/*
* 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.jackrabbit.oak.plugins.index.lucene.util;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.List;
import org.apache.jackrabbit.oak.plugins.index.lucene.FieldNames;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexableField;
import org.apache.lucene.index.Term;
import org.apache.lucene.queries.mlt.MoreLikeThis;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TermQuery;
import org.apache.lucene.search.TopDocs;
/**
* Helper class for generating a {@link org.apache.lucene.queries.mlt.MoreLikeThisQuery} from the native query <code>String</code>
*/
public class MoreLikeThisHelper {
public static Query getMoreLikeThis(IndexReader reader, Analyzer analyzer, String mltQueryString) {
Query moreLikeThisQuery = null;
MoreLikeThis mlt = new MoreLikeThis(reader);
mlt.setAnalyzer(analyzer);
try {
String text = null;
String[] fields = {};
for (String param : mltQueryString.split("&")) {
String[] keyValuePair = param.split("=");
if (keyValuePair.length != 2 || keyValuePair[0] == null || keyValuePair[1] == null) {
throw new RuntimeException("Unparsable native Lucene MLT query: " + mltQueryString);
} else {
if ("stream.body".equals(keyValuePair[0])) {
text = keyValuePair[1];
} else if ("mlt.fl".equals(keyValuePair[0])) {
fields = keyValuePair[1].split(",");
} else if ("mlt.mindf".equals(keyValuePair[0])) {
mlt.setMinDocFreq(Integer.parseInt(keyValuePair[1]));
} else if ("mlt.mintf".equals(keyValuePair[0])) {
mlt.setMinTermFreq(Integer.parseInt(keyValuePair[1]));
} else if ("mlt.boost".equals(keyValuePair[0])) {
mlt.setBoost(Boolean.parseBoolean(keyValuePair[1]));
} else if ("mlt.qf".equals(keyValuePair[0])) {
mlt.setBoostFactor(Float.parseFloat(keyValuePair[1]));
} else if ("mlt.maxdf".equals(keyValuePair[0])) {
mlt.setMaxDocFreq(Integer.parseInt(keyValuePair[1]));
} else if ("mlt.maxdfp".equals(keyValuePair[0])) {
mlt.setMaxDocFreqPct(Integer.parseInt(keyValuePair[1]));
} else if ("mlt.maxntp".equals(keyValuePair[0])) {
mlt.setMaxNumTokensParsed(Integer.parseInt(keyValuePair[1]));
} else if ("mlt.maxqt".equals(keyValuePair[0])) {
mlt.setMaxQueryTerms(Integer.parseInt(keyValuePair[1]));
} else if ("mlt.maxwl".equals(keyValuePair[0])) {
mlt.setMaxWordLen(Integer.parseInt(keyValuePair[1]));
} else if ("mlt.minwl".equals(keyValuePair[0])) {
mlt.setMinWordLen(Integer.parseInt(keyValuePair[1]));
}
}
}
if (text != null) {
if (FieldNames.PATH.equals(fields[0])) {
IndexSearcher searcher = new IndexSearcher(reader);
TermQuery q = new TermQuery(new Term(FieldNames.PATH, text));
TopDocs top = searcher.search(q, 1);
if (top.totalHits == 0) {
mlt.setFieldNames(fields);
moreLikeThisQuery = mlt.like(new StringReader(text), mlt.getFieldNames()[0]);
} else{
ScoreDoc d = top.scoreDocs[0];
Document doc = reader.document(d.doc);
List<String> fieldNames = new ArrayList<String>();
for (IndexableField f : doc.getFields()) {
if (!FieldNames.PATH.equals(f.name())) {
fieldNames.add(f.name());
}
}
String[] docFields = fieldNames.toArray(new String[0]);
mlt.setFieldNames(docFields);
moreLikeThisQuery = mlt.like(d.doc);
}
} else {
mlt.setFieldNames(fields);
moreLikeThisQuery = mlt.like(new StringReader(text), mlt.getFieldNames()[0]);
}
}
return moreLikeThisQuery;
} catch (Exception e) {
throw new RuntimeException("could not handle MLT query " + mltQueryString);
}
}
}