public void swap2(Node p1, Node p2){
	if (p1.getNextNode() == p2) {
            Node tmp1= p2.getNextNode();
	    Node tmp2= p1.getPreviousNode();
            
	    p1.setNextNode(tmp1);
	    p1.setPreviousNode(p2);
	    p2.setPreviousNode(tmp2);
	    tmp2.setNextNode(p2);
            p2.setNextNode(p1);
            tmp1.setPreviousNode(p1);
        }
        else if (p1.getPreviousNode() == p2) {
	    Node tmp1= p1.getNextNode();
	    Node tmp2= p2.getPreviousNode();
            
	    p2.setNextNode(tmp2);
	    p2.setPreviousNode(p1);
	    p1.setPreviousNode(tmp1);
	    tmp1.setNextNode(p1);
            p1.setNextNode(p2);
            tmp2.setPreviousNode(p2);
	}
	else { 
            Node tmp1= p1.getNextNode();
	    Node tmp2= p1.getPreviousNode();
	    
	    if (p1.getPreviousNode() != null)
		p1.getPreviousNode().setNextNode(p2);
	    if (p1.getNextNode() != null)
		p1.getNextNode().setPreviousNode(p2);

	    if (p2.getPreviousNode() != null)
		p2.getPreviousNode().setNextNode(p1);
	    if (p2.getNextNode() != null)
		p2.getNextNode().setPreviousNode(p1);

	    p1.setNextNode(p2.getNextNode());
	    p1.setPreviousNode(p2.getPreviousNode());
	    p2.setNextNode(tmp1);
	    p2.setPreviousNode(tmp2);

	}

	if (p1 == this.head)
	    this.head = p2;
	else if (p2 == this.head)
	    this.head = p1;
	
	if (p1 == this.tail)
	    this.tail = p2;
    	else if (p2 == this.tail)
	    this.tail = p1;
    }