Re: How to use references using multiplicity="1..n" with binding.ws or binding.rmi

[Simon Laws]

On Mon, Apr 28, 2008 at 3:37 PM, <[EMAIL PROTECTED]> wrote:

> Hi all,
>
> I have another question concerning multiplicity. Given my sample
> configuration
>
> <component name="CrawlerControllerComponent">
>    ...
>    <reference name="crawlers" multiplicity="1..n"
> target="CrawlerComponent SpecialCrawlerComponent">
>         <binding.sca />
>    </reference>
>
> </component>
>
> <component name="CrawlerComponent">
>    <implementation.java class="impl.CrawlerImpl"/>
>     <service name="Crawler">
>        <interface.java interface="interfaces.Crawler" />
>
>     </service>
> </component>
>
> <component name="SpecialCrawlerComponent">
>    <implementation.java class="impl.SpecialCrawlerImpl"/>
>     <service name="Crawler">
>        <interface.java interface="interfaces.Crawler" />
>     </service>
> </component>
>
>
> I want to create a ServiceReference to one of the Crawlers.
> Without multiplicity (assuming the reference name would be "crawler"),
> the code would look like this:
>
>        ServiceReference<Crawler> crawlerRef =
> componentContext.getServiceReference(Crawler.class, "crawler");
>        return crawlerRef.getService();
>
>
> But How can I achieve this using multiplicity ? How can I choose for
> what target a ServiceReference is created?
> By simply using this code
>        ServiceReference<Crawler> crawlerRef =
> componentContext.getServiceReference(Crawler.class, "crawlers");
>        return crawlerRef.getService();
> always a ServiceReference to the first target (CrawlerComponent) is
> created.
>
>
> Bye,
> Daniel
>

Hi Daniel

Good question. The OASIS TC has proposed a solution to this issue (
http://www.osoa.org/jira/browse/JAVA-9) but this isn't part of the API we
have implemented as we have taken the V1 API. Can you raise a JIRA for this
as I can't see one already and at least in that way we can track it.

Is it possible for you to inject the references you need. You can specify a
reference with multiplicity as a collection, for example, from
itest/references


    @Reference(name = "dServiceReferences")
    public List<ServiceReference<DComponent>> dServiceReferences;

Which is populated by

    <component name="AComponent">
         ...
        <reference name="dServiceReferences" target="DComponent DComponent1"
/>
    </component>

    <component name="DComponent">
        <implementation.java
class="org.apache.tuscany.sca.itest.references.DComponentImpl" />
    </component>

    <component name="DComponent1">
        <implementation.java
class="org.apache.tuscany.sca.itest.references.DComponentImpl" />
    </component>

See the test for alternatives.

Regards

Simon