Re: Static vs non static methods - best practice

From:
Lew <lew@lewscanon.com>
Newsgroups:
comp.lang.java.programmer
Date:
Fri, 02 Nov 2007 18:21:20 -0400
Message-ID:
<Me6dnRHPAIt9P7banZ2dnUVZ_tqtnZ2d@comcast.com>
m97rek wrote:

If I have a class that looks something like:

public class SampleApp extends Engine implements Listener_OnMyEvent
{

  public static void main(String argv[])
  {
    int x=10;

    //Call metod1
    Method1(x);


You don't show us any method "Method1(int)". What is that method?

  }

  public method1(int i)
  {
    //Call a method from the Engine Class
    //I know I don't have to have "Engine." here but it's just to
clearify
    Engine.method2();
  }
  public void OnMyEvent()
  {
    Log("Event Hapended");
  }
}

Let's say now that I want to move method1 to another class/file in
order to keep the code as neat and tidy as possible.


That's not an engineering reason. Methods go with the class whose behavior
they implement.

How should I do that? What is best practice according to you? Should
the methods there be static?


Static methods are for class-wide behaviors. It's not about making things
"neat and tidy". If a behavior belongs to the whole class, as with utility
classes or factory methods, then make the method static, otherwise make it
instance-level. If you're not sure, and the class is instantiable, make it an
instance method.

Methods reflect your object model. If your model says that there is a
business object type "Foo", and that Foo thingies do certain behaviors, then
you implement that with a class Foo and methods in that class implement those
behaviors (preferring instance level over static where feasible).

I tried to create:

public class MyMethods
{
  public static method1(int i)
  {
    Engine.method2();
  }

}
....but then method2 isn't available since Engine isn't implemented
unless I pass the whole class along:
MyMethods(x, this)


Huh? You lost me on this point. What is Engine?

Since its name begins with an upper-case letter, it must be a class. Since
you invoke method2() (no arguments) via Engine, it must be a static method.

MyMethods(x, this) is a constructor, but you haven't shown us this constructor.

Is this correct?


No.

I hope you see what I'm getting at here.


No.

You really, really need to read and follow
<http://www.physci.org/codes/sscce.html>

Provide us with an SSCCE. If you can't compile the code then we can't either.

Daniel Pitts wrote:

Actually, static means it IS accessible by Engine.method2();

Though in general an abundance of static methods suggest that your OO
design has a flaw.


--
Lew

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