If you get data from a DB to fill a publication when it is created, you should use a DataController.

The main difference is about when and where the DataController/StoreListener is called :

• A DataController is called before and after any write operation on the replica it occurs. Furthermore, a DataController can check the data integrity and validity.
• A StoreListener is called after a write operation has been processed. There are 3 possible cases:
  1. after the write operation occurs ;
  2. when the store is loaded ;
  3. when this operations is received on a replica (through JSync protocol).

Some practical differences :

1. A DataController can prevent or modify a write ; a StoreListener cannot.
2. A StoreListener can be called at JCMS start-up (when the store is loaded) ; A DataController is only called at the very first time the write operation occurs.
3. A StoreListener can be called on any replica ; a DataController is only called on the replica which has performed the action.

Which one to use?

• DataController :
  1. To check data integrity ;
  2. To check if a write operation is valid ;
  3. To modify the content of an object before the write operation ;
  4. To trigger an action before or after a write operation if this action must be triggered only once.
• StoreListener:
  1. To manage data index ;
  2. To trigger an action for each replica ;
  3. To trigger an action each time the store is loaded.