[jira] [Commented] (CAY-1559) Use Lifecycle Annotations as markers on PersistentObject methods

["Mike M Pestorich (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CAY-1559?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13693223#comment-13693223 ] 

Mike M Pestorich commented on CAY-1559:
---------------------------------------

Just a note... we've been using this patch in production for over two years now against various builds tracking trunk and have not had any issues. I'd be happy to write and submit some tests for this if it would help get this pulled into the trunk.
                
> Use Lifecycle Annotations as markers on PersistentObject methods
> ----------------------------------------------------------------
>
>                 Key: CAY-1559
>                 URL: https://issues.apache.org/jira/browse/CAY-1559
>             Project: Cayenne
>          Issue Type: Improvement
>          Components: Core Library
>    Affects Versions: 3.1M3, 3.1 (final), Short term future, Undefined future
>            Reporter: Mike M Pestorich
>            Priority: Trivial
>              Labels: annotations, listener
>         Attachments: LifecycleAnnotationMarker.patch
>
>
> In my current project I have various abstract classes that my persistent objects inherit from. While experimenting with various new ways of using lifecycle listeners and their corresponding annotations available in 3.1, I found myself wanting to annotate a method on one of those abstract classes (say with @PostAdd) and have it act as a callback on all of its subclasses. Out of the box, I could get this to work the way I wanted by doing something like:
> public class SomeAbstractPersistantObject {
>     ...
>     @PostAdd(SomeAbstractPersistantObject.class)
>     public void onPostAdd(Object object)
>     {
>         object.getObjectId() ... 
>     }
> }
> And then later on registering the listener by doing something like:
> serverRuntime.getDataDomain().getEntityResolver().getCallbackRegistry().addListener(new SomePersistentObject());
> The problem was that I didn't what to have to instantiate an object just to register it, or for that matter even have to register the listener in the first place. My callback is already part of the PersistentObject that it applies to and as such should "just work" for that object or anything that extends it. I wanted to be able to do something like:
> public class SomeAbstractPersistantObject {
>     ...
>     @PostAdd
>     public void onPostAdd()
>     {
>         this.getObjectId() ... 
>     }
> }
> And that's it. Listeners/Callbacks defined in this manner are registered when lazy initialization of the callback registry occurs within the EntityResolver. All I have to do now is annotate a method within the persistent object that I want it to act on and don't have to worry about anything else.
> I don't know if this sort of thing would be useful to anyone but I have attached a patch that I believe does just that. I have been using it for a couple of days now and it seems to be working as intended without breaking the other available means of using lifecycle listeners.

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