package clist;

public class CLList
{
  private ANode _clockwiseHead;
  private ANode _counterwiseHead;

  public CLList()
  {
    _clockwiseHead = NullNode.Singleton;
    _counterwiseHead = NullNode.Singleton;
  }

  public Object getClockwiseDat()
  {
    return _clockwiseHead.getDat(this);
  }

  public void setClockwiseDat(Object dat)
  {
    _clockwiseHead.setDat(dat, this);
  }

  public CLList getClockwiseTail()
  {
    return _clockwiseHead.getClockwiseTail(this);
  }

  public Object getCounterwiseDat()
  {
    return _counterwiseHead.getDat(this);
  }

  public void setCounterwiseDat(Object dat)
  {
    _counterwiseHead.setDat(dat, this);
  }

  public CLList getCounterwiseTail()
  {
    return _counterwiseHead.getCounterwiseTail(this);
  }
   
  public void insertClockwise(Object dat)
  {
    _clockwiseHead.insertClockwise(dat, this);
  }

  public void insertCounterwise(Object dat)
  {
    _counterwiseHead.insertCounterwise(dat, this);
  }

  public Object removeClockwise()
  {
    return _clockwiseHead.removeClockwise(this);
  }

  public Object removeCounterwise()
  {
    return _counterwiseHead.removeCounterwise(this);
  }

  public Object execClockwise(ICLVisitor algo, CLList start, Object input)
  {
    return _clockwiseHead.execClockwise(algo, start, input, this);
  }

  public Object execCounterwise(ICLVisitor algo, CLList start, Object input)
  {
    return _counterwiseHead.execCounterwise(algo, start, input, this);
  }

// Package access only:
 
  CLList(ANode counterwiseHead, ANode clockwiseHead)
  {
    _clockwiseHead = clockwiseHead;
    _clockwiseHead.setCounterwiseParent(this);

    _counterwiseHead = counterwiseHead;
    _counterwiseHead.setClockwiseParent(this);
  }

  ANode getClockwiseHead()
  {
    return _clockwiseHead;
  }

  void setClockwiseHead(ANode node)
  {
    _clockwiseHead = node;
    _clockwiseHead.setCounterwiseParent(this);
  }

  ANode getCounterwiseHead()
  {
    return _counterwiseHead;
  }

  void setCounterwiseHead(ANode node)
  {
    _counterwiseHead = node;
    _counterwiseHead.setClockwiseParent(this);
  }
}