variables 2005-10-10 - By Tim Wood
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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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