edu.umn.cs.nlp
Class NGramDB

java.lang.Object
  edu.umn.cs.nlp.NGramDB

All Implemented Interfaces:

LanguageModel

public class NGramDB
extends Object
implements LanguageModel

NGram log probabilities distribution, stored as a Berkeley DB JE database.

Version:

$LastChangedDate$

Author:

Lane Schwartz

Field Summary

static String

ngramsDatabaseName

Constructor Summary

NGramDB(Scanner scanner, String dbDirectoryName, String dbEncoding)
Construct an object from ARPA backoff N-gram model file

NGramDB(String dbDirectoryName, String dbEncoding)
Construct an NGramLogProbabilities object by opening an existing Berkeley DB JE database which already contains the ngram data.

Method Summary

void	close() Close the underlying database.
double	get(String key) Get the language model probability for a given String.
int	getNGramCount(int order)
static void	main(String[] args)

Methods inherited from class java.lang.Object

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

Field Detail

ngramsDatabaseName

public static final String ngramsDatabaseName

See Also:

Constant Field Values

Constructor Detail

NGramDB

public NGramDB(Scanner scanner,
               String dbDirectoryName,
               String dbEncoding)

Construct an object from ARPA backoff N-gram model file

Parameters:

scanner - configured to read an ARPA backoff N-gram model file

dbDirectoryName - location where the database will be created

dbEncoding - text encoding to be used by the database

NGramDB

public NGramDB(String dbDirectoryName,
               String dbEncoding)
        throws FileNotFoundException

Construct an NGramLogProbabilities object by opening an existing Berkeley DB JE database which already contains the ngram data.

Parameters:

dbDirectoryName - location of the database

dbEncoding - text encoding used by the database

Throws:

FileNotFoundException

Method Detail

close

public void close()

Close the underlying database.

This method must be called in order to cleanly close the underlying database. If this method is not called, there is significant risk of corrupting the underlying database.

get

public double get(String key)

Description copied from interface: LanguageModel

Get the language model probability for a given String.

Specified by:

get in interface LanguageModel

Parameters:

key - string to look up

Returns:

the language model probability for the given String

getNGramCount

public int getNGramCount(int order)

main

public static void main(String[] args)