Multithreaded linear lock

Sometimes we lock a piece of code may be based on the value of a variable, the same value does not allow two or more methods to run in parallel, I encountered in the work, there are 100 values, the same parameter values can not run in parallel.

There is a lock method recursive call will not deadlock, because it is necessary to lock the same variable. The answer, of course, is not deadlock.

Here is a test demo

classProgram {Private Static ObjectA =New Object(); Private Static Objectb =New Object(); Private Static Objectc =New Object(); Private StaticHashtable list = hashtable.synchronized (NewHashtable ()); Static voidMain (string[] args) {            //All I unequal threads will execute synchronously and return the result            NewThread (NewParameterizedthreadstart (Delegate(Objectobj) {Test (0, -); Console.WriteLine ("1"); })).            Start (); NewThread (NewParameterizedthreadstart (Delegate(Objectobj) {Test (1, -); Console.WriteLine ("1+"); })).            Start (); //all i==2 threads are executed sequentially            NewThread (NewParameterizedthreadstart (Delegate(Objectobj) {Test (2, -); Console.WriteLine ("2"); })).            Start (); NewThread (NewParameterizedthreadstart (Delegate(Objectobj) {Test (2, -); Console.WriteLine ("3"); })).            Start (); NewThread (NewParameterizedthreadstart (Delegate(Objectobj) {Test (2, -); Console.WriteLine ("4"); })).            Start (); NewThread (NewParameterizedthreadstart (Delegate(Objectobj) {Test (2, -); Console.WriteLine ("5"); })).            Start (); NewThread (NewParameterizedthreadstart (Delegate(Objectobj) {Test (2, -); Console.WriteLine ("6"); })).            Start (); //two times Lock the same variable does not deadlock            NewThread (NewParameterizedthreadstart (Delegate(Objectobj) {Test2 (3, -); Console.WriteLine ("7"); })).            Start ();        Console.readkey (); }        /// <summary>        ///blocking for I same thread is guaranteed not to parallel multiple/// </summary>        /// <param name= "i" ></param>        /// <param name= "J" ></param>         Public Static voidTest (intIintj) {if(!list. ContainsKey (i)) list.            ADD (i, DateTime.Now); Lock(List[i]) {thread.sleep (j); }        }                //multiple Lock the same variable tests if deadlock         Public Static voidTest2 (intIintJBOOLIsFirstRun =true)        {            if(!list. ContainsKey (i)) list.            ADD (i, DateTime.Now); Lock(List[i]) {thread.sleep (j); if(IsFirstRun) Test2 (i, J,false); }        }    }

The program output is as follows:

1+2137456

Multithreaded linear lock