| A factory for creating BackingStore(s). Every provider must provide an
implementation of this interface.
The createBackingStore(env) method is called typically during
container creation time. A store instance is typically used to store state
for a single container whose id is passed (as appId) to
createStore() method.
The createBatchBackingStore() method will be called whenever
the container decides to save a set of states that belong different
applications. Thus the store returned by createBatchBackingStore method is
different from createBackingStore in that the data passed in the collection
may potentially be from different containers/applications.
Any runtime exception thrown from createBackingStore and
createBatchBackingStore method will cause the container to use a default
persistence-type (typically no replication) and a log message will be logged
at WARNING level.
Both BackingStore and BatchBackingStore must be
thread safe. | 