/*
 * DirectedGraph.cs
 * Authors:
 * Copyright (c) 2007-2008 Cornell University

 This program is free software; you can redistribute it and/or
 modify it under the terms of the GNU General Public License
 as published by the Free Software Foundation; either version 2
 of the License, or (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/

using System;
using System.Collections.Generic;
using System.Text;

namespace ColonySim.Graphs
{
	/// <summary>
	/// Represents a directed graph, whose edges are directional.
	/// </summary>
	internal class DirectedGraph : Graph
	{
		#region Utility

		/// <summary>
		/// Creates an edge between the first node and the second node, from
		/// the first to the second.
		/// </summary>
		/// <param name="pA">The first node.</param>
		/// <param name="pB">The second node.</param>
		public override void CreateEdge(Node pA, Node pB)
		{
			// Create the edge between them, for each node
			pA.AddAdjacency(pB);
		}

		/// <summary>
		/// Removes an edge from the first node by removing the second node
		/// from its adjacency list.
		/// </summary>
		/// <param name="pA">The first node.</param>
		/// <param name="pB">The second node.</param>
		public override void DestroyEdge(Node pA, Node pB)
		{
			// Remove the adjacency from each of them
			pA.RemoveAdjacency(pB);
		}

		#endregion
	}
}