/**
  * Copyright (c): Uwe Schmidt, FH Wedel
  *
  * You may study, modify and distribute this source code
  * FOR NON-COMMERCIAL PURPOSES ONLY.
  * This copyright message has to remain unchanged.
  *
  * Note that this document is provided 'as is',
  * WITHOUT WARRANTY of any kind either expressed or implied.
  */

/**
  *
  * successive double elements are flitered out
  * 0 0 1 2 2 1 0 0 0 --> 0 1 2 1 0
  */

//--------------------

public
class Unique extends Sequence {
  private
  long last;

  private
  Sequence s;

  public
  Unique(Sequence s) {
    this.s      = s;
    this.last   = s.next();
  }

  public
  long next() {
    long res = last;

    while ( (last = s.next()) == res );

    return res;
  }
}

//--------------------