[transitive] Transitive Persistence for play 1.2.x

JPA as a standard is all about transitive persistence. Within a JPA transaction, any change to
any object that is managed by the EntityManager will result in propagation
of those changes back into the database. The easiness of this automatism is
something that took the Java Enterprise world quite some time to achieve.

The inventors of play, however, don’t see the value in this achievement and try to resemble
the logic that is found in other web frameworks like Ruby on Rails, where the save operation
is an explicit step to ask for. Therefore, in play you will need to call save() on any object
whose changes you want to be committed to the database. If you have to manage a larger object
graph, this behavior is very error-prone and annoying to code.

see more here => http://pareis.com/2012/10/02/jpa-transitive-persistence-for-play-framework/

Benefits of this module

This module brings the original behavior of JPA’s transitive persistence back into the play framework.
The API is exactly the same as in out-of-the-box play with the exception that it is necessary to inherit
your model classes from a different base class. And then, instead of calling save on every object you want to
have saved to the DB, it is merely necessay to call persist() on newly created objects.
Every other change (update, deletion by orphanation) is handled by JPA in the standard way.

Using the module

add an entry to your dependencies.yml:

# Application dependencies

require:
    - play
    - pareis -> transitive 0.1

repositories:
    - playModules:
         type:     chain
         using:
              - bintray:
                   type: http 
                   artifact: "http://dl.bintray.com/[organisation]/play-modules/[module]-[revision].zip"
                   contains: 
                      - pareis -> transitive

              - playLocalModules:
                   type:       local
                   descriptor: "${play.path}/modules/[module]-[revision]/conf/dependencies.yml"
                   artifact:   "${play.path}/modules/[module]-[revision]"
                   contains:
                        - play -> *

Written by André Pareis