Java Lucene NGramTokenizer

Question

I am trying tokenize strings into ngrams. Strangely in the documentation for the NGramTokenizer I do not see a method that will return the individual ngrams that were tokeni

Answer 1

package ngramalgoimpl;
import java.util.*;

public class ngr {

    public static List n_grams(int n, String str) {
        List n_grams = new ArrayList();
        String[] words = str.split(" ");
        for (int i = 0; i < words.length - n + 1; i++)
            n_grams.add(concatination(words, i, i+n));
        return n_grams;
    }
     /*stringBuilder is used to cancatinate mutable sequence of characters*/
    public static String concatination(String[] words, int start, int end) {
        StringBuilder sb = new StringBuilder();
        for (int i = start; i < end; i++)
            sb.append((i > start ? " " : "") + words[i]);
        return sb.toString();
    }

    public static void main(String[] args) {
        for (int n = 1; n <= 3; n++) {
            for (String ngram : n_grams(n, "This is my car."))
                System.out.println(ngram);
            System.out.println();
        }
    }
}