static void Ex12()
{
//same Bank that
//can Transfer an amount from a source BankAccount
//to a target BankAccount.
//if multiple threads try to transfer from the same
//accounts, concurrency problems could arise....
ExampleLibrary.BankScenario.BankAccount ba1 = new ExampleLibrary.BankScenario.BankAccount()
{
Id = 1
};
ExampleLibrary.BankScenario.BankAccount ba2 = new ExampleLibrary.BankScenario.BankAccount()
{
Id = 2
};
ba1.Deposit(100);
ExampleLibrary.BankScenario.NotSynchronized.Bank bank = new ExampleLibrary.BankScenario.NotSynchronized.Bank();
for (int i = 0; i < 100; i++) //200 concurrent Threads running transfer
{
new Thread(() => {
bank.Transfer(ba1, ba2, 50);
Console.WriteLine($"{ba1.Id} == {ba1.Saldo}\t{ba2.Id} == {ba2.Saldo}");
}).Start();
new Thread(() => {
bank.Transfer(ba2, ba1, 50);
Console.WriteLine($"{ba1.Id} == {ba1.Saldo}\t{ba2.Id} == {ba2.Saldo}");
}).Start();
}
//we could see weird numbers popping up....
}
static void Ex11()
{
//in our scenario we have a Bank that
//can Transfer an amount from a source BankAccount
//to a target BankAccount.
//if we do not use multithreading,
//no problems will arise
ExampleLibrary.BankScenario.BankAccount ba1 = new ExampleLibrary.BankScenario.BankAccount()
{
Id = 1
};
ExampleLibrary.BankScenario.BankAccount ba2 = new ExampleLibrary.BankScenario.BankAccount()
{
Id = 2
};
ba1.Deposit(100);
ExampleLibrary.BankScenario.NotSynchronized.Bank bank = new ExampleLibrary.BankScenario.NotSynchronized.Bank();
for (int i = 0; i < 100; i++) //200 transfer
{
bank.Transfer(ba1, ba2, 50);
bank.Transfer(ba2, ba1, 50);
}
Console.WriteLine($"{ba1.Id} == {ba1.Saldo}\t{ba2.Id} == {ba2.Saldo}"); //ba1.Saldo == 100, ba2.Saldo == 0
}
static void Ex15()
{
//this Bank has an Event it's waiting for
//in order to proceed with the Transfer.
ExampleLibrary.BankScenario.BankAccount ba1 = new ExampleLibrary.BankScenario.BankAccount()
{
Id = 1
};
ExampleLibrary.BankScenario.BankAccount ba2 = new ExampleLibrary.BankScenario.BankAccount()
{
Id = 2
};
ba1.Deposit(100);
ExampleLibrary.BankScenario.EventWaitHandles.Bank bank = new ExampleLibrary.BankScenario.EventWaitHandles.Bank();
for (int i = 0; i < 100; i++) //200 concurrent Threads running transfer
{
new Thread(() => {
bank.Transfer(ba1, ba2, 50);
Console.WriteLine($"{ba1.Id} == {ba1.Saldo}\t{ba2.Id} == {ba2.Saldo}");
}).Start();
new Thread(() => {
bank.Transfer(ba2, ba1, 50);
Console.WriteLine($"{ba1.Id} == {ba1.Saldo}\t{ba2.Id} == {ba2.Saldo}");
}).Start();
}
}
static void Ex13()
{
//this Bank locks the bankAccounts it wants to use
//when Transfering an amount from a source BankAccount
//to a target BankAccount.
//if multiple threads try to transfer from the same
//accounts, deadlock problems could arise....
