Re: [infinispan-dev] Distributed Executors in write mode, need reference to Cache
On 21 Dec 2011, at 15:30, Vladimir Blagojevic wrote:
Pete, a bit more guidance please :-) I read
http://docs.jboss.org/weld/reference/latest/en-US/html/extend.html and I
looked at the infinispan-cdi code and how InfinispanExtension class
wires into CDI container. I understand that part, well, sort of! I've
seen how a class whose instances are supposed to be injected
(DefaultCacheManager, AdvancedCache) is "prepared" for CDI in our
infinispan-cdi module.
Take a look at
http://seamframework.org/Documentation/HowDoIDoNoncontextualInjectionForA....
However, as I guess you don't want CDI directly in the map/reduce stuff, I'm
suggesting you create an SPI so that injection frameworks can be plugged in.
>
> Here is the SPI that CDI has for this purpose:
>
> http://docs.oracle.com/javaee/6/api/javax/enterprise/inject/spi/Injection...
>
> I would suggest modelling after it, as it's proved successful, and will make CDI
integration easy. (BTW I don't mean use it directly, I mean copy and paste it into
infinispan code).
I do not understand this part. What do you mean by "copy and paste this
into Infinispan code"? Making sure we are on the same page: instances of
Mapper (or Reducer) do not need to be injected somewhere; they are
provided by the user and used in conjunction with MapReduceTask.
Yep.
Implementations of Mapper/Reducer interface need to have its field
injected, once they are deseralized to remote Infinispan nodes, injected
with appropriate Cache instance for example.
Yep. This is what CDI calls an "injection target" (an object which is the target
for injection). So, what i would suggest you do is add an SPI to the map/reduce code that
has callbacks which can be hooked into at the appropriate point by CDI or something else.
So you would want a callback for inject(), postConstruct() and preDestroy(). You would
provide a default impl for plain old java, which were basically no-ops, and then use e.g.
the service loader to load other implementations, and call back to them. You then call
this SPI at the relevant points in your code.
Does that make any more sense?