opennlp.tools.doccat

Class NGramFeatureGenerator

java.lang.Object

opennlp.tools.doccat.NGramFeatureGenerator

All Implemented Interfaces:

FeatureGenerator

public class NGramFeatureGenerator
extends Object
implements FeatureGenerator

Generates ngram features for a document. n-gram FeatureGenerator

Constructor Summary

Constructors

Constructor and Description
NGramFeatureGenerator() Default constructor for Bi grams
NGramFeatureGenerator(int minGram, int maxGram) Constructor for ngrams.

Method Summary

Modifier and Type	Method and Description
Collection<String>	extractFeatures(String[] text, Map<String,Object> extraInfo) Extract ngram features from given text fragments

Methods inherited from class java.lang.Object

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

Constructor Detail

NGramFeatureGenerator

public NGramFeatureGenerator(int minGram,
                             int maxGram)
                      throws InvalidFormatException

Constructor for ngrams.

Parameters:

minGram - minGram value - which means minimum words in ngram features

maxGram - maxGram value - which means maximum words in ngram features

Throws:

InvalidFormatException

NGramFeatureGenerator

public NGramFeatureGenerator()
                      throws InvalidFormatException

Default constructor for Bi grams

Throws:

InvalidFormatException

Method Detail

extractFeatures

public Collection<String> extractFeatures(String[] text,
                                          Map<String,Object> extraInfo)

Extract ngram features from given text fragments

Specified by:

extractFeatures in interface FeatureGenerator

Parameters:

text - the text fragments to extract features from

extraInfo - optional extra information

Returns:

a collection of n gram features