factory pattern using spring - spring

Question

How can I choose a service implementation depending on a request parameter on SpringBoot? I can do this by manually instantiating the service, but that's not making use of the Spring Injection feature.
I can also Autowire the two services separately but I'm thinking that if I have more implementations that would pollute the class.
Here's a crude example:
#RestController
class RestControllerTest {
#Autowired
PizzaService pizzaService;
public void bakePizza(#RequestParam("type") String type,#RequestParam("extra") String extra) {
if (type.equals("cheese")) {
//set pizzaService Cheese Implementation
pizzaService = new CheezePizza();
} else {
//set PizzaService vegetable Impleentation;
pizzaService = new VegetablePizza();
}
pizzaService.prepareIngredients(extra);
pizzaService.bakePizza();
}
}
public abstract class PizzaService {
String ingredients;
public abstract void prepareIngredients(String exraIngredient);
public void bakePizza() {
System.out.println("baking pizza with " + ingredients);
}
}
class CheezePizza extends PizzaService {
#Override
public void prepareIngredients(String exraIngredient) {
ingredients = "Cheese " + exraIngredient;
}
}
class VegetablePizza extends PizzaService {
#Override
public void prepareIngredients(String exraIngredient) {
ingredients = "Vegetable " + exraIngredient;
}
}

Answer 1

You could autowire list of beans of same type. So let's say you add getType() to your PizzaService and register every type as spring bean.
public abstract class PizzaService {
abstract String getType();
}
#Component
class CheezePizza extends PizzaService {
#Override
public String getType() {
return "cheese";
}
}
#Component
class VegetablePizza extends PizzaService {
#Override
public String getType() {
return "vegetable";
}
}
#RestController
class RestControllerTest {
private final Map<String, PizzaService> pizzaServices;
public RestControllerTest(List<PizzaService> services) {
pizzaServices = services.stream().collect(Collectors.toMap(PizzaService::getType, Function.identity()));
}
public void bakePizza(#RequestParam("type") String type, #RequestParam("extra") String extra) {
PizzaService pizzaService = pizzaServices.get(type); // remember of handling missing type
pizzaService.prepareIngredients(extra);
pizzaService.bakePizza();
}
}
Another way is to use name your beans by convention i.e. cheesePizza, vegetablePizza and then use ApplicationContext#getBean(type + "Pizza") but I like first approach better, because it's less magical.