[picocontainer-dev] Config , Properties and API struggle

Hi all, 

Currently we have some limited support for
configuration entities. And it looks to me not only
limited, but
also not so pretty. 

Ugliest part of it ( IMHO of course ) is
MutablePicoContainer.addConfig(String, Object) - as it
just a wrapper for adding instance adapter and does
not introduces any new semantics. 

There is also some ugliness in "by param
name"-fallback in dependency resolution ( which by
chance breaks nano-groovy )- why do we need this at
all? It usefullnes is quite limited (and I would say
potentially dangerous and confusing for users - 
try to explain them why it is needed to use certain
formal  parameter names in constructors ) 

Anyway I think that reference to [external] 
configuration item shall be always explicit. 
And place them into special parent containers 
(like attributed) is generally good idea, but needs
some improvement. 

Current implementation by Paul supports only 
integers, booleans and strings - which is not very
generic approach. It would be really cool to support 
more (at least all primitives from java.lang , maybe
java.io).  Another prolem is, that it registers
components with certain type ASAP - but it is 
depending component which decides what type his config
entry is (say, the same property could be needed as
string or number. or integer / float) 

Anyway, current approach with component adapters  /
parameters would not allow such "miltitype" extraction
(because adapter has to know early which type it will
be serving, and has no information from parameter
which type is being required - adapter is passive part
in 
hunt for dependencies)

I propose API change so that adapter can be queried,
whether it would provide certain data type, instead
generally hardwiring it (well, classical adapters 
will be hardwired anyway)  - this way parameters could
resolve the same "config" adapter for different 
types. We will also need mechanism to ask such adapter
for certain type, prompting conversion from string.

comments and ideas are appreciated. 

regards,

----[ Konstantin Pribluda http://www.pribluda.de ]----------------
JTec quality components: http://www.pribluda.de/projects/


       
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