Add a super simple controller for listing and storing new registrations

Be aware: This is a HTTP/JSON based API but not a REST api ;) Use Spring Data REST for easy creation of such apis.

src/main/java/ac/simons/netbeansevening/RegistrationController.java

@@ -0,0 +1,37 @@
+package ac.simons.netbeansevening;
+
+import javax.validation.Valid;
+
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import static org.springframework.web.bind.annotation.RequestMethod.GET;
+import static org.springframework.web.bind.annotation.RequestMethod.POST;
+
+@RestController
+@RequestMapping("/registrations")
+public class RegistrationController {
+
+    private final RegistrationRepository registrationRepository;
+
+    public RegistrationController(RegistrationRepository registrationRepository) {
+	this.registrationRepository = registrationRepository;
+    }
+
+    @RequestMapping(method = GET)
+    public Iterable<RegistrationEntity> list() {
+	return this.registrationRepository.findAll();
+    }
+
+    @RequestMapping(value = "/{id}", method = GET)
+    public RegistrationEntity get(@PathVariable Integer id) {
+	return this.registrationRepository.findOne(id);
+    }
+
+    @RequestMapping(method = POST)
+    public RegistrationEntity create(@Valid @RequestBody RegistrationEntity newRegistration) {
+	return this.registrationRepository.save(newRegistration);
+    }
+}