/**
* Adds an <tt>Edge</tt> into <tt>Path</tt>. This method ensures that the resulting <tt>Path</tt>
* is still simple. If not, an <tt>IllegalPathException</tt> is thrown.
*
* @params edge The Edge to be added to the Path
* @throws IllegalPathException Thrown when the <tt>vertexA</tt> property of the <tt>Edge</tt>
* being added is not the last <tt>Vertex</tt> in the path.
*/
public void addEdge(Edge edge) throws GraphException {
// Make sure the vertexB() is not in the Path already
this.validatePath(edge.getVertexB());
// The ancestor method will make sure that the last
// Object in the stack is the same as vertexA()
super.addEdge(edge);
}
