public void addFirst(StatementSequence statements){
  if (statements != null) {
    sequence.addAll(0,statements.sequence);
  }
}

public void addFirst ( StatementSequence statements ) { if ( statements != null ) { sequence . addAll ( 0 , statements . sequence ) ; } }
inserts a sequence of statements before the start of this sequence when the sequence object is not null , otherwise does nothing .
