/**

* An external node representation of a tree. Nodes of this type is used as a placeholder

* for further insertion. In case of insertion, the external node must be replaced by another

* internal nodes having two external nodes as children.

*

* @param <T> element type for the node

*/

public class ENode<T> extends Node<T> {

/**

* Creates an instance of an external node with its parent set to <tt>parent</tt>.

* Both children are <tt>null</tt>.

*

* @param parent the parent node

*/

public ENode(Node<T> parent) {

super(parent);

left = null;

right = null;

value = null;

}

/**

* Creates an instance of an external node with its parent set to <tt>null</tt>.

* Both children are <tt>null</tt>.

*/

public ENode() {

super(null);

left = null;

right = null;

value = null;

}

/**

* Check whether the position is an internal node.

* @return false

*/

@Override

public boolean isInternal() {

return false;

}

/**

* Check whether the position is an external node.

* @return true

*/

@Override

public boolean isExternal() {

return true;

}

}