/**
* Works on top of PositionalContainer method replaceElement(Position, Object) and
* InspectableContainer method contains().
*/
public void swapElements(Position a, Position b) throws InvalidAccessorException {
// Require that both of the swappees be in this container
if ((!this.contains(a)) || (!this.contains(b)))
throw new InvalidAccessorException("Positions do not belong to this container");
Object aelt = a.element();
replaceElement(a, b.element());
replaceElement(b, aelt);
}
public String stringfor(Position p) {
return "" + p.element();
}
/**
* @param pos Position for which string representation is desired
* @return verbose string representation of <code>pos</code>
*/
public static String stringfor(Position pos) {
if (pos == null) return "null position";
else return "Position with element " + pos.element();
}