NGramFeatureGenerator (Apache OpenNLP Tools 2.1.0 API)

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

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	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