/// <summary>
/// See base class description; visits predecessors
/// </summary>
/// <param name="vertex">The vertex to get the next vertices from</param>
/// <param name="wl">The work list to add the next vertices to</param>
/// <returns>True if it's possible to navigate further, false if not</returns>
public override bool GetNext(
object vertex,
Queue <EdgeItem> wl)
{
foreach (Edge edge in Graph.Predecessors(vertex))
{
EdgeItem item = new EdgeItem(edge, CurrentEdgeItem);
if (!CheckConstraints(edge.Source) ||
item == CurrentEdgeItem ||
wl.Contains(item) ||
HasTraversedInCurrentEdgeStack(edge))
{
continue;
}
wl.Enqueue(item);
}
return(true);
}
/// <summary>
/// See base class
/// </summary>
/// <param name="obj">See base class</param>
/// <returns>See base class</returns>
public override bool Equals(object obj)
{
EdgeItem other = obj as EdgeItem;
bool matchFound = false;
if (other != null)
{
if ((ParentEdgeItem != null &&
other.ParentEdgeItem != null))
{
matchFound = ParentEdgeItem.Edge == other.ParentEdgeItem.Edge;
}
else if ((ParentEdgeItem == null &&
other.ParentEdgeItem == null))
{
matchFound = true;
}
matchFound = matchFound && other.Edge == Edge;
}
return(matchFound);
}
/// <summary>
/// Initializes the edge item
/// </summary>
/// <param name="edge">The edge to associate with</param>
/// <param name="parentEdgeItem">The edge item's parent</param>
public EdgeItem(Edge edge, EdgeItem parentEdgeItem)
{
this.edge = edge;
this.parentEdgeItem = parentEdgeItem;
}