/// <summary>
/// An edge is relabeled by creating a new edge with the same properties, but new label.
/// Note that an edge is deleted and an edge is added.
/// </summary>
/// <param name="graph">the graph to add the new edge to</param>
/// <param name="oldEdge">the existing edge to "relabel"</param>
/// <param name="newId">the id of the new edge</param>
/// <param name="newLabel">the label of the new edge</param>
/// <returns>the newly created edge</returns>
public static IEdge RelabelEdge(this IEdge oldEdge, IGraph graph, object newId, string newLabel)
{
if (graph == null)
{
throw new ArgumentNullException(nameof(graph));
}
if (oldEdge == null)
{
throw new ArgumentNullException(nameof(oldEdge));
}
if (string.IsNullOrWhiteSpace(newLabel))
{
throw new ArgumentNullException(nameof(newLabel));
}
var outVertex = oldEdge.GetVertex(Direction.Out);
var inVertex = oldEdge.GetVertex(Direction.In);
var newEdge = graph.AddEdge(newId, outVertex, inVertex, newLabel);
oldEdge.CopyProperties(newEdge);
graph.RemoveEdge(oldEdge);
return(newEdge);
}