Graph Interface: Insert Edges

The Graph interface has an operation to insert edges:

/**
 * Insert a new edge.
 *
 * @param from Vertex position where the edge starts.
 * @param to   Vertex position where the edge ends.
 * @param e    Element to insert.
 * @return Edge position created to hold element.
 */
Edge<E> insert(Vertex<V> from, Vertex<V> to, E e);

When we add an edge, we specify the two vertices "from" and "to" and the data we may want to store in the edge.

Notice the insert method is overloaded: we've seen the insert method that created a vertex for us.

Like the method vertices, we have an edges method that returns an iterable over edges.

/**
 * Edges of graph.
 *
 * @return Iterable over all edges of the graph 
 *         (in no specific order).
 */
Iterable<Edge<E>> edges();