public NGramTokenFilter(TokenStream input) 
{
    this(input, DEFAULT_MIN_NGRAM_SIZE, DEFAULT_MAX_NGRAM_SIZE);
}

Creates NGramTokenFilter with default min and max n-grams.

Parameters:

input - TokenStream holding the input to be tokenized

 public NGramTokenFilter(TokenStream input,
    int minGram,
    int maxGram) 
{
                                    
    super(input);
    if (minGram <  1) {
      throw new IllegalArgumentException("minGram must be greater than zero");
    }
    if (minGram  > maxGram) {
      throw new IllegalArgumentException("minGram must not be greater than maxGram");
    }
    this.minGram = minGram;
    this.maxGram = maxGram;
    this.ngrams = new LinkedList();
}

Creates NGramTokenFilter with given min and max n-grams.

Parameters:

input - TokenStream holding the input to be tokenized

minGram - the smallest n-gram to generate

maxGram - the largest n-gram to generate

 public final Token next() throws IOException 
{
    if (ngrams.size()  > 0) {
      return (Token) ngrams.removeFirst();
    }
    Token token = input.next();
    if (token == null) {
      return null;
    }
    ngram(token);
    if (ngrams.size()  > 0)
      return (Token) ngrams.removeFirst();
    else
      return null;
}

Returns the next token in the stream, or null at EOS.