import java.util.Vector;

/**
 * The class TNode implements the interface Position and is used in the
 * implementation of the interface Tree by means of a linked structure.
 *
 * @version    1.2    June 23, 2000
 * @author     Franck van Breugel
 * @see Position
 * @see Tree
 */
public class TNode implements Position 
{
    private Object element;       // element stored in this node
    private TNode parent;        // parent of this node
    private Vector children;      // children of this node
    
    /** Constructs an empty node. */
    public TNode() {}

    /**
     * Constructs a node with the specified element, parent and children.
     *
     * @param element The element stored in this node.
     * @param parent The parent of this node.
     * @param children The childen of this node.
     */
    public TNode(Object element, TNode parent, Vector children) 
    {
         this.element = element;
         this.parent = parent;
         this.children = children;
    }

    /**
     * Returns the element of this node.
     *
     * @return The element of this node.
     */
    public Object element() 
    {
        return element;
    }

    /**
     * Returns the parent of this node.
     *
     * @return The parent of this node.
     */
    public TNode getParent() 
    {
        return parent;
    }

    /**
     * Returns the children of this node.
     *
     * @return The children of this node.
     */
    public Vector getChildren()
    {
        return children;
    }


    /**
     * Set the element of this node to the specified element.
     *
     * @param element The element of this node.
     */
    public void setElement(Object element) 
    {
        this.element = element;
    }

    /**
     * Set the parent of this node to the specified node.
     *
     * @param parent The parent of this node.
     */
    public void setParent(TNode parent) 
    {
        this.parent = parent;
    }

    /**
     * Set the children of this node to the specified collection.
     *
     * @param children The children of this node.
     */
    public void setChildren(Vector children)
    {
        this.children = children;
    }

    /** 
     * Returns a string representation of the element stored in this node. 
     *
     * @return A string representation of the element stored in this node.
     */
    public String toString() 
    {
        return element.toString();
    }
}