Figure out the Meta annotation problem, and introduce 3 new annotations for spring users: @RestateService, @RestateVirtualObject and @RestateWorkflow

Author: slinkydeveloper

sdk-api-gen/src/main/java/dev/restate/sdk/gen/ElementConverter.java

@@ -31,7 +31,7 @@
 import javax.tools.Diagnostic;
 import org.jspecify.annotations.Nullable;
 
-public class ElementConverter {
+class ElementConverter {
 
   private static final PayloadType EMPTY_PAYLOAD =
       new PayloadType(true, "", "Void", "dev.restate.sdk.common.Serde.VOID");
@@ -47,49 +47,29 @@ public ElementConverter(Messager messager, Elements elements, Types types) {
     this.types = types;
   }
 
-  public Service fromTypeElement(TypeElement element) {
+  Service fromTypeElement(MetaRestateAnnotation metaAnnotation, TypeElement element) {
     validateType(element);
 
-    dev.restate.sdk.annotation.Service serviceAnnotation =
-        element.getAnnotation(dev.restate.sdk.annotation.Service.class);
-    dev.restate.sdk.annotation.VirtualObject virtualObjectAnnotation =
-        element.getAnnotation(dev.restate.sdk.annotation.VirtualObject.class);
-    dev.restate.sdk.annotation.Workflow workflowAnnotation =
-        element.getAnnotation(dev.restate.sdk.annotation.Workflow.class);
-    boolean isAnnotatedWithService = serviceAnnotation != null;
-    boolean isAnnotatedWithVirtualObject = virtualObjectAnnotation != null;
-    boolean isAnnotatedWithWorkflow = workflowAnnotation != null;
-
-    // Should be guaranteed by the caller
-    assert isAnnotatedWithWorkflow || isAnnotatedWithVirtualObject || isAnnotatedWithService;
-
-    // Check there's no more than one annotation
-    if (!Boolean.logicalXor(
-        isAnnotatedWithService,
-        Boolean.logicalXor(isAnnotatedWithWorkflow, isAnnotatedWithVirtualObject))) {
-      messager.printMessage(
-          Diagnostic.Kind.ERROR,
-          "The type can be annotated only with one annotation between @VirtualObject, @Workflow and @Service",
-          element);
-    }
-
-    ServiceType type =
-        isAnnotatedWithWorkflow
-            ? ServiceType.WORKFLOW
-            : isAnnotatedWithService ? ServiceType.SERVICE : ServiceType.VIRTUAL_OBJECT;
+    // Find annotation mirror
+    AnnotationMirror metaAnnotationMirror =
+        element.getAnnotationMirrors().stream()
+            .filter(
+                a ->
+                    a.getAnnotationType()
+                        .asElement()
+                        .equals(metaAnnotation.getAnnotationTypeElement()))
+            .findFirst()
+            .orElseThrow(
+                () ->
+                    new IllegalStateException(
+                        "Cannot find the annotation mirror for meta annotation "
+                            + metaAnnotation.getAnnotationTypeElement().getQualifiedName()));
 
     // Infer names
-
     CharSequence targetPkg = elements.getPackageOf(element).getQualifiedName();
     CharSequence targetFqcn = element.getQualifiedName();
-
-    String serviceName =
-        isAnnotatedWithService
-            ? serviceAnnotation.name()
-            : isAnnotatedWithVirtualObject
-                ? virtualObjectAnnotation.name()
-                : workflowAnnotation.name();
-    if (serviceName.isEmpty()) {
+    String serviceName = metaAnnotation.resolveName(metaAnnotationMirror);
+    if (serviceName == null || serviceName.isEmpty()) {
       // Use simple class name, flattening subclasses names
       serviceName =
           targetFqcn.toString().substring(targetPkg.length()).replaceAll(Pattern.quote("."), "");
@@ -105,7 +85,9 @@ public Service fromTypeElement(TypeElement element) {
                         || e.getAnnotation(Workflow.class) != null
                         || e.getAnnotation(Exclusive.class) != null
                         || e.getAnnotation(Shared.class) != null)
-            .map(e -> fromExecutableElement(type, ((ExecutableElement) e)))
+            .map(
+                e ->
+                    fromExecutableElement(metaAnnotation.getServiceType(), ((ExecutableElement) e)))
             .collect(Collectors.toList());
 
