package org.apache.lucene.misc;
/**
* Copyright 2006 The Apache Software Foundation
*
* Licensed 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.Term;
import org.apache.lucene.index.TermEnum;
import org.apache.lucene.index.TermDocs;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.search.Similarity;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
import java.io.File;
import java.io.IOException;
import java.util.Date;
/**
* Given a directory, a Similarity, and a list of fields, updates the
* fieldNorms in place for every document using the Similarity.lengthNorm.
*
* <p>
* NOTE: This only works if you do <b>not</b> use field/document boosts in your
* index.
* </p>
*
* @version $Id$
*/
public class LengthNormModifier {
/**
* Command Line Execution method.
*
* <pre>
* Usage: LengthNormModifier /path/index package.SimilarityClassName field1 field2 ...
* </pre>
*/
public static void main(String[] args) throws IOException {
if (args.length < 3) {
System.err.println("Usage: LengthNormModifier <index> <package.SimilarityClassName> <field1> [field2] ...");
System.exit(1);
}
Similarity s = null;
try {
Class simClass = Class.forName(args[1]);
s = (Similarity)simClass.newInstance();
} catch (Exception e) {
System.err.println("Couldn't instantiate similarity with empty constructor: " + args[1]);
e.printStackTrace(System.err);
}
File index = new File(args[0]);
Directory d = FSDirectory.getDirectory(index,false);
LengthNormModifier lnm = new LengthNormModifier(d, s);
for (int i = 2; i < args.length; i++) {
System.out.print("Updating field: " + args[i] + " " + (new Date()).toString() + " ... ");
lnm.reSetNorms(args[i]);
System.out.println(new Date().toString());
}
d.close();
}
private Directory dir;
private Similarity sim;
/**
* Constructor for code that wishes to use this class progaomatically.
*
* @param d The Directory to modify
* @param s The Similarity to use in <code>reSetNorms</code>
*/
public LengthNormModifier(Directory d, Similarity s) {
dir = d;
sim = s;
}
/**
* Resets the norms for the specified field.
*
* <p>
* Opens a new IndexReader on the Directory given to this instance,
* modifies the norms using the Similarity given to this instance,
* and closes the IndexReader.
* </p>
*
* @param field the field whose norms should be reset
*/
public void reSetNorms(String field) throws IOException {
String fieldName = field.intern();
int[] termCounts = new int[0];
IndexReader reader = null;
TermEnum termEnum = null;
TermDocs termDocs = null;
try {
reader = IndexReader.open(dir);
termCounts = new int[reader.maxDoc()];
try {
termEnum = reader.terms(new Term(field,""));
try {
termDocs = reader.termDocs();
do {
Term term = termEnum.term();
if (term != null && term.field().equals(fieldName)) {
termDocs.seek(termEnum.term());
while (termDocs.next()) {
termCounts[termDocs.doc()] += termDocs.freq();
}
}
} while (termEnum.next());
} finally {
if (null != termDocs) termDocs.close();
}
} finally {
if (null != termEnum) termEnum.close();
}
} finally {
if (null != reader) reader.close();
}
try {
reader = IndexReader.open(dir);
for (int d = 0; d < termCounts.length; d++) {
if (! reader.isDeleted(d)) {
byte norm = sim.encodeNorm(sim.lengthNorm(fieldName, termCounts[d]));
reader.setNorm(d, fieldName, norm);
}
}
} finally {
if (null != reader) reader.close();
}
}
}