nGramAnalyzer.java

import java.util.List;
import java.util.ArrayList;

public class nGramAnalyzer {
	 public static List<String> ngrams(int n, String str) {
	        List<String> ngrams = new ArrayList<String>();
	        String[] words = str.split(" ");
	        for (int i = 0; i < words.length - n + 1; i++)
	            ngrams.add(concat(words, i, i+n));
	        return ngrams;
	    }

	    public static String concat(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 : ngrams(n, "برشلونة يفوز على ريال مدريد"))
	                System.out.println(ngram);
	            System.out.println();
	        }
	    }
	    
   
}