CODEWITHSUNDEEP
restspring-dataspring-data-rest
Rafael
Rafael

Reputation: 2676

How to evolve a Spring Data REST application?

I've been messing around with Spring Data REST and it's good stuff. I like the HATEOAS integration and the ALPs. It is clear that it can solve many use cases by default or with little configuration.

My concerns are:

Upvotes: 2

Views: 320

Answers (1)

Oliver Drotbohm
Oliver Drotbohm

Reputation: 83161

There's two aspects that might be interesting to solve the outlined challenges.

Using EventListeners

If all you want to do is intercept the CRUD operations backing the exposed resources you can implement a AbstractRepositoryEventListener. It allows you to synchronously intercept the actions the Spring Data REST controllers impose on the entities. Use cases to be mentioned here can be additional validation, logging, filtering etc.

Craft your own controller classes

Another way to customize the functionality triggered by a request is through overriding a particular request mapping with a manually implemented controller. This can be used to augment the resources with new functionality (e.g. by exposing a new media type via the produces attribute) or completely replace the functionality by simply declaring a matching request mapping on the controller methods.

Other aspects

Often times the standard resource model is not sufficient to express the domain logic or might just not fit. Users then usually craft their own controllers that they basically blend into the relation space of the resources exposed by Spring Data REST.

To integrate both worlds a ResourceProcessor can be used to add links to the representation to point clients to the manually implemented functionality.

For an example of that, see the Spring RESTBucks project. The core lifecycle of an order is handled by Spring Data REST. However, a core state transition for the order is the triggering of a payment, which is implemented in a separate PaymentController. The payment functionality is then advertised in the order resource using the PaymentOrderResourceProcessor.

Upvotes: 4

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