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[java] Java Design Practices

Started by eben Sep 23, 2005 at 5:56 PM 3 replies 1.2k views

Original Post

Sep 23, 2005 at 5:56 PM

When a java application enters through public static void main(String[] args) it requires that every method called from main be static as well. How can I design a class so that after entry through the main method I can can call other methods without them having to be being static. I basically dont want to end up with a class full of all static methods. What is the design convention for an issue like this? thanks.

SiCrane

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473

SiCrane

Sep 23, 2005 at 5:59 PM

Create an instance of a class in your main().

H_o_p_s

115

H_o_p_s

Sep 23, 2005 at 10:25 PM

The static keyword means that that one function/object is one function/object no matter how many instances there are. Static functions/objects don't need to be initialized.

For example:

public class StaticTest {   static String string;   int number;   public static void main(String[] args) {      StaticTest st = new StaticTest();//create an object      StaticTest st2 = new StaticTest();//create another object      st.string = "blah";//This won't work because string is static, instead call it like the following line      StaticTest.st = "blah";//This will work      st2.number = 5;//Will work      StaticTest.number = 5;//Won't work      st2.test();//This won't work because it is static      StaticTest.test();//This will work      st.test2()//Will work      StaticTest.test2();//Won't work         }   static void test() {   }   void test2() {   }}

Anyway, if you create an object first, the functions/members don't have to be static.

I might have just confused you more, but hopefully it made sense.

Whackjack

Sep 23, 2005 at 11:47 PM

H_o_p_s gave a really good (if not rather elaborate) explanation of how to do this. I rather prefer having a single class called Main that has the main() method in it. The main() method will create an instance of an Application class and call some method on it (maybe start() or something). I've always found the idiom of putting everything in a single class confusing and quite anti-Java in design.

Lucidquiet

Sep 24, 2005 at 2:48 PM

Yup all you really need is this some where:

public class Main {   public static void main(String[] args) {     new App().start();   }}//  A bit more laborous, but fun (to me) approach:public class Main {   public static void main(String[] args) {      new EntryController().setArgs(args).start();      //  setArgs() takes a String array, and in the end returns 'this'      //  this particular start also return 'this'... because I want it to   }}

Now write, App(), or EntryController, or Controller, or whatever. This works because 'new' has a higher precedence than the '.' operator.

L-

PS: You, instead, could write a static block. Get a class loader, then instantiates some class, that is Runnable, and then call:

new Thread(app).start()

(As long as you are not assigning the variable, because that start returns void (horible nomenclature)).

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