Allow subclasses to be considered as services.

services-api/src/main/java/io/scalecube/services/Reflect.java

@@ -18,11 +18,13 @@
 import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
 import java.util.Arrays;
-import java.util.Collection;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.Map;
+import java.util.Set;
 import java.util.function.Function;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 import org.reactivestreams.Publisher;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
@@ -255,11 +257,15 @@ public static Map<String, Method> serviceMethods(Class<?> serviceInterface) {
    * @param serviceObject with extends service interface with @Service annotation.
    * @return service interface class.
    */
-  public static Collection<Class<?>> serviceInterfaces(Object serviceObject) {
-    Class<?>[] interfaces = serviceObject.getClass().getInterfaces();
-    return Arrays.stream(interfaces)
-        .filter(interfaceClass -> interfaceClass.isAnnotationPresent(Service.class))
-        .collect(Collectors.toList());
+  public static Stream<Class<?>> serviceInterfaces(Object serviceObject) {
+    Class<?> current = serviceObject.getClass();
+    Set<Class<?>> interfaces = new HashSet<>();
+    while (current != Object.class) {
+      interfaces.addAll(Arrays.asList(current.getInterfaces()));
+      current = current.getSuperclass();
+    }
+    return interfaces.stream()
+        .filter(interfaceClass -> interfaceClass.isAnnotationPresent(Service.class));
   }
 
   public static String methodName(Method method) {

services-api/src/main/java/io/scalecube/services/ServiceScanner.java

@@ -1,6 +1,5 @@
 package io.scalecube.services;
 
-import io.scalecube.services.annotations.Service;
 import io.scalecube.services.annotations.ServiceMethod;
 import java.util.Arrays;
 import java.util.Collections;
@@ -22,8 +21,7 @@ private ServiceScanner() {
    * @return list of {@code ServiceRegistration}-s
    */
   public static List<ServiceRegistration> scanServiceInfo(ServiceInfo serviceInfo) {
-    return Arrays.stream(serviceInfo.serviceInstance().getClass().getInterfaces())
-        .filter(serviceInterface -> serviceInterface.isAnnotationPresent(Service.class))
+    return Reflect.serviceInterfaces(serviceInfo.serviceInstance())
         .map(
             serviceInterface -> {
               Map<String, String> serviceInfoTags = serviceInfo.tags();

services-api/src/test/java/io/scalecube/services/methods/ReflectTest.java

@@ -7,11 +7,13 @@
 
 import io.scalecube.services.CommunicationMode;
 import io.scalecube.services.Reflect;
+import io.scalecube.services.annotations.Service;
 import io.scalecube.services.api.ServiceMessage;
 import java.lang.reflect.Method;
 import java.util.Arrays;
 import java.util.stream.Stream;
 import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
@@ -108,4 +110,31 @@ private interface TestService {
 
     Flux<ServiceMessage> requestChannelMessage(Flux<ServiceMessage> sm);
   }
+
+  @Service
+  private interface SimpleService {
+    public String name();
+  }
+
+  private class ServiceImpl implements SimpleService {
+    @Override
+    public String name() {
+      return "duke";
+    }
+  }
+
+  private class SubServiceImpl extends ServiceImpl {
+
+  }
+
+  @Test
+  public void testSubServiceInterfaces() {
+
+    // When:
+    Stream<Class<?>> interfaces = Reflect.serviceInterfaces(new SubServiceImpl());
+    // Then:
+    Assertions.assertEquals(
+        1,
+        interfaces.count(), "serviceInterfaces(..) should detect interfaces in SubServiceImpl");
+  }
 }