Question

My application has a interface as below.

public interface MainInterface
{
     void someMethod();
}

Then, i have number of implementations of this interface.

@Service    
public class ImplClass1 implements MainInterface
{
   @Override
   public void someMehtod()
   {
      //Execution of code
   }
}

@Service    
public class ImplClass2 implements MainInterface
{
   @Override
   public void someMehtod()
   {
      //Execution of code
   }
}

@Service
public class ImplClass3 implements MainInterface
{
   @Override
   public void someMehtod()
   {
      //Execution of code
   }
}

Below is a controller.

@Controller
public class MainController
{
     MainInterface implObj;

     @RequestMapping("service1")
     public void Service1Handler()
     {
         //Replace below with @Autowire
         implObj = new ImplClass1();
     }

     @RequestMapping("service2")
     public void Service1Handler()
     {
         //Replace below with @Autowire
         implObj = new ImplClass2();
     }

     @RequestMapping("service3")
     public void Service1Handler()
     {
         //Replace below with @Autowire
         implObj = new ImplClass3();
     }
}

As mentioned in comment of each method i want to initialize it using spring.
This is just an example. In my real time application i have 12 implementations of a interface and 6 methods in a controller.

Can you please guide how can i use autowire feature at method level or suggest any other best way around.

Thanks

Answer 1

Can think of these two ways –

@Controller
public class MainController
{
     @Autowired @Qualifier("impl1") MainInterface impl1;
     @Autowired @Qualifier("impl2") MainInterface impl2;
     @Autowired @Qualifier("impl3") MainInterface impl3;

     @RequestMapping("service1")
     public void service1Handler()
     {
          impl1.doSomething()
     }

     @RequestMapping("service2")
     public void Service1Handler()
     {
         //Replace below with @Autowire
          impl2.doSomething()
     }

     @RequestMapping("service3")
     public void Service1Handler()
     {
         //Replace below with @Autowire
           impl3.doSomething()
     }
}

OR hide it behind a factory:

class MaintenanceInterfaceFactory{
     @Autowired @Qualifier("impl1") MainInterface impl1;
     @Autowired @Qualifier("impl2") MainInterface impl2;
     @Autowired @Qualifier("impl3") MainInterface impl3;
     getImplForService(String name){
        //return one of the impls above based on say service name..
     }
}