What are the differences between GemfireRepository and CrudRepository in spring data gemfire

1
votes

GemfireRepository is a gemfire specific implementation of CrudRepository but the spring data gemfire reference guide says if we use GemfireRepository then we need to have our domain classes correctly mapped to configured regions as the bottstrap process will fail otherwise..does that mean that we need to have @Region annotation on the domain classes?In case we use CrudRepository then @Region annotation is not required because CrudRepository is not dependent on Region ?

So I am using GemfireRepository and I have a cacheloader configured as plug in to a region and the cacheloader depends on the GemfireRepository to fetch the data from RDBMS. So according to the reference documentation if GemfireRepository is internally dependent on Region..then does that create a circular dependency?

1
spring-data-gemfire

1 Answers

0
votes

The SDG GemfireRepository interface extends SDC's CrudRepository interface and adds a couple of methods (findAll(:Sort), and an overloaded save(:Wrapper):T method), See...

http://docs.spring.io/spring-data-gemfire/docs/current/api/org/springframework/data/gemfire/repository/GemfireRepository.html

GemfireRepository interface is "backed" by the SimpleGemfireRepository class.

Whether your application-specific Repository interface extends GemfireRepository or CrudRepository, or even just org.springframework.data.repository.Repository, does not really matter. Extending a Repository interface provided by the framework only determines what methods will be exposed in the backing implementation by the "Proxy" created with the framework.

E.g. if you wanted to create a read-only Repo, you would directly extend org.springframework.data.repository.Repository, and copy only the "read-only" methods from the CrudRepository interface into your application-specific Repository interface (e.g. findOne(:ID), findAll(), exists(:ID), i.e. no data store mutating methods, such as save(:S):S).

But, by using the namespace element in your Spring config, you are instructing the framework to use SDG's Repository infrastructure to handle persistent operations of your application domain objects into GemFire, and specifically Regions. Therefore, either the application domain object must be annotated with @Region, or now, SDG allows an application Repository interface to be annotated with @Region, in cases where you want your application domain object needs to be stored in multiple Regions of GemFire. See 8.1, Entity Mapping in the SDG Ref Guide, for further details..

http://docs.spring.io/spring-data-gemfire/docs/1.4.0.RELEASE/reference/html/mapping.html#mapping.entities

Regarding the "circular dependency"... yes, it creates a circular dependency...

Region A -> CacheLoader A -> ARepository -> Region A.

And will lead to a...

org.springframework.beans.factory.BeanCurrentlyInCreationException

You need to break the cycle.