. Net Lock (this), Lock (obj), Lock (& amp; quot; string & amp; quot;) console app demo, thread security

. Net Lock (this), Lock (obj), Lock (& quot; string & quot;) console app demo, thread security
Class Program
{
Static object obj = new object ();
Static int balance = 500;
Static void Main (string [] args)
{
// Todo with lock, Safe thread
// Thread t1 = new Thread (new ThreadStart (Credit ));
// T1.Start ();


// Thread t2 = new Thread () => Debit ());
// T2.Start ();


// Todo without lock, thread not safty
// Thread t1 = new Thread (new ThreadStart (CreditNoLock ));
// T1.Start ();


// Thread t2 = new Thread () => DebitNoLock ());
// T2.Start ();


// Todo new instance, lock (this --- context), Lock Failed
// Var account = new Account ();
// Thread t1 = new Thread (new ThreadStart (account. Credit ));
// T1.Start ();


// Var account2 = new Account ();
// Thread t2 = new Thread () => account2.Debit ());
// T2.Start ();


// Todo new instance, lock (obj-syncRoot), Lock Successed
Var account = new Account ();
Thread t1 = new Thread (new ThreadStart (account. CreditLockObj ));
T1.Start ();


Var account2 = new Account ();
Thread t2 = new Thread () => account2.DebitLockObj ());
T2.Start ();


// Todo conclusion !! Lock (this) is only valid for the current instance. lock (obj) is secure and lock ("string") is meaningless.




Console. ReadKey ();
}


Static void Credit ()
{
Lock (obj)
{
For (int I = 0; I <15; I ++)
{
Thread. Sleep (500 );
Balance + = 100;
Console. WriteLine ("After crediting, balance is {0}", balance );
}
}
}


Private static void Debit ()
{
Lock (obj)
{
For (int I = 0; I <15; I ++)
{
Thread. Sleep (500 );
Balance-= 100;
Console. WriteLine ("After debiting, balance is {0}", balance );
}
}
}




Static void CreditNoLock ()
{
For (int I = 0; I <15; I ++)
{
Thread. Sleep (1000 );
Balance + = 100;
Console. WriteLine ("After crediting, balance is {0}", balance );
}
}


Private static void DebitNoLock ()
{
For (int I = 0; I <15; I ++)
{
Thread. Sleep (1000 );
Balance-= 100;
Console. WriteLine ("After debiting, balance is {0}", balance );
}
}
}




Public class Account
{
Static int balance = 500;
Static object obj = new object ();
Public void Credit ()
{
Lock (this)
{
For (int I = 0; I <5; I ++)
{
Thread. Sleep (1000 );
Balance-= 100;
Console. WriteLine ("After debiting, balance is {0}", balance );
}
}
}


Public void Debit ()
{
Lock (this)
{
For (int I = 0; I <5; I ++)
{
Thread. Sleep (1000 );
Balance + = 100;
Console. WriteLine ("After debiting, balance is {0}", balance );
}
}
}




Public void CreditLockObj ()
{
Lock (obj)
{
For (int I = 0; I <5; I ++)
{


Thread. Sleep (1000 );
Balance-= 100;
Console. WriteLine ("After debiting, balance is {0}", balance );
}
}
}


Public void DebitLockObj ()
{
Lock (obj)
{
For (int I = 0; I <5; I ++)
{
Thread. Sleep (1000 );
Balance + = 100;
Console. WriteLine ("After debiting, balance is {0}", balance );
}
}
}

}