org.apache.lucene.analysis.nl

Class DutchAnalyzer

java.lang.Object

org.apache.lucene.analysis.Analyzer

org.apache.lucene.analysis.ReusableAnalyzerBase

org.apache.lucene.analysis.nl.DutchAnalyzer

All Implemented Interfaces:

Closeable

public final class DutchAnalyzer
extends ReusableAnalyzerBase

Analyzer for Dutch language.

Supports an external list of stopwords (words that will not be indexed at all), an external list of exclusions (word that will not be stemmed, but indexed) and an external list of word-stem pairs that overrule the algorithm (dictionary stemming). A default set of stopwords is used unless an alternative list is specified, but the exclusion list is empty by default.

You must specify the required Version compatibility when creating DutchAnalyzer:

• As of 3.6, DutchAnalyzer(Version, Set) and DutchAnalyzer(Version, Set, Set) also populate the default entries for the stem override dictionary
• As of 3.1, Snowball stemming is done with SnowballFilter, LowerCaseFilter is used prior to StopFilter, and Snowball stopwords are used by default.
• As of 2.9, StopFilter preserves position increments

NOTE: This class uses the same Version dependent settings as StandardAnalyzer.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.analysis.ReusableAnalyzerBase

ReusableAnalyzerBase.TokenStreamComponents

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT_STOPWORD_FILE File containing default Dutch stopwords.
static String[]	DUTCH_STOP_WORDS Deprecated. use getDefaultStopSet() instead

Constructor Summary

Constructors

Constructor and Description
DutchAnalyzer(Version matchVersion) Builds an analyzer with the default stop words (getDefaultStopSet()) and a few default entries for the stem exclusion table.
DutchAnalyzer(Version matchVersion, File stopwords) Deprecated. use DutchAnalyzer(Version, Set) instead
DutchAnalyzer(Version matchVersion, HashSet<?> stopwords) Deprecated. use DutchAnalyzer(Version, Set) instead
DutchAnalyzer(Version matchVersion, Set<?> stopwords)
DutchAnalyzer(Version matchVersion, Set<?> stopwords, Set<?> stemExclusionTable)
DutchAnalyzer(Version matchVersion, Set<?> stopwords, Set<?> stemExclusionTable, CharArrayMap<String> stemOverrideDict)
DutchAnalyzer(Version matchVersion, String... stopwords) Deprecated. use DutchAnalyzer(Version, Set) instead

Method Summary

Methods

Modifier and Type	Method and Description
protected ReusableAnalyzerBase.TokenStreamComponents	createComponents(String fieldName, Reader aReader) Returns a (possibly reused) TokenStream which tokenizes all the text in the provided Reader.
static Set<?>	getDefaultStopSet() Returns an unmodifiable instance of the default stop-words set.
void	setStemDictionary(File stemdictFile) Deprecated. This prevents reuse of TokenStreams. If you wish to use a custom stem dictionary, create your own Analyzer with StemmerOverrideFilter
void	setStemExclusionTable(File exclusionlist) Deprecated. use DutchAnalyzer(Version, Set, Set) instead
void	setStemExclusionTable(HashSet<?> exclusionlist) Deprecated. use DutchAnalyzer(Version, Set, Set) instead
void	setStemExclusionTable(String... exclusionlist) Deprecated. use DutchAnalyzer(Version, Set, Set) instead

Methods inherited from class org.apache.lucene.analysis.ReusableAnalyzerBase

initReader, reusableTokenStream, tokenStream

Methods inherited from class org.apache.lucene.analysis.Analyzer

close, getOffsetGap, getPositionIncrementGap, getPreviousTokenStream, setPreviousTokenStream

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DUTCH_STOP_WORDS

@Deprecated
public static final String[] DUTCH_STOP_WORDS

Deprecated. use getDefaultStopSet() instead

List of typical Dutch stopwords.

DEFAULT_STOPWORD_FILE

public static final String DEFAULT_STOPWORD_FILE

File containing default Dutch stopwords.

See Also:

Constant Field Values

Constructor Detail

DutchAnalyzer

public DutchAnalyzer(Version matchVersion)

Builds an analyzer with the default stop words (getDefaultStopSet()) and a few default entries for the stem exclusion table.

DutchAnalyzer

public DutchAnalyzer(Version matchVersion,
             Set<?> stopwords)

DutchAnalyzer

public DutchAnalyzer(Version matchVersion,
             Set<?> stopwords,
             Set<?> stemExclusionTable)

DutchAnalyzer

public DutchAnalyzer(Version matchVersion,
             Set<?> stopwords,
             Set<?> stemExclusionTable,
             CharArrayMap<String> stemOverrideDict)

DutchAnalyzer

@Deprecated
public DutchAnalyzer(Version matchVersion,
                        String... stopwords)

Deprecated. use DutchAnalyzer(Version, Set) instead

Builds an analyzer with the given stop words.

Parameters:

matchVersion -

stopwords -

DutchAnalyzer

@Deprecated
public DutchAnalyzer(Version matchVersion,
                        HashSet<?> stopwords)

Deprecated. use DutchAnalyzer(Version, Set) instead

Builds an analyzer with the given stop words.

Parameters:

stopwords -

DutchAnalyzer

@Deprecated
public DutchAnalyzer(Version matchVersion,
                        File stopwords)

Deprecated. use DutchAnalyzer(Version, Set) instead

Builds an analyzer with the given stop words.

Parameters:

stopwords -

Method Detail

getDefaultStopSet

public static Set<?> getDefaultStopSet()

Returns an unmodifiable instance of the default stop-words set.

Returns:

an unmodifiable instance of the default stop-words set.

setStemExclusionTable

@Deprecated
public void setStemExclusionTable(String... exclusionlist)

Deprecated. use DutchAnalyzer(Version, Set, Set) instead

Builds an exclusionlist from an array of Strings.

Parameters:

exclusionlist -

setStemExclusionTable

@Deprecated
public void setStemExclusionTable(HashSet<?> exclusionlist)

Deprecated. use DutchAnalyzer(Version, Set, Set) instead

Builds an exclusionlist from a Hashtable.

setStemExclusionTable

@Deprecated
public void setStemExclusionTable(File exclusionlist)

Deprecated. use DutchAnalyzer(Version, Set, Set) instead

Builds an exclusionlist from the words contained in the given file.

setStemDictionary

@Deprecated
public void setStemDictionary(File stemdictFile)

Deprecated. This prevents reuse of TokenStreams. If you wish to use a custom stem dictionary, create your own Analyzer with StemmerOverrideFilter

Reads a stemdictionary file , that overrules the stemming algorithm This is a textfile that contains per line word\tstem, i.e: two tab seperated words

createComponents

protected ReusableAnalyzerBase.TokenStreamComponents createComponents(String fieldName,
                                                          Reader aReader)

Returns a (possibly reused) TokenStream which tokenizes all the text in the provided Reader.

Specified by:

createComponents in class ReusableAnalyzerBase

Parameters:

fieldName - the name of the fields content passed to the ReusableAnalyzerBase.TokenStreamComponents sink as a reader

aReader - the reader passed to the Tokenizer constructor

Returns:

A TokenStream built from a StandardTokenizer filtered with StandardFilter, LowerCaseFilter, StopFilter, KeywordMarkerFilter if a stem exclusion set is provided, StemmerOverrideFilter, and SnowballFilter