/**
* 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.handler;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.spell.Dictionary;
import org.apache.lucene.search.spell.LuceneDictionary;
import org.apache.lucene.search.spell.SpellChecker;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.store.RAMDirectory;
import org.apache.solr.request.SolrParams;
import org.apache.solr.request.SolrQueryRequest;
import org.apache.solr.request.SolrQueryResponse;
import org.apache.solr.util.NamedList;
import org.apache.solr.core.SolrCore;
import org.apache.solr.core.SolrException;
import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.Arrays;
import java.util.logging.Logger;
/**
* Takes a string (e.g. a query string) as the value of the "q" parameter
* and looks up alternative spelling suggestions in the spellchecker.
* The spellchecker used by this handler is the Lucene contrib SpellChecker.
* @see <a href="http://wiki.apache.org/jakarta-lucene/SpellChecker">The Lucene Spellchecker documentation</a>
*
* @author Otis Gospodnetic
*/
public class SpellCheckerRequestHandler extends RequestHandlerBase {
private static Logger log = Logger.getLogger(SpellCheckerRequestHandler.class.getName());
private SpellChecker spellChecker;
/*
* From http://wiki.apache.org/jakarta-lucene/SpellChecker
* If reader and restrictToField are both not null:
* 1. The returned words are restricted only to the words presents in the field
* "restrictToField "of the Lucene Index "reader".
*
* 2. The list is also sorted with a second criterium: the popularity (the
* frequence) of the word in the user field.
*
* 3. If "onlyMorePopular" is true and the mispelled word exist in the user field,
* return only the words more frequent than this.
*
*/
private static IndexReader nullReader = null;
private String restrictToField = null;
private boolean onlyMorePopular = false;
private Directory spellcheckerIndexDir = new RAMDirectory();
private String dirDescription = "(ramdir)";
private String termSourceField;
private static final float DEFAULT_ACCURACY = 0.5f;
private static final int DEFAULT_NUM_SUGGESTIONS = 1;
public void init(NamedList args) {
super.init(args);
SolrParams p = SolrParams.toSolrParams(args);
termSourceField = p.get("termSourceField");
try {
String dir = p.get("spellcheckerIndexDir");
if (null != dir) {
File f = new File(dir);
if ( ! f.isAbsolute() ) {
f = new File(SolrCore.getSolrCore().getDataDir(), dir);
}
dirDescription = f.getAbsolutePath();
log.info("using spell directory: " + dirDescription);
spellcheckerIndexDir = FSDirectory.getDirectory(f);
} else {
log.info("using RAM based spell directory");
}
spellChecker = new SpellChecker(spellcheckerIndexDir);
} catch (IOException e) {
throw new RuntimeException("Cannot open SpellChecker index", e);
}
}
public void handleRequestBody(SolrQueryRequest req, SolrQueryResponse rsp)
throws Exception {
SolrParams p = req.getParams();
String words = p.get("q");
String cmd = p.get("cmd");
if (cmd != null) {
cmd = cmd.trim();
if (cmd.equals("rebuild")) {
rebuild(req);
rsp.add("cmdExecuted","rebuild");
} else if (cmd.equals("reopen")) {
reopen();
rsp.add("cmdExecuted","reopen");
} else {
throw new SolrException( SolrException.ErrorCode.BAD_REQUEST, "Unrecognized Command: " + cmd);
}
}
Float accuracy;
int numSug;
try {
accuracy = p.getFloat("accuracy", DEFAULT_ACCURACY);
spellChecker.setAccuracy(accuracy);
} catch (NumberFormatException e) {
throw new RuntimeException("Accuracy must be a valid positive float", e);
}
try {
numSug = p.getInt("suggestionCount", DEFAULT_NUM_SUGGESTIONS);
} catch (NumberFormatException e) {
throw new RuntimeException("Spelling suggestion count must be a valid positive integer", e);
}
if (null != words && !"".equals(words.trim())) {
String[] suggestions =
spellChecker.suggestSimilar(words, numSug,
nullReader, restrictToField,
onlyMorePopular);
rsp.add("suggestions", Arrays.asList(suggestions));
}
}
/** Rebuilds the SpellChecker index using values from the <code>termSourceField</code> from the
* index pointed to by the current {@link IndexSearcher}.
*/
private void rebuild(SolrQueryRequest req) throws IOException, SolrException {
if (null == termSourceField) {
throw new SolrException
(SolrException.ErrorCode.SERVER_ERROR, "can't rebuild spellchecker index without termSourceField configured");
}
IndexReader indexReader = req.getSearcher().getReader();
Dictionary dictionary = new LuceneDictionary(indexReader, termSourceField);
spellChecker.clearIndex();
spellChecker.indexDictionary(dictionary);
reopen();
}
/**
* Reopens the SpellChecker index directory.
* Useful if an external process is responsible for building
* the spell checker index.
*/
private void reopen() throws IOException {
spellChecker.setSpellIndex(spellcheckerIndexDir);
}
//////////////////////// SolrInfoMBeans methods //////////////////////
public String getVersion() {
return "$Revision: 542679 $";
}
public String getDescription() {
return "The SpellChecker Solr request handler for SpellChecker index: " + dirDescription;
}
public String getSourceId() {
return "$Id: SpellCheckerRequestHandler.java 542679 2007-05-29 22:28:21Z ryan $";
}
public String getSource() {
return "$URL: https://svn.apache.org/repos/asf/lucene/solr/branches/branch-1.2/src/java/org/apache/solr/handler/SpellCheckerRequestHandler.java $";
}
public URL[] getDocs() {
return null;
}
}