Request for comments: Bug 6306820

[Michael McMahon]

Richard Kennard wrote:
> Alan,
>
> Thanks for your continued support.
>
> I find the 'static factory method' approach interesting, but I'm a 
> little confused. You cite 'being able to return a subclass' as an 
> advantage. However, you also recommend a private constructor and 
> classes with private constructors can never be subclassed?
>
> Regards,
>
> Richard.
>
>
>
Hi Richard,

I think one of the design goals for this class was to make sure it is 
easy to use
in JSPs. Do you know if it makes much (or any) difference to JSP 
applications
whether objects are created by constructor or by static factory method.

Static factory methods are definitely useful if we think that it might 
be useful to
have different implementation classes in the future, or where there may be
important differences in the ways that these objects are created in the 
future.
This can be addressed by using different createXXXX() method names.
Also, I believe that there will be some work done in jdk7, which addresses
the tagging of factory creation methods more clearly, so they stick out 
in the
documentation a bit more.

I also quite like the idea of method chaining, but again that is not a 
critical question at this
point. We should discuss this point definitely, when it comes to 
finalising the API
after the CCC approve the initial proposal.

The main question I think is concerning the mutabilty of the object and 
whether
to expose the implementation map. Clearly, the object has to be mutable, 
and it
probably needs to be specified as being unsynchronized. I think I agree 
with Alan
about the danger of exposing the internal map. Even if it does not cause 
a problem
initially, it could seriously restrict how the class develops in the future.

- Michael.