org.apache.lucene.wordnet.Syns2Index Maven / Gradle / Ivy
package org.apache.lucene.wordnet;
/**
* 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.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
import java.util.TreeSet;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.index.IndexWriter;
/**
* Convert the prolog file wn_s.pl from the WordNet prolog download
* into a Lucene index suitable for looking up synonyms and performing query expansion ({@link SynExpand#expand SynExpand.expand(...)}).
*
* This has been tested with WordNet 2.0.
*
* The index has fields named "word" ({@link #F_WORD})
* and "syn" ({@link #F_SYN}).
*
* The source word (such as 'big') can be looked up in the
* "word" field, and if present there will be fields named "syn"
* for every synonym. What's tricky here is that there could be multiple
* fields with the same name, in the general case for words that have multiple synonyms.
* That's not a problem with Lucene, you just use {@link org.apache.lucene.document.Document#getValues}
*
*
* While the WordNet file distinguishes groups of synonyms with
* related meanings we don't do that here.
*
*
* This can take 4 minutes to execute and build an index on a "fast" system and the index takes up almost 3 MB.
*
* @see WordNet home page
* @see prologdb man page
* @see sample site that uses it
*/
public class Syns2Index
{
/**
*
*/
private static final PrintStream o = System.out;
/**
*
*/
private static final PrintStream err = System.err;
/**
*
*/
public static final String F_SYN = "syn";
/**
*
*/
public static final String F_WORD = "word";
/**
*
*/
private static final Analyzer ana = new StandardAnalyzer();
/**
* Takes arg of prolog file name and index directory.
*/
public static void main(String[] args)
throws Throwable
{
// get command line arguments
String prologFilename = null; // name of file "wn_s.pl"
String indexDir = null;
if (args.length == 2)
{
prologFilename = args[0];
indexDir = args[1];
}
else
{
usage();
System.exit(1);
}
// ensure that the prolog file is readable
if (! (new File(prologFilename)).canRead())
{
err.println("Error: cannot read Prolog file: " + prologFilename);
System.exit(1);
}
// exit if the target index directory already exists
if ((new File(indexDir)).isDirectory())
{
err.println("Error: index directory already exists: " + indexDir);
err.println("Please specify a name of a non-existent directory");
System.exit(1);
}
o.println("Opening Prolog file " + prologFilename);
final FileInputStream fis = new FileInputStream(prologFilename);
final BufferedReader br = new BufferedReader(new InputStreamReader(fis));
String line;
// maps a word to all the "groups" it's in
final Map word2Nums = new TreeMap();
// maps a group to all the words in it
final Map num2Words = new TreeMap();
// number of rejected words
int ndecent = 0;
// status output
int mod = 1;
int row = 1;
// parse prolog file
o.println( "[1/2] Parsing " + prologFilename);
while ((line = br.readLine()) != null)
{
// occasional progress
if ((++row) % mod == 0) // periodically print out line we read in
{
mod *= 2;
o.println("\t" + row + " " + line + " " + word2Nums.size()
+ " " + num2Words.size() + " ndecent=" + ndecent);
}
// syntax check
if (! line.startsWith("s("))
{
err.println("OUCH: " + line);
System.exit(1);
}
// parse line
line = line.substring(2);
int comma = line.indexOf(',');
String num = line.substring(0, comma);
int q1 = line.indexOf('\'');
line = line.substring(q1 + 1);
int q2 = line.indexOf('\'');
String word = line.substring(0, q2).toLowerCase();
// make sure is a normal word
if (! isDecent(word))
{
ndecent++;
continue; // don't store words w/ spaces
}
// 1/2: word2Nums map
// append to entry or add new one
List lis =(List) word2Nums.get(word);
if (lis == null)
{
lis = new LinkedList();
lis.add(num);
word2Nums.put(word, lis);
}
else
lis.add(num);
// 2/2: num2Words map
lis = (List) num2Words.get(num);
if (lis == null)
{
lis = new LinkedList();
lis.add(word);
num2Words.put(num, lis);
}
else
lis.add(word);
}
// close the streams
fis.close();
br.close();
// create the index
o.println( "[2/2] Building index to store synonyms, " +
" map sizes are " + word2Nums.size() + " and " + num2Words.size());
index(indexDir, word2Nums, num2Words);
}
/**
* Checks to see if a word contains only alphabetic characters by
* checking it one character at a time.
*
* @param s string to check
* @return true if the string is decent
*/
private static boolean isDecent(String s)
{
int len = s.length();
for (int i = 0; i < len; i++)
{
if (!Character.isLetter(s.charAt(i)))
{
return false;
}
}
return true;
}
/**
* Forms a Lucene index based on the 2 maps.
*
* @param indexDir the direcotry where the index should be created
* @param word2Nums
* @param num2Words
*/
private static void index(String indexDir, Map word2Nums, Map num2Words)
throws Throwable
{
int row = 0;
int mod = 1;
// override the specific index if it already exists
IndexWriter writer = new IndexWriter(indexDir, ana, true, IndexWriter.MaxFieldLength.LIMITED);
writer.setUseCompoundFile(true); // why?
Iterator i1 = word2Nums.keySet().iterator();
while (i1.hasNext()) // for each word
{
String g = (String) i1.next();
Document doc = new Document();
int n = index(word2Nums, num2Words, g, doc);
if (n > 0)
{
doc.add( new Field( F_WORD, g, Field.Store.YES, Field.Index.NOT_ANALYZED));
if ((++row % mod) == 0)
{
o.println("\trow=" + row + "/" + word2Nums.size() + " doc= " + doc);
mod *= 2;
}
writer.addDocument(doc);
} // else degenerate
}
o.println( "Optimizing..");
writer.optimize();
writer.close();
}
/**
* Given the 2 maps fills a document for 1 word.
*/
private static int index(Map word2Nums, Map num2Words, String g, Document doc)
throws Throwable
{
List keys = (List) word2Nums.get(g); // get list of key#'s
Iterator i2 = keys.iterator();
Set already = new TreeSet(); // keep them sorted
// pass 1: fill up 'already' with all words
while (i2.hasNext()) // for each key#
{
already.addAll((List) num2Words.get(i2.next())); // get list of words
}
int num = 0;
already.remove(g); // of course a word is it's own syn
Iterator it = already.iterator();
while (it.hasNext())
{
String cur = (String) it.next();
// don't store things like 'pit bull' -> 'american pit bull'
if (!isDecent(cur))
{
continue;
}
num++;
doc.add( new Field( F_SYN, cur, Field.Store.YES, Field.Index.NO));
}
return num;
}
/**
*
*/
private static void usage()
{
o.println("\n\n" +
"java org.apache.lucene.wordnet.Syns2Index \n\n");
}
}
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