Simple Question: Getting Current Thread

Question

hi. i'm confused about the currentThread() method. it's a method of the Thread class, but if you have to call it from a Thread, then what's the point?
say in my program i want to find out what the currently executing thread is. how can i call a method of the Thread class when i don't have a Thread object? if i knew which thread were running, i wouldn't need to call the function. you know what i mean?
so i guess there must be a way to get ahold of whatever thread you're in at any point in your code, right? what if i want to get the currently executing thread in my GUI- like, everytime i push a certain button, i want to put the thread handling that button to sleep or something. can it be done? if so, how?
thnx in advance
~spoongirl

Answer 1

I'm not familiar with the static keyword in C, but when it's used for a method in Java, it means the method is a class method instead of an instance method.
Consider the Math class, with a whole bunch of static methods. For example, the cos(double a) method. The cosine of a 45 degree angle will always be the same, so there's no need to have an instance of the Math class in order to use the method; regardless of what you would want to do with that instance, the cos() method would have to return the same value if you pass it the value 45, so it might as well be accessible regardless of whether or not there's an instance of the class.
The same is true for variables. Again in the Math class, there's the constant PI. The value of PI is always going to be 3.14etc., so there wouldn't be a reason to have PI be an instance variable that could be changed for each instance. Instead, by making it static, you don't have to have an instance to use it, you just use Math.PI.
I hope that makes sense. It took me a few months with of an ineffective instructor before I really understood the significance of the modifiers static, protected, private, etc. Hopefully I'm not being equally ineffective now. :)
Rich