Batch loading of providers

[charphi]

Add the possibility to load a bach of providers.

Example:

public interface HelloService {}

@ServiceProvider
public class Impl1 implements HelloService {}

@ServiceProvider
public class Impl2 implements HelloService {}

public class SomeClass {
  @ServiceProviderList
  public Collection<? extends HelloService> getProviders() { ... }
}

[charphi]

Here is another way of doing it:

Add a property @ServiceDefinition#batch to generate a *Batch interface alongside the *Loader class.
This new *Batch interface can be implemented by providers and their implementations are loaded with the normal providers.

@ServiceDefinition ( batch = true )
public interface HelloService { }

@ServiceProvider
public class NormalHelloProvider implements HelloService { }

@ServiceProvider
public class BatchHelloProvider implements HelloServiceBatch {
    @Override
    public Stream<HelloService> getProviders() { ... }
}

[charphi]

Use cases:

• create a bridge between two service definitions
• generate providers on the fly

[charphi]

Done in 11f9202