[threeten-dev] Some observations of chrono ser

[roger riggs]

Hi  Sherman,

On 3/12/2013 5:52 PM, Xueming Shen wrote:
> Hi,
>
> (1) Chronology.writeReplace() is private, so the proxy Ser mechanism
> is actually disabled for all Chronology subclasses. Is it intentional? 
> Given
> all JDK subclasses all have readResolve() defined (3 out of 4 to return
> the singleton) I would assume the Ser delegation might not be necessary,
> though it might be still desirable to "enforce" the Ser pattern here?
Not quite, but still broken.  The writeReplace method can be private but
is used only if the Chronology class is Serializable.
http://docs.oracle.com/javase/7/docs/platform/serialization/spec/output.html#5324

The subclasses are serializable and that is triggering the default 
serialization.

Is there an issue for this?
>
> (2) Chronology.initCache() tries to load the Chronology implementation
> from the ServiceLoader before initializing/registering the built-ins, 
> is it
> intentional? If yes, the current implementation as described in (1) may
> have an un-desired impact to this design intention. For example, if a
> Japanese Chronology in a VM with built-in ja chronology is transferred
> to a VM that has a "customized" Japanese Chronology registered, the
> current implementation may force to use the built-in (as the Ser 
> mechanism
> is off/out now), the Chronology.of(id) logic in Chronology.readExternal()
> will never kick in and the "registered/customized" Japanese chronology
> will not be used for the deser-ed chronology.
It was intentional that the ServiceLoader defined Chronologies would
supercede the built-in ones allowing replacement if as part of 
customization.
It may deserve more discussion.

>
> (3) ChronoDateImpl also declares "Serializable", given all its 
> subclasses have
> their own declaration of Serializable() and the writeReplace()/write/read
> External(), this might not be necessary?
It does seem unnecessary duplication.

Roger

>
> -Sherman

-- 
Thanks, Roger

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