[jira] [Updated] (SLING-4447) Improve JavaUseProvider to not fall back to a simple Pojo instanciation in case a Java class with @Model annotation cannot be instanciated

["Konrad Windszus (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/SLING-4447?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Konrad Windszus updated SLING-4447:
-----------------------------------
    Attachment: SLING-4447-v01.patch

Attached is a patch for Sling Models which adds a UseProvider for Sling Models. That UseProvider will throw exceptions in case it deals with a class having a model annotation which could not be instanciated. In all other cases it will fail silently.

The dependency to Sightly and the Sling Classloader is optional, so the whole component is not there in case the dependencies cannot be fullfilled.

[~radu.cotescu] Could you review the patch? Also I do have a question regarding the service ranking (SLING-4454). Maybe you can clarify that?

> Improve JavaUseProvider to not fall back to a simple Pojo instanciation in case a Java class with @Model annotation cannot be instanciated
> ------------------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: SLING-4447
>                 URL: https://issues.apache.org/jira/browse/SLING-4447
>             Project: Sling
>          Issue Type: Improvement
>          Components: Scripting
>    Affects Versions: Scripting Sightly Engine 1.0.0
>            Reporter: Konrad Windszus
>            Assignee: Konrad Windszus
>         Attachments: SLING-4447-v01.patch
>
>
> Currently in case a Java class is a Sling Model (i.e. has the Model annotation) and cannot be instanciated (e.g. required injections not possible) Sightly falls back to instanciate those as simple Pojos.
> This is never good, since a lot of NullPointerException happen then, because all injections have not been performed then.
> Therefore in the following code should be used instead 
> {code}
> if (modelFactory.isModelClass(resource, cls)) {
>   if (modelFactory.canCreateFromAdaptable(resource, cls)) {
>     obj = modelFactory.createModel(resource, cls);
>   } else if (modelFactory.canCreateFromAdaptable(request, cls)) {
>     obj = modelFactory.createModel(request, cls);
>   } else {
>     throw new IllegalStateException("Could not adapt the given Sling Model from neither resource nor request: " + cls);
>   }
> }
> {code}
> That way, exceptions would be propagated in case a Sling model cannot be instanciated and developers more easily see why the Sling Model does not work (instead of running into NullPointerExceptions in their model because it was instanciated as simple 



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)