package org.apache.lucene.misc;
/**
* 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 org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.TermDocs;
import org.apache.lucene.index.TermEnum;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.util.PriorityQueue;
import java.util.Arrays;
import java.util.Comparator;
import java.io.File;
/**
* <code>HighFreqTerms</code> class extracts the top n most frequent terms
* (by document frequency ) from an existing Lucene index and reports their
* document frequency. If used with the -t flag it also reports their
* total tf (total number of occurences) in order of highest total tf
*/
public class HighFreqTerms {
// The top numTerms will be displayed
public static final int DEFAULTnumTerms = 100;
public static int numTerms = DEFAULTnumTerms;
public static void main(String[] args) throws Exception {
IndexReader reader = null;
FSDirectory dir = null;
String field = null;
boolean IncludeTermFreqs = false;
if (args.length == 0 || args.length > 4) {
usage();
System.exit(1);
}
if (args.length > 0) {
dir = FSDirectory.open(new File(args[0]));
}
for (int i = 1; i < args.length; i++) {
if (args[i].equals("-t")) {
IncludeTermFreqs = true;
}
else{
try {
numTerms = Integer.parseInt(args[i]);
} catch (NumberFormatException e) {
field=args[i];
}
}
}
reader = IndexReader.open(dir, true);
TermStats[] terms = getHighFreqTerms(reader, numTerms, field);
/*
* Insert logic so it will only lookup totaltf if right arg
* also change names as in flex
*/
if (!IncludeTermFreqs) {
//default HighFreqTerms behavior
for (int i = 0; i < terms.length; i++) {
System.out.printf("%s %,d \n",
terms[i].term, terms[i].docFreq);
}
} else {
TermStats[] termsWithTF = sortByTotalTermFreq(reader, terms);
for (int i = 0; i < termsWithTF.length; i++) {
System.out.printf("%s \t total_tf = %,d \t doc freq = %,d \n",
termsWithTF[i].term, termsWithTF[i].totalTermFreq, termsWithTF[i].docFreq);
}
}
reader.close();
}
private static void usage() {
System.out
.println("\n\n"
+ "java org.apache.lucene.misc.HighFreqTerms <index dir> [-t] [number_terms] [field]\n\t -t: include totalTermFreq\n\n");
}
/**
*
* @param reader
* @param numTerms
* @param field
* @return TermStats[] ordered by terms with highest docFreq first.
* @throws Exception
*/
public static TermStats[] getHighFreqTerms(IndexReader reader,
int numTerms, String field) throws Exception {
TermInfoWiTFQueue tiq = new TermInfoWiTFQueue(numTerms);
if (field != null) {
TermEnum terms = reader.terms(new Term(field));
if (terms != null && terms.term() != null) {
do {
if (!terms.term().field().equals(field)) {
break;
}
tiq.insertWithOverflow(new TermStats(terms.term(), terms.docFreq()));
} while (terms.next());
} else {
System.out.println("No terms for field \"" + field + "\"");
}
} else {
TermEnum terms = reader.terms();
while (terms.next()) {
tiq.insertWithOverflow(new TermStats(terms.term(), terms.docFreq()));
}
}
TermStats[] result = new TermStats[tiq.size()];
// we want highest first so we read the queue and populate the array
// starting at the end and work backwards
int count = tiq.size() - 1;
while (tiq.size() != 0) {
result[count] = tiq.pop();
count--;
}
return result;
}
/**
* Takes array of TermStats. For each term looks up the tf for each doc
* containing the term and stores the total in the output array of TermStats.
* Output array is sorted by highest total tf.
*
* @param reader
* @param terms
* TermStats[]
* @return TermStats[]
* @throws Exception
*/
public static TermStats[] sortByTotalTermFreq(IndexReader reader, TermStats[] terms) throws Exception {
TermStats[] ts = new TermStats[terms.length]; // array for sorting
long totalTF;
for (int i = 0; i < terms.length; i++) {
totalTF = getTotalTermFreq(reader, terms[i].term);
ts[i] = new TermStats( terms[i].term, terms[i].docFreq, totalTF);
}
Comparator<TermStats> c = new TotalTermFreqComparatorSortDescending();
Arrays.sort(ts, c);
return ts;
}
public static long getTotalTermFreq(IndexReader reader, Term term) throws Exception {
long totalTF = 0;
TermDocs td = reader.termDocs(term);
while (td.next()) {
totalTF += td.freq();
}
return totalTF;
}
}
final class TermStats {
public Term term;
public int docFreq;
public long totalTermFreq;
public TermStats(Term t, int df) {
this.term = t;
this.docFreq = df;
}
public TermStats(Term t, int df, long tf) {
this.term = t;
this.docFreq = df;
this.totalTermFreq = tf;
}
}
/**
* Priority queue for TermStats objects ordered by TermStats.docFreq
**/
final class TermInfoWiTFQueue extends PriorityQueue<TermStats> {
TermInfoWiTFQueue(int size) {
initialize(size);
}
@Override
protected boolean lessThan(TermStats termInfoA,
TermStats termInfoB) {
return termInfoA.docFreq < termInfoB.docFreq;
}
}
/**
* Comparator
*
* Reverse of normal Comparator. i.e. returns 1 if a.totalTermFreq is less than
* b.totalTermFreq So we can sort in descending order of totalTermFreq
*/
final class TotalTermFreqComparatorSortDescending implements Comparator<TermStats> {
public int compare(TermStats a, TermStats b) {
if (a.totalTermFreq < b.totalTermFreq) {
return 1;
} else if (a.totalTermFreq > b.totalTermFreq) {
return -1;
} else {
return 0;
}
}
}