How to create custom Cache in Spring AOP

Question

I am new to Spring AOP, and was reading how to create annotations.

I want to create a custom cache handler which would create a Cache for the particular request only.

I can inherit from HandlerInterceptorAdapter to create and clear the in memory cache.

and can use a ContextHolder for to store.

like

@NoArgsConstructor(access = AccessLevel.PRIVATE)
public final class CachedContextHolder {

  private static final ThreadLocal<GenericContext> CONTEXT_HOLDER = new ThreadLocal<>();

  @Data
  public static class GenericContext {

    private AppEventHandlerPayload payload = new AppEventHandlerPayload();

    private HashMap<String, Object> cache = new HashMap<String, Object>;
  }

and store data in this particular context.

What I want to do is create a @cacheable annotation where I can intercept the method and if its available in cache return from there otherwise read from DB.

I was reading this https://www.baeldung.com/spring-aop-annotation

But not sure how to do this?

• joinPoint.proceed(); would execute the method but how do I get the params? couldnt see any methods here https://www.eclipse.org/aspectj/doc/released/runtime-api/org/aspectj/lang/JoinPoint.html

I am new to Spring AOP, and couldn't find a proper fleshed out example anywhere. Any help would be great.

Answer 1

If you want to get the arguments you can use joinPoint.getArgs() https://www.eclipse.org/aspectj/doc/released/runtime-api/org/aspectj/lang/JoinPoint.html#getArgs().

Instead of creating your own implementation, I recommend using The Cache Abstraction from Spring: https://docs.spring.io/spring-framework/docs/current/reference/html/integration.html#cache and a cache provider like Caffeine or EhCache.