = term.createTerm(suggestions[i]);
result.add(token, suggestions[i], reader.docFreq(term));
}
} else {
if (suggestions.length > 0) {
List<String> suggList = Arrays.asList(suggestions);
if (suggestions.length > count) {
suggList = suggList.subList(0, count);
}
result.add(token, suggList);
}
}
}
return result;
}
protected IndexReader determineReader(IndexReader reader) {
return reader;
}
public void reload() throws IOException {
spellChecker.setSpellIndex(index);
}
/**
* Initialize the {@link #index} variable based on the {@link #indexDir}. Does not actually create the spelling index.
*
* @throws IOException
*/
protected void initIndex() throws IOException {
if (indexDir != null) {
index = FSDirectory.getDirectory(indexDir);
} else {
index = new RAMDirectory();
}
}
/*
* @return the Accuracy used for the Spellchecker
* */
public float getAccuracy() {
return accuracy;
}
/*
* @return the Field used
*
* */
public String getField() {
return field;
}
/*
*
* @return the FieldType name.
* */
public String getFieldTypeName() {
return fieldTypeName;
}
/*
* @return the Index directory
* */
public String getIndexDir() {
return indexDir;
}
/*
* @return the location of the source
* */
public String getSourceLocation() {
return sourceLocation;
}
}