/// <summary>
/// Add a new vertex from source to target
///
/// Complexity: 2 search + 1 insertion
/// </summary>
/// <param name="source">Source vertex</param>
/// <param name="target">Target vertex</param>
/// <returns>Created Edge</returns>
/// <exception cref="ArgumentNullException">source or target is null</exception>
/// <exception cref="Exception">source or target are not part of the graph</exception>
public virtual IEdge AddEdge(
IVertex source,
IVertex target
)
{
// look for the vertex in the list
if (!VertexOutEdges.ContainsKey(source))
{
throw new VertexNotFoundException("Could not find source vertex");
}
if (!VertexOutEdges.ContainsKey(target))
{
throw new VertexNotFoundException("Could not find target vertex");
}
// if parralel edges are not allowed check if already in the graph
if (!this.AllowParallelEdges)
{
if (ContainsEdge(source, target))
{
return(null);
}
}
// create edge
IEdge e = Provider.ProvideEdge(source, target);
VertexOutEdges[source].Add(e);
m_Edges.Add(e);
return(e);
}
/// <summary>
/// Used for serialization. Not for private use.
/// </summary>
/// <param name="e">edge to add.</param>
public virtual void AddEdge(IEdge e)
{
if (e == null)
{
throw new ArgumentNullException("vertex");
}
if (!VertexOutEdges.ContainsKey(e.Source))
{
throw new VertexNotFoundException("Could not find source vertex");
}
if (!VertexOutEdges.ContainsKey(e.Target))
{
throw new VertexNotFoundException("Could not find target vertex");
}
// if parralel edges are not allowed check if already in the graph
if (!this.AllowParallelEdges)
{
if (ContainsEdge(e.Source, e.Target))
{
throw new ArgumentException("graph does not allow duplicate edges");
}
}
// create edge
EdgeProvider.UpdateEdge(e);
VertexOutEdges[e.Source].Add(e);
}