I became familiar with this extension of the Adapter pattern when I started
writing plugins for Eclipse. Eclipse has a similar class,
org.eclipse.runtime.core.AdapterManager, that is used a lot.
The AdapterManager is absolutely addicting. I will never again go without
an 'AdapterManager'. And I hardly ever write code like this anymore...
MyInterface lInterface= (MyInterface)someClass;
...I always write...
MyInterface lInterface=
(MyInterface)AdapterManager.getAdapter(MyInterface.class, someClass);
The AdapterManager is especially useful when some plugin wants to add an
interface to objects that were created by another third party plugin.
However, I haven't yet created one for myself for use outside of Eclipse.
I already use commons lang and would very much like to see the
AdaptorRegistry added.
thanks,
ted stockwell
jlense.sf.net
> -----Original Message-----
> From: Howard M. Lewis Ship [mailto:[EMAIL PROTECTED]]
>
> Tapestry already uses a lot of Jakarta commons stuff (-lang,
> -logging).
> There are some utility classes in Tapestry that I would love
> to move into
> commons-lang.
>
> One very useful candidate is AdaptorRegistry. It's my
> attempt to bring
> logic, similar to Objective-C categories, to Java. You can
> also think of it
> as lightweight aspects.
>
> http://jakarta.apache.org/proposals/tapestry/doc/clover/net/sf
> /tapestry/util
> /AdaptorRegistry.html
>
> This is my take on a general implementation of the GoF
> Adaptor pattern. You
> use an AdaptorRegistry to adapt objects with fixed interfaces to new
> situations. You create adaptor objects and register them.
> Adaptors are
> registerred in terms of a class or interface.
>
> You then supply a subject object. A search occurs, where the
> AdaptorRegistry looks for a matching adaptor. It first works up the
> inheritance hierarchy, looking for a matching superclass. It
> then works
> through all the interfaces directly, or indirectly, implemented by the
> object until it finds a match.
>
> In practice, you define an adaptor interface that takes, as
> an argument, an
> object. You them provide different implementations, where
> you cast the
> object to specific types and perform operations on or using them.
>
> This tends to replace code that is a series of "if (foo
> instanceof Bar) ..."
> with a lookup of an adaptor. Of course, you can register
> adaptors in any
> order, at any time.
>
> AdaptorRegistry has an amazing 100% code coverage test suite.
>
> It is ready for "harvest" from Tapestry. It would be minimal work to
> decouple it from Tapestry (it uses some static methods to access a
> framework-common ResourceBundle).
>
> I may find some spare cycles to provide a patch to
> commons-lang, if you are
> interested in the code.
>
>
>
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