Question

I am building a stock system which will be used over an office LAN with multiple users. I have a query about using the synchronized keyword to update the stock correctly. What I wish to do is allow multiple users to update the stock but of course only allow one user to update at one time. I have created a method as follows for the update of stock:

public static synchronized boolean UpdateXYZStock(Stock so){
 //update code
}

Is this the correct way to do this?

Thanks

S.

Answer 1

I would lock on an instance of the object, not the class. i.e. don’t lock a static method since you’re locking the class. Further to that you may want to lock on an underlying object e.g.

private final Object writeLock = new Object();

public boolean UpdateXYZStock(Stock so) {
   synchronized(writeLock) {
      ...
   }
}

so you can control the granularity of the locking more finely (I’m assuming this method is on a component within a server and thus serving multiple clients)