[jira] [Comment Edited] (FELIX-5996) Remove generic parameter in DM Component interface

["Pierre De Rop (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FELIX-5996?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16712100#comment-16712100 ] 

Pierre De Rop edited comment on FELIX-5996 at 12/6/18 10:40 PM:
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I have attached a new version which is not using generic parameters anymore; the methods from the Component interface have been duplicated in all Component sub interfaces.

note that the AbstractComponent interface has been removed.

 


was (Author: pderop):
I have attached a new version which is not using generic parameters anymore; the methods from the Component interface have been duplicated in all Component subinterfaces.

 

> Remove generic parameter in DM Component interface
> --------------------------------------------------
>
>                 Key: FELIX-5996
>                 URL: https://issues.apache.org/jira/browse/FELIX-5996
>             Project: Felix
>          Issue Type: Task
>          Components: Dependency Manager
>    Affects Versions: org.apache.felix.dependencymanager-r13
>            Reporter: Pierre De Rop
>            Assignee: Pierre De Rop
>            Priority: Minor
>         Attachments: dependencymanager.FELIX-5996.tgz
>
>
> Since dm-r13, the Component interface is now taking a generic parameter so it make it easier to define extended components like adapters.
> So, with this new model, it looks like the following:
> {code:java}
> public interface Component<T extends Component<T>> {
>    T setInterface(String service, Dictionary properties)
>    T setImplementation(Object ob);
>    ...
> }
> public interface AdapterComponent extends Component<AdapterComponent> {
>    AdapterComponent setAdaptee(Class<?> service, String filter);
>    AdapterComponent setAdapteeCallbacks(String add, String change, String remove, String swap);
>    ...
> }
> {code}
> and you can now do something like this:
> {code:java}
> Component adapter = createAdapterComponent()
>   .setAdaptee(Adaptee.class, "(foo=bar)")
>   .setAdapteeCallbacks("setAdaptee", "changeAdaptee", null, null)
>   .setImplementation(AdapterImpl.class)
>   .setInterface(AdapterService.class, null)
>   .add(createServiceDependency().setService(LogService.class));
> {code}
> now, while using the generic parameter simplify the declaration of component adapters, it has a drawback: the Component now takes a generic parameter, and old code using simple components now generates a compilation warning:
> {code:java}
> Component adapter = createComponent()
>  .setImplementation(SimpleComponent.class)
>  ...
> {code}
> so, the above example generates a compilation warning, and you now have to declare "?" in order to get rid of the warning:
> {code:java}
> Component<?> adapter = createComponent()
>  .setImplementation(SimpleComponent.class)
>  ...
> {code}
> that being said, maybe we can refactor in order to get rid of the generic parameter, by copying the top level component methods in sub interfaces, like this:
> {code:java}
> public interface Component {
>  Component setInterface(String service, Dictionary properties);
>  Component setImplementation(Object ob);
>  ...
>  }
> public interface AdapterComponent extends Component
> {
>  // Component methods with specialized signatures 
> AdapterComponent setInterface(String service, Dictionary properties) 
> AdapterComponent setImplementation(Object ob);
> // AdapterComponent methods
> AdapterComponent methods AdapterComponent setAdaptee(Class<?> service, String filter); 
> AdapterComponent setAdapteeCallbacks(String add, String change, String remove, String swap); 
>  }
> {code}



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