Where to put @Cacheable annotation

Question

What is the best practice on where to put @Cacheable annotation. Should it be in Interface (Myservice) or in the implementation (MyserviceImpl) class.

  public class MyClass
  {
  
    public final Map<String, String> getDepartmentsList(String userid) {
        System.out.println("I am getting the dept" );
        Map<String, String> deptMap = myService.getList(userid);
        return deptMap;
    }
 }



  @Service 
    public class MyserviceImpl implements Myservice  
    {
    ****@Cacheable(cacheName = "myList", keyGeneratorName = "cacheKeyGenerator" )****
        public Map<String, String> getList(String userid){
        }
    }
  

public interface Myservice  {

     **@Cacheable(cacheName = "myList", keyGeneratorName = "cacheKeyGenerator" )**
     public Map<String, String> getList(String userid);
    }

Answer 1

There is no silver bullet. It depends on your purposes. If you declare it on the interface you declare: all implementations have a cached method. But probably in most cases, you can hide these details from your API/SPI user in a specific implementation.