package org.apache.lucene.analysis.cz;
/**
* 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.analysis.Analyzer;
import org.apache.lucene.analysis.LowerCaseFilter;
import org.apache.lucene.analysis.StopFilter;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.WordlistLoader;
import org.apache.lucene.analysis.standard.StandardFilter;
import org.apache.lucene.analysis.standard.StandardTokenizer;
import java.io.*;
import java.util.Hashtable;
import java.util.HashSet;
import java.util.Set;
/**
* Analyzer for Czech language. Supports an external list of stopwords (words that
* will not be indexed at all).
* A default set of stopwords is used unless an alternative list is specified, the
* exclusion list is empty by default.
*
* @author Lukas Zapletal [lzap@root.cz]
*/
public final class CzechAnalyzer extends Analyzer {
/**
* List of typical stopwords.
*/
public final static String[] CZECH_STOP_WORDS = {
"a","s","k","o","i","u","v","z","dnes","cz","t\u00edmto","bude\u0161","budem",
"byli","jse\u0161","m\u016fj","sv\u00fdm","ta","tomto","tohle","tuto","tyto",
"jej","zda","pro\u010d","m\u00e1te","tato","kam","tohoto","kdo","kte\u0159\u00ed",
"mi","n\u00e1m","tom","tomuto","m\u00edt","nic","proto","kterou","byla",
"toho","proto\u017ee","asi","ho","na\u0161i","napi\u0161te","re","co\u017e","t\u00edm",
"tak\u017ee","sv\u00fdch","jej\u00ed","sv\u00fdmi","jste","aj","tu","tedy","teto",
"bylo","kde","ke","prav\u00e9","ji","nad","nejsou","\u010di","pod","t\u00e9ma",
"mezi","p\u0159es","ty","pak","v\u00e1m","ani","kdy\u017e","v\u0161ak","neg","jsem",
"tento","\u010dl\u00e1nku","\u010dl\u00e1nky","aby","jsme","p\u0159ed","pta","jejich",
"byl","je\u0161t\u011b","a\u017e","bez","tak\u00e9","pouze","prvn\u00ed","va\u0161e","kter\u00e1",
"n\u00e1s","nov\u00fd","tipy","pokud","m\u016f\u017ee","strana","jeho","sv\u00e9","jin\u00e9",
"zpr\u00e1vy","nov\u00e9","nen\u00ed","v\u00e1s","jen","podle","zde","u\u017e","b\u00fdt","v\u00edce",
"bude","ji\u017e","ne\u017e","kter\u00fd","by","kter\u00e9","co","nebo","ten","tak",
"m\u00e1","p\u0159i","od","po","jsou","jak","dal\u0161\u00ed","ale","si","se","ve",
"to","jako","za","zp\u011bt","ze","do","pro","je","na","atd","atp",
"jakmile","p\u0159i\u010dem\u017e","j\u00e1","on","ona","ono","oni","ony","my","vy",
"j\u00ed","ji","m\u011b","mne","jemu","tomu","t\u011bm","t\u011bmu","n\u011bmu","n\u011bmu\u017e",
"jeho\u017e","j\u00ed\u017e","jeliko\u017e","je\u017e","jako\u017e","na\u010de\u017e",
};
/**
* Contains the stopwords used with the StopFilter.
*/
private Set stoptable;
/**
* Builds an analyzer with the default stop words ({@link #CZECH_STOP_WORDS}).
*/
public CzechAnalyzer() {
stoptable = StopFilter.makeStopSet( CZECH_STOP_WORDS );
}
/**
* Builds an analyzer with the given stop words.
*/
public CzechAnalyzer( String[] stopwords ) {
stoptable = StopFilter.makeStopSet( stopwords );
}
public CzechAnalyzer( HashSet stopwords ) {
stoptable = stopwords;
}
/**
* Builds an analyzer with the given stop words.
*/
public CzechAnalyzer( File stopwords ) throws IOException {
stoptable = WordlistLoader.getWordSet( stopwords );
}
/**
* Loads stopwords hash from resource stream (file, database...).
* @param wordfile File containing the wordlist
* @param encoding Encoding used (win-1250, iso-8859-2, ...), null for default system encoding
*/
public void loadStopWords( InputStream wordfile, String encoding ) {
if ( wordfile == null ) {
stoptable = new HashSet();
return;
}
try {
// clear any previous table (if present)
stoptable = new HashSet();
InputStreamReader isr;
if (encoding == null)
isr = new InputStreamReader(wordfile);
else
isr = new InputStreamReader(wordfile, encoding);
LineNumberReader lnr = new LineNumberReader(isr);
String word;
while ( ( word = lnr.readLine() ) != null ) {
stoptable.add(word);
}
} catch ( IOException e ) {
stoptable = null;
}
}
/**
* Creates a TokenStream which tokenizes all the text in the provided Reader.
*
* @return A TokenStream build from a StandardTokenizer filtered with
* StandardFilter, LowerCaseFilter, and StopFilter
*/
public final TokenStream tokenStream( String fieldName, Reader reader ) {
TokenStream result = new StandardTokenizer( reader );
result = new StandardFilter( result );
result = new LowerCaseFilter( result );
result = new StopFilter( result, stoptable );
return result;
}
}