/// <summary>
/// Returns a collection of tags that has not changed int the messages consumed in this machine.
/// </summary>
/// <returns></returns>
protected TagsCollectionBase GetConstantTagsForCurrentMessages()
{
TagsCollectionBase constantTags = null;
foreach (var message in this.FinalMessages)
{
if (message is MicroPlannerMessageArc)
{
var tags = (message as MicroPlannerMessageArc).Arc.Tags;
if (tags == null)
{ // one of the tags collection is empty, intersection is also empty.
return(new TagsCollection());
}
else
{ // calculate intersection.
if (constantTags == null)
{ // first tags.
constantTags = tags;
}
else
{ // calculate intersection.
constantTags.Intersect(tags);
if (constantTags.Count == 0)
{ // no intersection.
return(constantTags);
}
}
}
}
}
return(constantTags);
}