variables 2005-10-10 - By Frans Verhoef
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To add on to this, I would also like to highlight that in general you wouldn't
want to initialize a static variable inside a constructor. This could lead to
funny unexpected results, as every time you create a new object of your class,
the value of your static variable changes for all of your class instances (as a
static variable is shared among all objects of the same class).
Frans
On Mon, 10 Oct 2005 11:40:56 -0700, Tim Wood wrote:
>?At 07:09 AM 10/10/05, SUBSCRIBE EJB-INTEREST anonymous wrote:
>
>>?Hi,
>>?Is there any advantage of having private,static member variable
>>?(Initialized in the constructor of the class) in a non-singleton
>>?class. Is so, please let me know.
>>
>
>?To answer this, think about what that decl means: The class needs a
>?single copy of the variable to use as an implementation detail.
>?Preferably, the variable is fina, and, if it's a reference type,
>?the object it points to is immutable. ?Then no synchro. issues.
>?For clean initialization, set it up in a static block; this is a
>?good thread-safe way to build singletons too (R. Johnson).
>
>?If the object is mutable, say some master state table for all the
>?instances, then you synchronize it. Since it is private &?static,
>?you don't put the synchronization in the method signatures, but
>?synchronize explicitly on the object itself inside the class.
>
>?HTH,
>?TW
>
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