Hi,
On 18.06.2010, at 17:02, Loic Petit wrote:
> Hi everyone,
>
> I want to know if there is a "clean" way to do this thing.
>
> I've got a class with the following form:
>
> @Component
> @Provides
> class A {
> @Requires
> private B[] b;
> }
>
> This component is then created by the iPojo API via its factory.
> What I would like to do: give a ldap filter on the creation of the instance
> in order to have the array that matches the filter.
>
> It is possible to do that offline by giving a filter in the annotation, but
> it is impossible to have a dynamic one.
>
> As an example, I use felix/ipojo to manipulate UPnPDevice. I have a generic
> component that operate on all the devices that matches the ID given by the
> property. Here is how I could do it.
>
> class A {
> @Requires
> private UPnPDevice[] devices;
> @Property
> private String udn;
>
> public void foo() {
> for all devices that matches the udn {
> bar();
> }
> }
> }
>
> But this is a bit silly as I subscribe for all kinds of devices and then I
> do manually the filter while it is possible to subscribe to the context that
> I want only that filter. The second way, of course, is to ignore iPojo and
> subscribe on my own with a custom filter and also manage the list.
>
> It's not the first time I encounter this problem and iPojo has all the tools
> to do such thing. Do you know a "clean" way to do it ?
Each instance declaration can customize the dependency filters.
Let's imagine a component:
@Component
@Provides
class A {
@Requires(id="B") // I give a name to this dependency
private B[] b;
}
Then, in the instance declaration, you can set / override the dependency filter:
<instance component="...A">
<property name="requires.filters"> <!-- special property to customize the
filters -->
<property name="B" value="(your_filter)"/> <!-- the filter here -->
</property>
</instance>
(More details on
http://felix.apache.org/site/service-requirement-handler.html#ServiceRequirementHandler-FilteredRequirement)
Unfortunately, this mechanism is only possible if you declare the instance
using the XML formalism or the iPOJO Factory service (API). Indeed, the config
admin does not support maps (requires.filters is a map).
Regards,
Clement
>
> LP
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