Package opennlp.tools.postag

Class POSTaggerME

java.lang.Object

opennlp.tools.postag.POSTaggerME

All Implemented Interfaces:

POSTagger

public class POSTaggerME
extends Object
implements POSTagger

A part-of-speech tagger that uses maximum entropy.

Tries to predict whether words are nouns, verbs, or any of 70 other POS tags depending on their surrounding context.

Field Summary

Fields

Modifier and Type	Field	Description
static int	DEFAULT_BEAM_SIZE

Constructor Summary

Constructors

Constructor	Description
POSTaggerME(String language)	Initializes a POSTaggerME by downloading a default model for a given language.
POSTaggerME(POSModel model)	Initializes a POSTaggerME with the provided model.

Method Summary

Modifier and Type	Method	Description
static Dictionary	buildNGramDictionary(ObjectStream<POSSample> samples, int cutoff)	Constructs a nGram dictionary from an ObjectStream of samples.
String[]	getAllPosTags()
String[]	getOrderedTags(List<String> words, List<String> tags, int index)
String[]	getOrderedTags(List<String> words, List<String> tags, int index, double[] tprobs)
static void	populatePOSDictionary(ObjectStream<POSSample> samples, MutableTagDictionary dict, int cutoff)	Populates a POSDictionary from an ObjectStream of samples.
double[]	probs()
void	probs(double[] probs)	Populates the specified array with the probabilities for each tag of the last tagged sentence.
String[][]	tag(int numTaggings, String[] sentence)	Returns at most the specified numTaggings for the specified sentence.
String[]	tag(String[] sentence)	Assigns the sentence of tokens pos tags.
String[]	tag(String[] sentence, Object[] additionalContext)	Assigns the sentence of tokens pos tags.
Sequence[]	topKSequences(String[] sentence)	Assigns the sentence the top-k sequences.
Sequence[]	topKSequences(String[] sentence, Object[] additionalContext)	Assigns the sentence the top-k sequences.
static POSModel	train(String languageCode, ObjectStream<POSSample> samples, TrainingParameters trainParams, POSTaggerFactory posFactory)

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_BEAM_SIZE

public static final int DEFAULT_BEAM_SIZE

See Also:

Constant Field Values

Constructor Detail

POSTaggerME

public POSTaggerME(String language)
            throws IOException

Initializes a POSTaggerME by downloading a default model for a given language.

Parameters:

language - An ISO conform language code.

Throws:

IOException - Thrown if the model could not be downloaded or saved.

POSTaggerME

public POSTaggerME(POSModel model)

Initializes a POSTaggerME with the provided model.

Parameters:

model - A valid POSModel.

Method Detail

getAllPosTags

public String[] getAllPosTags()

Returns:

Retrieves an array of all possible part-of-speech tags from the tagger.

tag

public String[] tag(String[] sentence)

Description copied from interface: POSTagger

Assigns the sentence of tokens pos tags.

Specified by:

tag in interface POSTagger

Parameters:

sentence - The sentence of tokens to be tagged.

Returns:

An array of pos tags for each token provided in sentence.

tag

public String[] tag(String[] sentence,
                    Object[] additionalContext)

Description copied from interface: POSTagger

Assigns the sentence of tokens pos tags.

Specified by:

tag in interface POSTagger

Parameters:

sentence - The sentence of tokens to be tagged.

additionalContext - The context to provide additional information with.

Returns:

An array of pos tags for each token provided in sentence.

tag

public String[][] tag(int numTaggings,
                      String[] sentence)

Returns at most the specified numTaggings for the specified sentence.

Parameters:

numTaggings - The number of tagging to be returned.

sentence - An array of tokens which make up a sentence.

Returns:

At most the specified number of taggings for the specified sentence.

topKSequences

public Sequence[] topKSequences(String[] sentence)

Description copied from interface: POSTagger

Assigns the sentence the top-k sequences.

Specified by:

topKSequences in interface POSTagger

Parameters:

sentence - The sentence of tokens to be tagged.

Returns:

An array of sequences for each token provided in sentence.

topKSequences

public Sequence[] topKSequences(String[] sentence,
                                Object[] additionalContext)

Description copied from interface: POSTagger

Assigns the sentence the top-k sequences.

Specified by:

topKSequences in interface POSTagger

Parameters:

sentence - The sentence of tokens to be tagged.

additionalContext - The context to provide additional information with.

Returns:

An array of sequences for each token provided in sentence.

probs

public void probs(double[] probs)

Populates the specified array with the probabilities for each tag of the last tagged sentence.

Parameters:

probs - An array to put the probabilities into.

probs

public double[] probs()

Returns:

An array with the probabilities for each tag of the last tagged sentence.

getOrderedTags

public String[] getOrderedTags(List<String> words,
                               List<String> tags,
                               int index)

getOrderedTags

public String[] getOrderedTags(List<String> words,
                               List<String> tags,
                               int index,
                               double[] tprobs)

train

public static POSModel train(String languageCode,
                             ObjectStream<POSSample> samples,
                             TrainingParameters trainParams,
                             POSTaggerFactory posFactory)
                      throws IOException

Throws:

IOException

buildNGramDictionary

public static Dictionary buildNGramDictionary(ObjectStream<POSSample> samples,
                                              int cutoff)
                                       throws IOException

Constructs a nGram dictionary from an ObjectStream of samples.

Parameters:

samples - The ObjectStream to process.

cutoff - A non-negative cut-off value.

Returns:

A valid Dictionary instance holding nGrams.

Throws:

IOException - Thrown if IO errors occurred during dictionary construction.

populatePOSDictionary

public static void populatePOSDictionary(ObjectStream<POSSample> samples,
                                         MutableTagDictionary dict,
                                         int cutoff)
                                  throws IOException

Populates a POSDictionary from an ObjectStream of samples.

Parameters:

samples - The ObjectStream to process.

dict - The MutableTagDictionary to use during population.

cutoff - A non-negative cut-off value.

Throws:

IOException - Thrown if IO errors occurred during dictionary construction.