protected EdgeNGramTokenFilter(TokenStream input) 
{
    super(input);
    this.ngrams = new LinkedList();
}

 public EdgeNGramTokenFilter(TokenStream input,
    EdgeNGramTokenFilter.Side side,
    int minGram,
    int maxGram) 
{
    super(input);
    if (side == null) {
      throw new IllegalArgumentException("sideLabel must be either front or back");
    }
    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.side = side;
    this.ngrams = new LinkedList();
}

Creates EdgeNGramTokenFilter that can generate n-grams in the sizes of the given range

Parameters:

input - TokenStream holding the input to be tokenized

side - the Side from which to chop off an n-gram

minGram - the smallest n-gram to generate

maxGram - the largest n-gram to generate

 public EdgeNGramTokenFilter(TokenStream input,
    String sideLabel,
    int minGram,
    int maxGram) 
{
    this(input, Side.getSide(sideLabel), minGram, maxGram);
}

Creates EdgeNGramTokenFilter that can generate n-grams in the sizes of the given range

Parameters:

input - TokenStream holding the input to be tokenized

sideLabel - the name of the Side from which to chop off an n-gram

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.