public class TreeNode implements Position {
  
  private Object element;
  private TreeNode parent;
  private List children;

  public TreeNode() {
    element = null; 
    parent = null; 
    children = new NodeList(); 
  }

public TreeNode(Object elem) {
    element = elem; 
    parent = null; 
    children = new NodeList(); 
}


// c è una lista di TreeNode
public TreeNode(Object e, TreeNode p, List c) { 
    element = e;  
    parent = p; (p.getChildren()).insertLast(this);  
    children = c;
    int s=c.size();
    for(int i=0; i<s; i++) {
	TreeNode tmp = (TreeNode) c.remove(first());
        tmp.setParent(this);
	c.insertLast(tmp);
  } 
}


public Object element() { return element; }

public void setElement(Object e) { element = e; }

public TreeNode getParent() { return parent; }

public void setParent(TreeNode p) { parent = p; }

public List getChildren() { return children; }

// c è una lista di TreeNode
public void setChildren(List c) { children = c; }
}