ExampleLibrary.BankScenario.BankAccount ba1 = new ExampleLibrary.BankScenario.BankAccount()
{
Id = 1
};
ExampleLibrary.BankScenario.BankAccount ba2 = new ExampleLibrary.BankScenario.BankAccount()
{
Id = 2
};
ba1.Deposit(100);
ExampleLibrary.BankScenario.Deadlocked.Bank bank = new ExampleLibrary.BankScenario.Deadlocked.Bank();
for (int i = 0; i < 100; i++) //200 concurrent Threads running transfer
{
new Thread(() => {
bank.Transfer(ba1, ba2, 50);
Console.WriteLine($"{ba1.Id} == {ba1.Saldo}\t{ba2.Id} == {ba2.Saldo}");
}).Start();
new Thread(() => {
bank.Transfer(ba2, ba1, 50);
Console.WriteLine($"{ba1.Id} == {ba1.Saldo}\t{ba2.Id} == {ba2.Saldo}");
}).Start();
}
//we could never get here....
}
static void Ex03()
{
//This example is equivalent to Ex15 of the Thread examples,
//but it's faster because it does not spawn 200 new Threads
//and it uses the ThreadPool instead.
ExampleLibrary.BankScenario.BankAccount ba1 = new ExampleLibrary.BankScenario.BankAccount()
{
Id = 1
};
ExampleLibrary.BankScenario.BankAccount ba2 = new ExampleLibrary.BankScenario.BankAccount()
{
Id = 2
};
ba1.Deposit(100);
ExampleLibrary.BankScenario.EventWaitHandles.Bank bank = new ExampleLibrary.BankScenario.EventWaitHandles.Bank();
for (int i = 0; i < 100; i++) //200 concurrent Threads running transfer
{
ThreadPool.QueueUserWorkItem(_ => {
bank.Transfer(ba1, ba2, 50);
Console.WriteLine($"{ba1.Id} == {ba1.Saldo}\t{ba2.Id} == {ba2.Saldo}");
});
ThreadPool.QueueUserWorkItem(_ => {
bank.Transfer(ba2, ba1, 50);
Console.WriteLine($"{ba1.Id} == {ba1.Saldo}\t{ba2.Id} == {ba2.Saldo}");
});
}
}
static void Ex17()
{
//In this scenario we want to wait for all Thread to finish
//before we continue.
//Another thing we could do is to create just one event
//and set it when a counter reaches 200.
//BUT we have to increase the same counter on 200 different threads,
//meaning that we have to do it in a thread safe manner.
AutoResetEvent doneEvent = new AutoResetEvent(false);
ExampleLibrary.BankScenario.BankAccount ba1 = new ExampleLibrary.BankScenario.BankAccount()
{
Id = 1
};
ExampleLibrary.BankScenario.BankAccount ba2 = new ExampleLibrary.BankScenario.BankAccount()
{
Id = 2
};
ba1.Deposit(100);
ExampleLibrary.BankScenario.EventWaitHandles.Bank bank = new ExampleLibrary.BankScenario.EventWaitHandles.Bank();
int counter = 0;
for (int i = 0; i < 100; i++) //200 concurrent Threads running transfer
{
new Thread(() => {
bank.Transfer(ba1, ba2, 50);
Interlocked.Increment(ref counter);
Console.WriteLine($"{ba1.Id} == {ba1.Saldo}\t{ba2.Id} == {ba2.Saldo}");
if (counter == 200)
{
doneEvent.Set();
}
}).Start();
new Thread(() => {
bank.Transfer(ba2, ba1, 50);
Interlocked.Increment(ref counter);
Console.WriteLine($"{ba1.Id} == {ba1.Saldo}\t{ba2.Id} == {ba2.Saldo}");
if (counter == 200)
{
doneEvent.Set();
}
}).Start();
}
doneEvent.WaitOne();
Console.WriteLine("DONE!!");
}
static void Ex14()
{
//this Bank tries to lock the bankAccounts it wants to use
//for 10 milliseconds, after which it stops trying.
//that's why this transfer could fail.
