Re: startup code

From:

Eric Sosman <esosman@ieee-dot-org.invalid>

Newsgroups:

comp.lang.java.programmer

Date:

Wed, 29 Aug 2012 17:14:05 -0400

Message-ID:

<k1m0mu$1bl$1@dont-email.me>

On 8/29/2012 4:06 PM, Robert Klemme wrote:

On 29.08.2012 21:41, Eric Sosman wrote:

     "What she said," with a stylistic suggestion: If the code to
create the bitmap grows to more than a very few lines, consider
putting them in a private static method of their own and calling
that method from the static initializer:

     class Thing {
         ...
         static {
             createTheBitmap();
         }

         /** Called only during class initialization. */
         private static void createTheBitmap() {
             // create the bitmap
         }
         ...
     }

Doesn't change the code's meaning in any significant way, but
may make it easier to debug/adapt/refactor later on.

If you go through the effort why then call it from an initializer? Why
not just via the field declaration that holds the bitmap?

class Thing {
   private static final BitMap bm = loadTheBitmap();

   private static BitMap loadTheBitmap() {
     ...
     return ...;
   }
}

Assuming that the state will be held in this class.

If the result of "create the bitmap" is a single value that
is stored in a single field, sure -- but that's an assumption.
For more general class initialization I think it would be
misleading to hide the setup of several fields behind what
looks like an initializer for just one of them.

--
Eric Sosman
esosman@ieee-dot-org.invalid