Recently our team needed to measure the performance of a client’s application, which heavily depends on third API providers, such as Spotify, Yelp and TripAdvisor. Our goal was to mock the response from these providers in an easy way, which will later help us to measure the performance of the code base without concerning the response time from the third party APIs.My immediate enlightenment was to get advantage of the Aspect Oriented Programming with the spring aop project. The idea is to intercept the calls to the external providers and execute a custom method which will fake their response.
As usual this tutorial can be completed step by step or you can directly clone a simple demo project from https://github.com/boykodimitroff/aspectj-demo
The provided git project is a basic Spring Boot application with included Spring AOP dependency.
Let’s take a look of the following class
eu.dreamix.rest.RestController.java
package eu.dreamix.rest;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
/**
* Created by bdimitrov on 6/6/17.
*/
@RestController
@RequestMapping("/rest/")
public class SpotifyController {
@RequestMapping(value = "/spotify", method = RequestMethod.GET)
public ResponseEntity
As I mentioned at the beginning we are going to mock an existing functionality, so SpotifyController.java is just a basic rest controller with one method, the returned object of which will be mocked.
The meaningful work unit regarding our task is in the following class
eu.dreamix.aspect.SpotifyAspect.java
package eu.dreamix.aspect;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.ResponseEntity;
/**
* Created by bdimitrov on 6/6/17.
*/
@Aspect
@Configuration
public class SpotifyAspect {
@Pointcut("execution(* eu.dreamix.rest.SpotifyController.callSpotify(..))")
public void inSpotifyController() {}
@Around("inSpotifyController()")
public ResponseEntity mockSpotify() {
return ResponseEntity.ok("Mocked Spotify call");
}
}
Three terms needs clarification here. Aspect, advice and pointcut.
