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Apache Solr (module: core)
/*
* 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.search;
import java.io.IOException;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.TreeSet;
import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.index.PostingsEnum;
import org.apache.lucene.index.Terms;
import org.apache.lucene.index.TermsEnum;
import org.apache.lucene.search.DocIdSetIterator;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.util.BytesRef;
import org.apache.lucene.util.SparseFixedBitSet;
import org.apache.solr.common.params.SolrParams;
import org.apache.solr.common.util.NamedList;
import org.apache.solr.handler.component.ResponseBuilder;
import org.apache.solr.request.SolrQueryRequest;
public class SignificantTermsQParserPlugin extends QParserPlugin {
public static final String NAME = "significantTerms";
@Override
public QParser createParser(String qstr, SolrParams localParams, SolrParams params, SolrQueryRequest req) {
return new SignifcantTermsQParser(qstr, localParams, params, req);
}
private static class SignifcantTermsQParser extends QParser {
public SignifcantTermsQParser(String qstr, SolrParams localParams, SolrParams params, SolrQueryRequest req) {
super(qstr, localParams, params, req);
}
@Override
public Query parse() throws SyntaxError {
String field = getParam("field");
int numTerms = Integer.parseInt(getParamWithDefault("numTerms", "20"));
float minDocs = Float.parseFloat(getParamWithDefault("minDocFreq", "5"));
float maxDocs = Float.parseFloat(getParamWithDefault("maxDocFreq", ".3"));
int minTermLength = Integer.parseInt(getParamWithDefault("minTermLength", "4"));
return new SignificantTermsQuery(field, numTerms, minDocs, maxDocs, minTermLength);
}
private String getParamWithDefault(String paramName, String defaultValue) {
String result = getParam(paramName);
return (result != null)? result: defaultValue;
}
}
private static class SignificantTermsQuery extends AnalyticsQuery {
private String field;
private int numTerms;
private float maxDocs;
private float minDocs;
private int minTermLength;
public SignificantTermsQuery(String field, int numTerms, float minDocs, float maxDocs, int minTermLength) {
this.field = field;
this.numTerms = numTerms;
this.minDocs = minDocs;
this.maxDocs = maxDocs;
this.minTermLength = minTermLength;
}
@Override
public DelegatingCollector getAnalyticsCollector(ResponseBuilder rb, IndexSearcher searcher) {
return new SignifcantTermsCollector(rb, searcher, field, numTerms, minDocs, maxDocs, minTermLength);
}
}
private static class SignifcantTermsCollector extends DelegatingCollector {
private String field;
private IndexSearcher searcher;
private ResponseBuilder rb;
private int numTerms;
private SparseFixedBitSet docs;
private int numDocs;
private float minDocs;
private float maxDocs;
private int count;
private int minTermLength;
private int highestCollected;
public SignifcantTermsCollector(ResponseBuilder rb, IndexSearcher searcher, String field, int numTerms, float minDocs, float maxDocs, int minTermLength) {
this.rb = rb;
this.searcher = searcher;
this.field = field;
this.numTerms = numTerms;
this.docs = new SparseFixedBitSet(searcher.getIndexReader().maxDoc());
this.numDocs = searcher.getIndexReader().numDocs();
this.minDocs = minDocs;
this.maxDocs = maxDocs;
this.minTermLength = minTermLength;
}
@Override
protected void doSetNextReader(LeafReaderContext context) throws IOException {
super.doSetNextReader(context);
}
@Override
public void collect(int doc) throws IOException {
super.collect(doc);
highestCollected = context.docBase + doc;
docs.set(highestCollected);
++count;
}
@Override
public void finish() throws IOException {
List outTerms = new ArrayList();
List outFreq = new ArrayList();
List outQueryFreq = new ArrayList();
List scores = new ArrayList();
NamedList allFreq = new NamedList();
NamedList allQueryFreq = new NamedList();
LinkedHashMap response = new LinkedHashMap<>();
rb.rsp.add("significantTerms", response);
response.put("numDocs", numDocs);
response.put("sterms", outTerms);
response.put("scores", scores);
response.put("docFreq", outFreq);
response.put("queryDocFreq", outQueryFreq);
//TODO: Use a priority queue
TreeSet topTerms = new TreeSet<>();
Terms terms = ((SolrIndexSearcher)searcher).getSlowAtomicReader().terms(field);
TermsEnum termsEnum = terms == null ? TermsEnum.EMPTY : terms.iterator();
BytesRef term;
PostingsEnum postingsEnum = null;
while ((term = termsEnum.next()) != null) {
int docFreq = termsEnum.docFreq();
if(minDocs < 1.0) {
if((float)docFreq/numDocs < minDocs) {
continue;
}
} else if(docFreq < minDocs) {
continue;
}
if(maxDocs < 1.0) {
if((float)docFreq/numDocs > maxDocs) {
continue;
}
} else if(docFreq > maxDocs) {
continue;
}
if(term.length < minTermLength) {
continue;
}
int tf = 0;
postingsEnum = termsEnum.postings(postingsEnum);
POSTINGS:
while (postingsEnum.nextDoc() != DocIdSetIterator.NO_MORE_DOCS) {
int docId = postingsEnum.docID();
if(docId > highestCollected) {
break POSTINGS;
}
if (docs.get(docId)) {
++tf;
}
}
if(tf == 0) {
continue;
}
float score = (float)Math.log(tf) * (float) (Math.log(((float)(numDocs + 1)) / (docFreq + 1)) + 1.0);
String t = term.utf8ToString();
allFreq.add(t, docFreq);
allQueryFreq.add(t, tf);
if (topTerms.size() < numTerms) {
topTerms.add(new TermWithScore(term.utf8ToString(), score));
} else {
if (topTerms.first().score < score) {
topTerms.pollFirst();
topTerms.add(new TermWithScore(term.utf8ToString(), score));
}
}
}
for (TermWithScore topTerm : topTerms) {
outTerms.add(topTerm.term);
scores.add(topTerm.score);
outFreq.add(allFreq.get(topTerm.term));
outQueryFreq.add(allQueryFreq.get(topTerm.term));
}
if (this.delegate instanceof DelegatingCollector) {
((DelegatingCollector) this.delegate).finish();
}
}
}
private static class TermWithScore implements Comparable{
public final String term;
public final double score;
public TermWithScore(String term, double score) {
this.term = term;
this.score = score;
}
@Override
public int hashCode() {
return term.hashCode();
}
@Override
public boolean equals(Object obj) {
if (obj == null) return false;
if (obj.getClass() != getClass()) return false;
TermWithScore other = (TermWithScore) obj;
return other.term.equals(this.term);
}
@Override
public int compareTo(TermWithScore o) {
int cmp = Double.compare(this.score, o.score);
if (cmp == 0) {
return this.term.compareTo(o.term);
} else {
return cmp;
}
}
}
}