public static SingletonLoadBalancer GetLoadBalancer()
{
// Support multithreaded applications through
// 'Double checked locking' pattern which (once
// the instance exists) avoids locking each
// time the method is invoked
if (_instance == null)
{
lock (synlock)
{
if (_instance == null)
{
_instance = new SingletonLoadBalancer();
}
}
}
return(_instance);
}
static void Main(string[] args)
{
//Singleton
SingletonLoadBalancer b1 = SingletonLoadBalancer.GetLoadBalancer();
SingletonLoadBalancer b2 = SingletonLoadBalancer.GetLoadBalancer();
SingletonLoadBalancer b3 = SingletonLoadBalancer.GetLoadBalancer();
SingletonLoadBalancer b4 = SingletonLoadBalancer.GetLoadBalancer();
if (b1 == b2 && b2 == b3 && b3 == b4)
{
Console.WriteLine("Same instance\n");
}
//Load balance (e.g. 15th) server requests.
SingletonLoadBalancer balancer = SingletonLoadBalancer.GetLoadBalancer();
for (int i = 0; i < 15; i++)
{
string server = balancer.Server;
Console.WriteLine("Request to: " + server);
}
Console.WriteLine("\n");
//Facade
FacadeMortgage mortgage = new FacadeMortgage();
Customer customer = new Customer("Luis Vieira");
bool eligible = mortgage.IsEligible(customer, 30000);
Console.WriteLine("\n" + customer.Name + " has been " + (eligible ? "Approved" : "Rejected"));
Console.WriteLine("\n");
//Strategy
StrategySort studentRecords = new StrategySort();
studentRecords.Add("Samual");
studentRecords.Add("Jimmy");
studentRecords.Add("Sandra");
studentRecords.Add("Vivek");
studentRecords.Add("Anna");
studentRecords.SetSortStrategy(new QuickSort());
studentRecords.Sort();
studentRecords.SetSortStrategy(new ShellSort());
studentRecords.Sort();
studentRecords.SetSortStrategy(new MergeSort());
studentRecords.Sort();
Console.WriteLine("\n");
//Chain of Responsibility
ChainRepoApprover anna = new Director();
ChainRepoApprover paul = new VicePresident();
ChainRepoApprover bella = new President();
anna.SetSuccessor(paul);
paul.SetSuccessor(bella);
// Generate and process purchase requests
Purchase p = new Purchase(2034, 350.00, "Assets");
anna.ProcessRequest(p);
p = new Purchase(2035, 32590.10, "Project X");
anna.ProcessRequest(p);
p = new Purchase(2036, 42590.10, "Project Y");
anna.ProcessRequest(p);
p = new Purchase(2037, 122100.00, "Project Z");
anna.ProcessRequest(p);
Console.WriteLine("\n");
//Factory Method
//Note: constructors call Factory Method
FactoryDocument[] documents = new FactoryDocument[2];
documents[0] = new Resume();
documents[1] = new Report();
// Display document pages
foreach (FactoryDocument document in documents)
{
Console.WriteLine("\n" + document.GetType().Name + "--");
foreach (Page page in document.Pages)
{
Console.WriteLine(" " + page.GetType().Name);
}
}
Console.WriteLine("\n");
//Abstract Factory Method
AbstractFactoryProfile university = new University();
Community comm = new Community(university);
comm.RunActivities();
AbstractFactoryProfile hgSchool = new HighSchool();
comm = new Community(hgSchool);
comm.RunActivities();
AbstractFactoryProfile hospital = new Hospital();
comm = new Community(hospital);
comm.RunActivities();
Console.ReadKey();
}
