Reverse each k elements in LL

ReverseKLL.java

public void reverseKLL( Node head, int k ){
  Node prev;
  Node next;
  Node current = head;
  
  int count = 0;
  while( current != null ){
    Node boundaryNode = getBoundaryNode( current );
    while( boundaryNode != null && count < k ){
      next = current.getNext();
      if( count == 0 ){
        prev = boundaryNode;
      }
      current.setNext( prev );
      prev = current;
      current = next;
      count++;
    }
  }
}

public Node getBoundaryNode( Node node ){
    for( int i = 0; i< k; i ++){
      if( boundaryNode != null ){
        boundaryNode = boundaryNode.getNext();  
      }
    }
}