Loosen Constructor super()/this() call restrictions

[Marek Kozieł]

2009/3/23 Mark Mahieu <markmahieu at googlemail.com>:
> 2009/3/23 Jeremy Manson <jeremy.manson at gmail.com>
>>
>> For example, now that this() and super() can come in the middle of a
>> constructor, are the semantics implicitly changed so that you can
>> catch exceptions thrown by this() and super()?  Does that mean that
>> objects can now be seen as partially initialized in sub-constructors?
>>
>
> Ha, there's a bug entry for that one too:
> http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4879515
>
> Mark
>
>

this() super() work 100% correctly now days.

But maybe the thing you need is not this 'weird' behavior of constructor.

Consider new kind of method 'initializer':
 - Can be executed only in constructors.
 - Can assign value to final fields, only condition is to assign it always.



class Sample{
   final Foo foo;
   final Bar bar;

   public Sample(FooBuilder foo, Bar bar){
      initFoo(foo); // compiler known that foo is assigned
      this.bar = bar.copy();
   }

   public Sample(FooBuilder foo, BarBuilder bar){
      initFoo(foo); // compiler known that foo is assigned
      initBar(bar); // compiler know that bar is assigned
   }

   public Sample(Foo foo, BarBuilder bar){
      this.foo = foo.copy();
      initBar(bar); // compiler know that bar is assigned
   }

   initializer void initFoo(FooBuilder foo){
      //operations to create foo
      // we have foo
      this.foo = foo;
   }

   initializer void initBar(BarBuilder bar){
      //operations to create  bar
      // we have  bar
      this. bar = bar;
   }

}



-- 
Pozdrowionka. / Regards.
Lasu aka Marek Kozieł

http://lasu2string.blogspot.com/