Thanks Craig,
I've got to say though that this seems exceedingly complicated for something
that one might imagine you'd need to do in every non-trivial Jersey app.
By way of comparison, in the Restlet framework, you just do something like:
router.getContext().getAttributes().put("databaseConn", dbConn);
You can then access it within the resource with something like:
Connection conn = (Connection) context.getAttributes().get("dbConn");
Why is this so much more complicated with Jersey?
I switched to Jersey from Restlet because on the surface it looked simpler
and more elegant, I regret to say that I'm now having doubts about this
decision :-/
(I'm not attacking those who've been kind enough to respond to my questions,
I'm grateful for that - I'm just hoping that someone can convince me that
either this isn't as complicated as it appears, or that there is a good
justification for the complexity).
Ian.
On Mon, Mar 23, 2009 at 9:48 PM, Craig McClanahan
<Craig.McClanahan_at_sun.com>wrote:
> Ian Clarke wrote:
>
> Thanks for that.
>
> Can you point me to a simple example of using the Injectable annotations?
>
> One example is in the contribs/jersey-multipart project, where I wanted to
> be able to inject an instance of "com.sun.jersey.multipart.MultiPartConfig"
> into my resource classes. I wrote a provider for this in class
> "com.sun.jersey.multipart.impl.MultiPartConfigProvider" and configured it
> with a
> "src/main/java/META-INF/services/com.sun.jersey.multipart.impl.MultiPartImplProvider"
> file that has to end up in META-INF/services in your WEB-INF/classes
> directory or inside a jar in WEB-INF/lib.
>
> This lets me inject resources (using @Context, as you correctly surmised)
> into classes like com.sun.jersey.multipart.impl.MultiPartReader.
>
> In my case, I declared that MultiPartConfig was a singleton, and created it
> in the getInjectable() method (which will only get called once because of
> the scope value).
>
> For dealing with JDBC, here's what I would suggest:
>
> * Configure a JDBC DataSource in the JNDI environment for your application.
>
> * In the getInjectable() method of your provider, do a JNDI lookup to get
> the
> DataSource instance.
>
> * Make the class of the injected object have a getDataSource() method on it
> that returns this data source instance.
>
> * In a resource method that received the injected object, have it call
> getDataSource().getConnection() on the injected object to get a
> connection,
> and then call connection.close() when you are through to return that
> connection
> to the data source's pool. Be sure you do this close even if an
> exception
> gets thrown along the way.
>
> The last step ensures that you won't have two (or more) simultaneous
> requests fighting over the same JDBC Connection instance, which is not
> allowed.
>
> Craig
>
>
> Ian.
>
> On Mon, Mar 23, 2009 at 7:19 PM, Erdinc Yilmazel <erdinc_at_yilmazel.com>wrote:
>
>> Hi,
>>
>> You may write your own Injectables and InjectableProviders for
>> injecting custom objects. You may even define your own annotations for
>> that. See :
>>
>> com.sun.jersey.spi.inject.Injectable
>> com.sun.jersey.spi.inject.InjectableProvider
>> com.sun.jersey.spi.inject.Inject
>>
>> After writing and InjectableProvider you must annotate it with
>> @Provider annotation to make Jersey aware of that class.
>>
>> The @Context annotation has also its InjectableProvider.
>>
>> The other choice is using a IOC framework like google guice. Support
>> for google guice may be bundled with the upcoming 1.0.3 version of
>> Jersey, but you can find an example code in jersey subversion
>> repository.
>>
>> Erdinc
>>
>> On Mon, Mar 23, 2009 at 11:33 PM, Ian Clarke <ian.clarke_at_gmail.com>
>> wrote:
>> > I have an object, lets say a SQL connection, that I want my Jersey
>> resource
>> > classes to have access to, but I don't want to make the SQL connection
>> > static (because some day there may be more than one of them).
>> >
>> > How do I inject an object like this into a resource class so that it can
>> use
>> > it? For that matter, how do I tell resource classes about any objects
>> > without making them available statically?
>> >
>> > I have a feeling it may be something to do with the @Context annotation,
>> but
>> > I haven't been able to find clear documentation on this.
>> >
>> > Any help would be appreciated,
>> >
>> > Ian.
>> >
>>
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>>
>
>
> --
> Ian Clarke
> CEO, Uprizer Labs
> Email: ian_at_uprizer.com
> Ph: +1 512 422 3588
> Fax: +1 512 276 6674
>
>
>
--
Ian Clarke
CEO, Uprizer Labs
Email: ian_at_uprizer.com
Ph: +1 512 422 3588
Fax: +1 512 276 6674