DynamicService.java

package de.wolff.dsi;

public interface DynamicService {
	
	String invoke();

}

DynamicServiceInvokationApp.java

package de.wolff.dsi;

import javax.ws.rs.ApplicationPath;
import javax.ws.rs.core.Application;

@ApplicationPath("api")
public class DynamicServiceInvokationApp extends Application {

}

DynamicServiceType.java

package de.wolff.dsi;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

import javax.inject.Qualifier;

@Qualifier
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE, ElementType.FIELD, ElementType.METHOD, ElementType.PARAMETER})
public @interface DynamicServiceType {

	String value();
	
}

Endpoint.java

package de.wolff.dsi;

import javax.enterprise.context.ApplicationScoped;
import javax.enterprise.inject.Any;
import javax.enterprise.inject.Instance;
import javax.enterprise.util.AnnotationLiteral;
import javax.inject.Inject;
import javax.json.Json;
import javax.json.JsonObject;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.QueryParam;
import javax.ws.rs.core.MediaType;

@Path("services")
@ApplicationScoped
public class Endpoint {
	
	@Inject
	@Any // This is importent because we want a reference to all implementations
	private Instance<DynamicService> services;
	
	@GET
	@Produces(MediaType.APPLICATION_JSON)
	public JsonObject invokeService(@QueryParam("serviceName") String serviceName) {
		DynamicServiceType serviceType = new DynamicServiceTypeLiteral(serviceName);
		DynamicService service = services.select(serviceType).get();
		return Json.createObjectBuilder().add("result", service.invoke()).build();		
	}
	
	private class DynamicServiceTypeLiteral extends AnnotationLiteral<DynamicServiceType> implements DynamicServiceType {
	
		private static final long serialVersionUID = 6319075567055671586L;
		private final String serviceName;
		
		public DynamicServiceTypeLiteral(String serviceName) {
			this.serviceName = serviceName;
		}

		@Override
		public String value() {
			return serviceName;
		}
		
	}

}

FirstDynamicServiceImpl.java

package de.wolff.dsi;

import javax.enterprise.context.Dependent;

@DynamicServiceType("first")
@Dependent
public class FirstDynamicServiceImpl implements DynamicService{

	@Override
	public String invoke() {
		return "Response first service";
	}

}