Re: "Hello world!" without a public class?

From:
"Aryeh M. Friedman" <Aryeh.Friedman@gmail.com>
Newsgroups:
comp.lang.java.programmer
Date:
Sun, 6 Jan 2013 13:21:37 -0800 (PST)
Message-ID:
<31c0e887-032a-4311-8b23-4ce7878cc4b1@googlegroups.com>
On Sunday, January 6, 2013 4:07:17 PM UTC-5, Arne Vajh=F8j wrote:

On 1/6/2013 1:48 PM, Aryeh M. Friedman wrote:
 

Now that being said here is a good example of something that is easier=

 

 
to read then either (yes it does get compiled into something very close=

 

 
to inner classes [not nested if I remember the jargon correctly] but no=

 

 
where near as ugly):
 

 

Foo.java:

 

 

public enum Foo

 

{

 

     ACK {

 

        public void doSomething(SomeClass arg)

 

        {

 

           do what ever for ACK

 

        }

 

     },

 

     BAR {

 

        public void doSomething(SomeClass arg)

 

        {

 

          do what ever for BAR

 

        }

 

     }

 

}

 

 

Fred.java:

 

 

public class Fred

 

{

 

      public void someMethod()

 

      {

 

         SomeClass sc=new SomeClass(...);

 

         Foo[] arr=new Foo[]{ACK,BAR}; // typing this for this examp=

le so being lazy on syntax

 

 

         for(Foo elem:arr)

 

             elem.doSomething(sc);

 

      }

 

}

 

 

and voila much more readable then putting a whole rats nest of stuff in=

 the initialization of arr

 

      }

 

}

 
 
 
Given that the above is both unreadable and un-compilable, then ...
 
 
 
Arne


Ok here is some actual working code that effectively does the same thing wi=
th the psedocode filled in (including the command lines):

% cat Foo.java
public enum Foo
{
    ACK {
        public String doSomething(String arg)
        {
            return "ACK: "+arg;
        }
    },
    BAR {
        public String doSomething(String arg)
        {
            return "BAR: "+arg;
        }
    };

    public abstract String doSomething(String arg);
}
% cat Fred.java
public class Fred
{
    public static void main(String[] args)
    {
        for(Foo elem:new Foo[]{Foo.ACK,Foo.BAR})
            System.out.println(elem.doSomething("I am doing something"));
    }
}
% javac Fred.java
% java Fred
ACK: I am doing something
BAR: I am doing something

Now please tell me that does not replace inner classes (the enum constants =
are compiled as inner classes and not just straight data constants).

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