Dada una interfaz IService
, y 3 implementaciones de la misma: ServiceA
, ServiceALogger
y ServiceAMetrics
.
ServiceALogger
y ServiceAMetrics
son las envolturas de la ServiceA
y serán instanciados opcionalmente. Además, hay una combinación en la que ServiceAMetrics
y ServiceALogger
tanto instanciado.
Sé cómo hacerlo operativo @Configuration
y el @Bean
método, pero ¿es posible implementar el uso de anotaciones de clase ( @Primary
, @Order
...)?
Aquí hay un fragmento de demostrar un concepto:
package com.foo;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Condition;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.context.annotation.Conditional;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.type.AnnotatedTypeMetadata;
import org.springframework.stereotype.Service;
interface IService {
void foo();
}
class LoggerCondition implements Condition {
@Override
public boolean matches(ConditionContext conditionContext, AnnotatedTypeMetadata annotatedTypeMetadata) {
return false;
}
}
class MetricsCondition implements Condition {
@Override
public boolean matches(ConditionContext conditionContext, AnnotatedTypeMetadata annotatedTypeMetadata) {
return false;
}
}
@Service
class ServiceA implements IService {
@Override
public void foo() {
System.out.println("I'm foo");
}
}
@Service
@Conditional(LoggerCondition.class)
class ServiceALogger implements IService {
private final IService service;
public ServiceALogger(IService service) {
this.service = service;
}
@Override
public void foo() {
System.out.println("print some logs");
service.foo();
}
}
@Service
@Conditional(MetricsCondition.class)
class ServiceAMetrics implements IService {
private final IService service;
public ServiceAMetrics(IService service) {
this.service = service;
}
@Override
public void foo() {
System.out.println("send some metrics");
service.foo();
}
}
@Configuration
@ComponentScan("com.foo")
public class Main {
public static void main(String[] args) {
AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
ctx.register(Main.class);
ctx.refresh();
IService bean = ctx.getBean(IService.class);
bean.foo();
}
}
Parece que encontré una posible solución. No es un elegante, pero funciona.
Utilizo @Priority
anotaciones para determinar qué bean debe inyectarse cuando hay varios casos de ellos. Y @Qualifier
para romper una dependencia circular entre ServiceAMetrics
y ServiceALogger
.
package com.foo;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Condition;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.context.annotation.Conditional;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.type.AnnotatedTypeMetadata;
import org.springframework.stereotype.Service;
import javax.annotation.Priority;
import java.util.List;
interface IService {
void foo();
}
class LoggerCondition implements Condition {
@Override
public boolean matches(ConditionContext conditionContext, AnnotatedTypeMetadata annotatedTypeMetadata) {
return true;
}
}
class MetricsCondition implements Condition {
@Override
public boolean matches(ConditionContext conditionContext, AnnotatedTypeMetadata annotatedTypeMetadata) {
return true;
}
}
@Service
@Qualifier("main")
@Priority(Integer.MAX_VALUE)
class ServiceA implements IService {
@Override
public void foo() {
System.out.println("I'm foo");
}
}
@Service
@Conditional(LoggerCondition.class)
@Priority(Integer.MAX_VALUE - 1)
class ServiceALogger implements IService {
private final IService service;
// using this @Qualifier prevents circular dependency
public ServiceALogger(@Qualifier("main") IService service) {
this.service = service;
}
@Override
public void foo() {
System.out.println("print some logs");
service.foo();
}
}
@Service
@Conditional(MetricsCondition.class)
@Priority(Integer.MAX_VALUE - 2)
class ServiceAMetrics implements IService {
private final IService service;
public ServiceAMetrics(IService service) {
this.service = service;
}
@Override
public void foo() {
System.out.println("send some metrics");
service.foo();
}
}
@Configuration
@ComponentScan("com.foo")
public class Main {
public static void main(String[] args) {
AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
ctx.register(Main.class);
ctx.refresh();
IService bean = ctx.getBean(IService.class);
bean.foo();
}
}