//if multiple threads try to transfer from the same
//accounts, the transfer could fail,
//so we can decide if we want to keep trying,
//or stop, or who knows what
ExampleLibrary.BankScenario.BankAccount ba1 = new ExampleLibrary.BankScenario.BankAccount()
{
Id = 1
};
ExampleLibrary.BankScenario.BankAccount ba2 = new ExampleLibrary.BankScenario.BankAccount()
{
Id = 2
};
ba1.Deposit(100);
ExampleLibrary.BankScenario.Timeout.Bank bank = new ExampleLibrary.BankScenario.Timeout.Bank();
for (int i = 0; i < 100; i++) //200 concurrent Threads running transfer
{
new Thread(() => {
while (!bank.Transfer(ba1, ba2, 50)) //it could timeout
{
Console.Write(".");
} //keep trying until we get it
Console.WriteLine($"{ba1.Id} == {ba1.Saldo}\t{ba2.Id} == {ba2.Saldo}");
}).Start();
new Thread(() => {
while (!bank.Transfer(ba2, ba1, 50)) //it could timeout
{
Console.Write(".");
} //keep trying until we get it
Console.WriteLine($"{ba1.Id} == {ba1.Saldo}\t{ba2.Id} == {ba2.Saldo}");
}).Start();
}
}
static void Ex16()
{
//In this scenario we want to wait for all Thread to finish
//before we continue.
//We could create 200 AutoResetEvents, put them in an Array,
//signal each one of them from a Thread
//and use EventWaitHandle.WaitAll,
//but they would be too many.
AutoResetEvent[] events = Enumerable.Repeat(new AutoResetEvent(false), 200).ToArray();
ExampleLibrary.BankScenario.BankAccount ba1 = new ExampleLibrary.BankScenario.BankAccount()
{
Id = 1
};
ExampleLibrary.BankScenario.BankAccount ba2 = new ExampleLibrary.BankScenario.BankAccount()
{
Id = 2
};
ba1.Deposit(100);
ExampleLibrary.BankScenario.EventWaitHandles.Bank bank = new ExampleLibrary.BankScenario.EventWaitHandles.Bank();
for (int i = 0; i < 100; i++) //200 concurrent Threads running transfer
{
new Thread(() => {
bank.Transfer(ba1, ba2, 50);
events[i].Set();
Console.WriteLine($"{ba1.Id} == {ba1.Saldo}\t{ba2.Id} == {ba2.Saldo}");
}).Start();
new Thread(() => {
bank.Transfer(ba2, ba1, 50);
events[i + 100].Set();
Console.WriteLine($"{ba1.Id} == {ba1.Saldo}\t{ba2.Id} == {ba2.Saldo}");
}).Start();
}
//boom!
WaitHandle.WaitAll(events);
Console.WriteLine("DONE!!");
}
static void Ex18()
{
//In this scenario we want to wait for all Thread to finish
//before we continue.
//Another thing we could do is to use a CountdownEvent.
CountdownEvent doneEvent = new CountdownEvent(200);
ExampleLibrary.BankScenario.BankAccount ba1 = new ExampleLibrary.BankScenario.BankAccount()
{
Id = 1
};
ExampleLibrary.BankScenario.BankAccount ba2 = new ExampleLibrary.BankScenario.BankAccount()
{
Id = 2
};
ba1.Deposit(100);
ExampleLibrary.BankScenario.EventWaitHandles.Bank bank = new ExampleLibrary.BankScenario.EventWaitHandles.Bank();
for (int i = 0; i < 100; i++) //200 concurrent Threads running transfer
{
new Thread(() => {
bank.Transfer(ba1, ba2, 50);
Console.WriteLine($"{ba1.Id} == {ba1.Saldo}\t{ba2.Id} == {ba2.Saldo}");
doneEvent.Signal();
}).Start();
new Thread(() => {
bank.Transfer(ba2, ba1, 50);
Console.WriteLine($"{ba1.Id} == {ba1.Saldo}\t{ba2.Id} == {ba2.Saldo}");
doneEvent.Signal();
}).Start();
}
doneEvent.Wait(); //waiting for it to reach 0
Console.WriteLine("DONE!!");
}
