Spring MVC - How can I dynamically switch the implementing class? - spring

Question

My question is about finding the best technique for implementing a bean switcher for managing different sites with different persistent layers.
I designed a server for Customer management and e-eCommerce services.
For each service I am using an API layer, a Controller layer and a persistent layer.
This server is managing multiple sites for different clients.
Up until today, all my sites have used the same persistent layer for all the sites.
Recently, I have a new request for integrating the customers services from an outside server - In other words, Integration with external service.
I am trying to solve this by adding another persistent layer that uses the external service's API, and when I get request from this site, to switch the persistent layer to the outside service (Like a factory).
Lets assume I have details about the site which the request came from....
My goal is to use a kind of 'Factory' for switching between the persistent layers according to the parameters that I pull from the request.
How do I dynamically switch the implementing class of the interface using the Spring MVC tools?
I found this solution: https://www.baeldung.com/spring-dynamic-autowire, but I don't think it is the best solution.
Can anyone share a different technique to achieve my goal?
Thank you so much for any help!!!
Asaf

Answer 1

You can use Factory pattern to solve this issue.
You can define a class that will autowired all types of data services. You should first define an abstraction via interface something like this.
interface SomeDao {
...
}
#Service(name="someDaoMysql")
class SomeDaoMysqlImpl implements SomeDao {
...
}
#Service(name="someDaoApi")
class SomeDaoApiImpl implement SomeDao {
...
}
Once you have these different variants of the SomeDao interface, return one of them based on some parameters. A factory interface might look like this.
enum DaoType{
API,
MYSQL;
}
interface SomeDaoFactory {
SomeDao getDao( DaoType type);
}
#Component
class SomeDaoFactoryImpl implements SomeDaoFactory{
#Aurowired #Qualifier("someDaoMysql") SomeDao someDaoMysql;
#Aurowired #Qualifier("someDaoApi") SomeDao someDaoApi;
public SomeDao getDao( DaoType type){
switch(type){
case API:
return someDaoApi;
case MYSQL:
return someDaoMysql;
default:
throw new IllegalStateExecption("Unknown type"+type);
}
}
Usage
#Service
public class SomeFancyServiceImpl implements SomeFancyService{
#Autowired SomeDaoFactory someDaoFactory;
#Override
public void doSomething(){
SomeDao dao = someDaoFactory.getDao( API );
// do something with dao
}
}