Abstract Class with Static Methods

[bugger]

I am in need of an advice. I am designing my application and want to know when to use abstract class with static methods?

Abstract calls cannot be instantiated. If I don't declare the methods in Abstract class static, how can I call them?

Thanks.
--------

[CaptainMorgan]

Quote:

Originally Posted by bugger

I am in need of an advice. I am designing my application and want to know when to use abstract class with static methods?

Abstract calls cannot be instantiated. If I don't declare the methods in Abstract class static, how can I call them?

Thanks.
--------

If I understand your question correctly, you simply need to extend the abstract class.

Code:

public abstract class AbstractExample {
  public static void foo() {
    System.out.println("Static foo called.");
  }
  
  public void bar() {
    System.out.println("Non-static bar called.");
  }  
}

Code:

public class AbstractCaller extends AbstractExample {
  public static void main(String[] args) {
    AbstractCaller ac = new AbstractCaller();
    ac.foo();
    ac.bar();
  }      
}

Output:
Static foo called.
Non-static bar called.

Hope this helps, see this Sun topic for more info.

[bugger]

Thanks.
But you are calling both methods (foo and bar) with the object (ac). What role the static method played here?

[tim]

Hello bugger

CaptainMorgan's example explains how to call the static and non-static methods and not why someone would like to do that. Static methods can only access static attributes of a instanced class. For example:

You have a class called Dog with a static field called numberOfDogs. In the constructor of Dog you can increment numberOfDogs and if you override the finalize method then you can decrement numberOfDogs. This way you can track how many Dog objects that you have created thanks to the static modifier. Now, you can add static methods to the Dog class to manipulate numberOfDogs without you having to create an instance of Dog

Hope this helped.

[bugger]

Thanks tim.
Got it.