static void Display <T>(HierarchyResult <T> hierarchy, Func <T, IEnumerable <T> > collectionIdentifier, Func <T, string> print) where T : class
{
if (hierarchy == null)
{
return;
}
if (hierarchy.HasError)
{
System.Console.ForegroundColor = ConsoleColor.Red;
System.Console.WriteLine("ERROR : {0}", hierarchy.Exception.Message);
System.Console.ResetColor();
}
else
{
Action <T, string> displayFunc = null;
displayFunc = (entity, tabFormat) =>
{
if (entity == null)
{
return;
}
if (string.IsNullOrEmpty(tabFormat))
{
System.Console.Write("\n{0}", print(entity));
}
else
{
System.Console.Write("\n{0}{1}", tabFormat, print(entity));
}
if (collectionIdentifier(entity).Any())
{
var collection = collectionIdentifier(entity);
tabFormat += "\t";
foreach (var teamMember in collection)
{
displayFunc(teamMember, tabFormat);
}
}
};
foreach (var executive in hierarchy.Executives)
{
displayFunc(executive.Value, "");
}
}
}
static void Display(HierarchyResult hierarchy)
{
if (hierarchy == null)
{
return;
}
if (hierarchy.HasError)
{
System.Console.ForegroundColor = ConsoleColor.Red;
System.Console.WriteLine("ERROR : {0}", hierarchy.Exception.Message);
System.Console.ResetColor();
}
else
{
Action <Employee, string> displayFunc = null;
displayFunc = (employee, tabFormat) =>
{
if (employee == null)
{
return;
}
if (string.IsNullOrEmpty(tabFormat))
{
System.Console.Write("\n{0}", employee.Name);
}
else
{
System.Console.Write("\n{0}{1}", tabFormat, employee.Name);
}
if (employee.Team != null && employee.Team.Any())
{
tabFormat += "\t";
foreach (var teamMember in employee.Team)
{
displayFunc(teamMember, tabFormat);
}
}
};
foreach (var executiveTeam in hierarchy.Executives)
{
displayFunc(executiveTeam.Value, "");
}
}
}
static HierarchyResult GetHierarchy(IEnumerable <Employee> employees)
{
var hierarchy = new HierarchyResult();
try
{
var employeeList = employees as List <Employee> ?? new List <Employee>(employees);
if (employeeList.Any() == false)
{
return(new HierarchyResult
{
Exception = new Exception("Please provide employees")
});
}
var employeesMappedById = employeeList.GroupBy(emp => emp.Id).ToDictionary(grp => grp.Key, grp => grp.Single());
//
// A dictionary to maintain who are the employees which we have already discovered
//
var visitedEmployees = new Dictionary <int, Employee>();
//
// Recursive function, to go through employees, and oragnize their teams
//
Action <IDictionary <int, Employee>, Employee, Employee> recursive = null;
recursive = (dict, employee, subOrdinate) =>
{
//
// If the structure already has an error, no need to continue
//
if (hierarchy.HasError)
{
return;
}
//
// If there's a subordinate to the passed employee add him to the "emp" team
//
if (subOrdinate != null)
{
employee.Team.Add(subOrdinate);
}
//
// If we have already processed the current employee, no need to continue further
//
if (visitedEmployees.ContainsKey(employee.Id))
{
return;
}
//
// If the employee has a manager, recursively call the function again, passing the employee as a "subordinate"
// of his manager (in this case the "manager")
//
if (employee.ManagerId.HasValue)
{
//
// If the manager is not a valid employee, set the error message
//
if (dict.ContainsKey(employee.ManagerId.Value))
{
recursive(dict, dict[employee.ManagerId.Value], employee);
}
else
{
hierarchy.Exception = new Exception(string.Format("Invalid employee with Id:[{0}]", employee.ManagerId));
}
}
else
{
if (hierarchy.Executives.ContainsKey(employee.Id) == false)
{
hierarchy.Executives.Add(employee.Id, employee);
}
}
visitedEmployees.Add(employee.Id, employee);
};
//
// Call the function to build the hierarchy
//
foreach (var employee in employeeList)
{
recursive(employeesMappedById, employee, null);
}
}
catch (InvalidOperationException exception)
{
hierarchy.Exception = new Exception("Employee id's are not unique");
}
catch (Exception exception)
{
hierarchy.Exception = new Exception("Cannot create the hierarchy");
}
return(hierarchy);
}
static HierarchyResult <T> GetHierarchy <T>(IEnumerable <T> collection,
Func <T, object> uniqueIdentifier,
Func <T, object> parentIdentifier,
Action <T, T> addFunc) where T : class
{
var hierarchy = new HierarchyResult <T>(uniqueIdentifier, parentIdentifier, addFunc);
try
{
var list = collection as List <T> ?? new List <T>(collection);
if (list.Any() == false)
{
hierarchy.Exception = new Exception("Please provide employees");
return(hierarchy);
}
var entitiesMappedByKey = list.GroupBy(uniqueIdentifier).ToDictionary(grp => grp.Key, grp => grp.Single());
//
// A dictionary to maintain who are the employees which we have already discovered
//
var visitedEntitiesMappedByKey = new Dictionary <object, T>();
//
// Recursive function, to go through employees, and oragnize their teams
//
Action <IDictionary <object, T>, T, T> recursive = null;
recursive = (dict, entity, childEntity) =>
{
//
// If the structure already has an error, no need to continue
//
if (hierarchy.HasError)
{
return;
}
//
// If there's a subordinate to the passed employee add him to the "emp" team
//
if (childEntity != null)
{
addFunc(entity, childEntity);
}
//
// If we have already processed the current employee, no need to continue further
//
if (visitedEntitiesMappedByKey.ContainsKey(uniqueIdentifier(entity)))
{
return;
}
//
// If the employee has a manager, recursively call the function again, passing the employee as a "subordinate"
// of his manager (in this case the "manager")
//
var parentKeyValue = parentIdentifier(entity);
if (parentKeyValue != null)
{
//
// If the manager is not a valid employee, set the error message
//
if (dict.ContainsKey(parentKeyValue))
{
recursive(dict, dict[parentKeyValue], entity);
}
else
{
hierarchy.Exception = new Exception(string.Format("Invalid employee with Id:[{0}]", parentKeyValue));
}
}
else
{
if (hierarchy.Executives.ContainsKey(uniqueIdentifier(entity)) == false)
{
hierarchy.Executives.Add(uniqueIdentifier(entity), entity);
}
}
visitedEntitiesMappedByKey.Add(uniqueIdentifier(entity), entity);
};
//
// Call the function to build the hierarchy
//
foreach (var employee in list)
{
recursive(entitiesMappedByKey, employee, null);
}
}
catch (InvalidOperationException exception)
{
hierarchy.Exception = new Exception(@"Provided unique identifier cannot identify entities distinctly");
}
catch (Exception exception)
{
hierarchy.Exception = new Exception("Cannot create the hierarchy");
}
return(hierarchy);
}