// We need methods that get the IDs of the set of dependent courses of a given course.
// These IDs will be used as input for constructing the graph relationships.
public int GetCourseIdFromName(string courseName, ThrowErrorOnMissing throwErrorOnMissing = ThrowErrorOnMissing.Yes)
{
if (!CourseAlreadyAdded(courseName)) // i.e. if Course is missing from Courses.
{
if (throwErrorOnMissing == ThrowErrorOnMissing.Yes)
{
throw new NullReferenceException(courseName + " has not been added to Courses!");
}
return(-1);
}
else
{
return(this[courseName].ID);
}
}
public string[] GetAdjacentCourseNamesFromCourseName(string courseName, ThrowErrorOnMissing throwErrorOnMissing = ThrowErrorOnMissing.Yes)
{
if (!CourseAlreadyAdded(courseName)) // i.e. if Course is missing from Courses.
{
if (throwErrorOnMissing == ThrowErrorOnMissing.Yes)
{
throw new NullReferenceException(courseName + " has not been added to Courses!");
}
return(new string[] {});
}
else
{
if (this[courseName].HasDependencies)
{
return(this[courseName].GetDependentCourseNames());
}
return(new string[] { });
}
}
public IEnumerable <int> GetAdjacentCourseIDsFromCourseId(int courseId, ThrowErrorOnMissing throwErrorOnMissing = ThrowErrorOnMissing.Yes)
{
if (!CourseIndexes.ContainsKey(courseId))
{
if (throwErrorOnMissing == ThrowErrorOnMissing.Yes)
{
throw new NullReferenceException(courseId + " has not been added to Course indexes!");
}
return(new List <int> {
});
}
else
{
var courseName = CourseIndexes[courseId];
var course = this[courseName];
if (course.HasDependencies)
{
return(this[courseName].GetDependentCourseIDs(this));
}
return(new List <int> {
});
}
}