programmatic client generation for MP Rest Client, fixes #1317

docs/src/main/asciidoc/rest-client-guide.adoc

@@ -157,7 +157,8 @@ The `getByName` method gives our code the ability to query a country by name fro
 
 The purpose of the annotations in the code above is the following:
 
-* `@RegisterRestClient` allows {project-name} to know that this interface is meant to be used as a REST Client
+* `@RegisterRestClient` allows {project-name} to know that this interface is meant to be available for
+CDI injection as a REST Client
 * `@Path`, `@GET` and `@PathParam` are the standard JAX-RS annotations used to define how to access the service
 * `@Produces` defines the expected content-type
 
@@ -268,3 +269,7 @@ You should see a JSON object containing some basic information about Greece.
 
 As usual, the application can be packaged using `mvn clean package` and executed using the `-runner.jar` file.
 You can also generate the native executable with `mvn clean package -Pnative`.
+
+== Further reading
+
+ * link:https://download.eclipse.org/microprofile/microprofile-rest-client-1.2.1/microprofile-rest-client-1.2.1.html[MicroProfile Rest Client specification]

extensions/smallrye-rest-client/deployment/src/main/java/io/quarkus/smallrye/restclient/deployment/SmallRyeRestClientProcessor.java

@@ -22,18 +22,19 @@
 import java.util.Map;
 import java.util.Set;
 
+import javax.ws.rs.Path;
 import javax.ws.rs.client.ClientRequestFilter;
 import javax.ws.rs.client.ClientResponseFilter;
 import javax.ws.rs.ext.Providers;
 
 import org.apache.commons.logging.impl.Jdk14Logger;
 import org.apache.commons.logging.impl.LogFactoryImpl;
-import org.eclipse.microprofile.rest.client.inject.RegisterRestClient;
 import org.eclipse.microprofile.rest.client.inject.RestClient;
 import org.jboss.jandex.AnnotationInstance;
 import org.jboss.jandex.AnnotationTarget;
 import org.jboss.jandex.ClassInfo;
 import org.jboss.jandex.DotName;
+import org.jboss.jandex.IndexView;
 import org.jboss.jandex.MethodInfo;
 import org.jboss.jandex.Type;
 import org.jboss.resteasy.client.jaxrs.ResteasyClientBuilder;
@@ -47,7 +48,6 @@
 import io.quarkus.arc.processor.BeanConfigurator;
 import io.quarkus.arc.processor.BeanRegistrar;
 import io.quarkus.arc.processor.BuiltinScope;
-import io.quarkus.arc.processor.ScopeInfo;
 import io.quarkus.deployment.annotations.BuildProducer;
 import io.quarkus.deployment.annotations.BuildStep;
 import io.quarkus.deployment.annotations.ExecutionTime;
@@ -73,7 +73,7 @@ class SmallRyeRestClientProcessor {
 
     private static final DotName REST_CLIENT = DotName.createSimple(RestClient.class.getName());
 
-    private static final DotName REGISTER_REST_CLIENT = DotName.createSimple(RegisterRestClient.class.getName());
+    private static final DotName PATH = DotName.createSimple(Path.class.getName());
 
     private static final String PROVIDERS_SERVICE_FILE = "META-INF/services/" + Providers.class.getName();
 
@@ -141,7 +141,8 @@ void processInterfaces(CombinedIndexBuildItem combinedIndexBuildItem,
         Map<DotName, ClassInfo> interfaces = new HashMap<>();
         Set<Type> returnTypes = new HashSet<>();
 
-        for (AnnotationInstance annotation : combinedIndexBuildItem.getIndex().getAnnotations(REGISTER_REST_CLIENT)) {
+        IndexView index = combinedIndexBuildItem.getIndex();
+        for (AnnotationInstance annotation : index.getAnnotations(PATH)) {
             AnnotationTarget target = annotation.target();
             ClassInfo theInfo;
             if (target.kind() == AnnotationTarget.Kind.CLASS) {
@@ -151,9 +152,11 @@ void processInterfaces(CombinedIndexBuildItem combinedIndexBuildItem,
             } else {
                 continue;
             }
-            if (!Modifier.isInterface(theInfo.flags())) {
+
+            if (!isRestClientInterface(index, theInfo)) {
                 continue;
             }
+
             interfaces.put(theInfo.name(), theInfo);
 
             // Find Return types
@@ -212,4 +215,9 @@ public void register(RegistrationContext registrationContext) {
         extensionSslNativeSupport.produce(new ExtensionSslNativeSupportBuildItem(FeatureBuildItem.SMALLRYE_REST_CLIENT));
         RestClientBuilderImpl.SSL_ENABLED = sslNativeConfig.isEnabled();
     }
+
+    private boolean isRestClientInterface(IndexView index, ClassInfo classInfo) {
+        return Modifier.isInterface(classInfo.flags())
+                && index.getAllKnownImplementors(classInfo.name()).isEmpty();
+    }
 }

integration-tests/main/src/main/java/io/quarkus/example/rest/ClientResource.java

@@ -37,9 +37,9 @@ public class ClientResource {
     @GET
     @Path("/manual")
     public String manual() throws Exception {
-        RestInterface iface = RestClientBuilder.newBuilder()
+        ProgrammaticRestInterface iface = RestClientBuilder.newBuilder()
                 .baseUrl(new URL(System.getProperty("test.url")))
-                .build(RestInterface.class);
+                .build(ProgrammaticRestInterface.class);
         return iface.get();
     }
 
@@ -53,9 +53,9 @@ public String cdi() throws Exception {
     @Path("manual/jackson")
     @Produces("application/json")
     public TestResource.MyData getDataManual() throws Exception {
-        RestInterface iface = RestClientBuilder.newBuilder()
+        ProgrammaticRestInterface iface = RestClientBuilder.newBuilder()
                 .baseUrl(new URL(System.getProperty("test.url")))
-                .build(RestInterface.class);
+                .build(ProgrammaticRestInterface.class);
         System.out.println(iface.getData());
         return iface.getData();
     }
@@ -71,9 +71,9 @@ public TestResource.MyData getDataCdi() {
     @Path("/manual/complex")
     @Produces("application/json")
     public List<ComponentType> complexManual() throws Exception {
-        RestInterface iface = RestClientBuilder.newBuilder()
+        ProgrammaticRestInterface iface = RestClientBuilder.newBuilder()
                 .baseUrl(new URL(System.getProperty("test.url")))
-                .build(RestInterface.class);
+                .build(ProgrammaticRestInterface.class);
         System.out.println(iface.complex());
         return iface.complex();
     }

integration-tests/main/src/main/java/io/quarkus/example/rest/ProgrammaticRestInterface.java

@@ -0,0 +1,28 @@
+package io.quarkus.example.rest;
+
+import java.util.List;
+
+import javax.ws.rs.GET;
+import javax.ws.rs.Path;
+import javax.ws.rs.Produces;
+
+/**
+ * A version of {@link RestInterface} that doesn't have {@link org.eclipse.microprofile.rest.client.inject.RegisterRestClient}
+ * and can be used only programmatically, i.e. with the builder.
+ */
+@Path("/test")
+public interface ProgrammaticRestInterface {
+
+    @GET
+    String get();
+
+    @GET
+    @Path("/jackson")
+    @Produces("application/json")
+    TestResource.MyData getData();
+
+    @GET
+    @Path("/complex")
+    @Produces("application/json")
+    List<ComponentType> complex();
+}