Issue
In my project I have different services. Each service can define its own Permissions. For each permission, a bean will created. This way, the Authorization service can inject all available permission, without actually knowing them.
The Permission definition of ServiceA will look like this:
@Configuration()
public class ServiceAPermissions extends Permissions {
private static final String BASE = "servicea";
public static final String SERVICEA_READ = join(BASE, READ);
public static final String SERVICEA_WRITE = join(BASE, WRITE);
@Bean()
Permission getReadPermission() {
return new Permission(SERVICEA_READ);
}
@Bean()
Permission getWritePermission() {
return new Permission(SERVICEA_WRITE);
}
}
ServiceB will define the following Permissions:
@Configuration()
public class ServiceBPermissions extends Permissions {
private static final String BASE = "serviceb";
public static final String SERVICEB_READ = join(BASE, READ);
@Bean()
Permission getReadPermission() {
return new Permission(SERVICEB_READ);
}
}
Obviously, this will end in a name clash of the defined beans as I have defined a bean with the name getReadPermission twice. If course I can name the methods like getServiceAReadPermission so they will be distinguished, but this only a convention, which might be ignored.
In this situation, Spring doesn't notify me about the duplicate definition, it simply will just instantiate one and ignore the other definition. Is there a way to tell Spring to throw an Exception, if a bean is defined twice? This way one would be always aware of a duplicate definition.
Alternatively, is there a way to tell spring, that it should use a random bean name instead of the method signature? I know that I can give each bean a name manually @Bean(name = "A name"), but I like to avoid that, as a dev will not be forced to do so and still might forget it.
Solution
That design does not seem very logical. A bean is supposed to be available only once, you're using it differently.
I'd suggest to provide a PermissionFactory-Bean which does what you need, along the line of
@Component
public class PermissionFactory {
public Permission createFactory() {
// create A or B permission randomly, as you wanted
}
}
Answered By - daniu