     if (handlers.isEmpty()) {
@@ -118,7 +100,7 @@ public Service fromTypeElement(TypeElement element) {
           .withTargetPkg(targetPkg)
           .withTargetFqcn(targetFqcn)
           .withServiceName(serviceName)
-          .withServiceType(type)
+          .withServiceType(metaAnnotation.getServiceType())
           .withHandlers(handlers)
           .validateAndBuild();
     } catch (Exception e) {

sdk-api-gen/src/main/java/dev/restate/sdk/gen/MetaRestateAnnotation.java

@@ -0,0 +1,61 @@
+// Copyright (c) 2023 - Restate Software, Inc., Restate GmbH
+//
+// This file is part of the Restate Java SDK,
+// which is released under the MIT license.
+//
+// You can find a copy of the license in file LICENSE in the root
+// directory of this repository or package, or at
+// https://github.com/restatedev/sdk-java/blob/main/LICENSE
+package dev.restate.sdk.gen;
+
+import dev.restate.sdk.common.ServiceType;
+import java.util.Map;
+import javax.lang.model.element.*;
+import org.jspecify.annotations.Nullable;
+
+class MetaRestateAnnotation {
+
+  private final TypeElement annotation;
+  private final ServiceType serviceType;
+
+  private MetaRestateAnnotation(TypeElement annotation, ServiceType serviceType) {
+    this.annotation = annotation;
+    this.serviceType = serviceType;
+  }
+
+  TypeElement getAnnotationTypeElement() {
+    return annotation;
+  }
+
+  ServiceType getServiceType() {
+    return serviceType;
+  }
+
+  @Nullable String resolveName(AnnotationMirror mirror) {
+    for (Map.Entry<? extends ExecutableElement, ? extends AnnotationValue> entry :
+        mirror.getElementValues().entrySet()) {
+      if (entry.getKey().getSimpleName().contentEquals("name")) {
+        // Got a match, this is the name of the service
+        return (String) entry.getValue().getValue();
+      }
+    }
+    // No name parameter found!
+    return null;
+  }
+
+  static @Nullable MetaRestateAnnotation metaRestateAnnotationOrNull(TypeElement elem) {
+    if (elem.getQualifiedName().toString().equals("dev.restate.sdk.annotation.Service")
+        || elem.getAnnotation(dev.restate.sdk.annotation.Service.class) != null) {
+      return new MetaRestateAnnotation(elem, ServiceType.SERVICE);
+    }
+    if (elem.getQualifiedName().toString().equals("dev.restate.sdk.annotation.VirtualObject")
+        || elem.getAnnotation(dev.restate.sdk.annotation.VirtualObject.class) != null) {
+      return new MetaRestateAnnotation(elem, ServiceType.VIRTUAL_OBJECT);
+    }
+    if (elem.getQualifiedName().toString().equals("dev.restate.sdk.annotation.Workflow")
+        || elem.getAnnotation(dev.restate.sdk.annotation.Workflow.class) != null) {
+      return new MetaRestateAnnotation(elem, ServiceType.WORKFLOW);
+    }
+    return null;
+  }
+}

sdk-api-gen/src/main/java/dev/restate/sdk/gen/ServiceProcessor.java

@@ -27,11 +27,7 @@
 import javax.tools.FileObject;
 import javax.tools.StandardLocation;
 
-@SupportedAnnotationTypes({
-  "dev.restate.sdk.annotation.Service",
-  "dev.restate.sdk.annotation.Workflow",
-  "dev.restate.sdk.annotation.VirtualObject"
-})
+@SupportedAnnotationTypes("*")
 @SupportedSourceVersion(SourceVersion.RELEASE_11)
 public class ServiceProcessor extends AbstractProcessor {
 
@@ -97,9 +93,19 @@ public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment
     // Parsing phase
     List<Map.Entry<Element, Service>> parsedServices =
         annotations.stream()
-            .flatMap(annotation -> roundEnv.getElementsAnnotatedWith(annotation).stream())
-            .filter(e -> e.getKind().isClass() || e.getKind().isInterface())
-            .map(e -> Map.entry((Element) e, converter.fromTypeElement((TypeElement) e)))
+            .map(MetaRestateAnnotation::metaRestateAnnotationOrNull)
+            .filter(Objects::nonNull)
+            .flatMap(
+                metaAnnotation ->
+                    roundEnv
+                        .getElementsAnnotatedWith(metaAnnotation.getAnnotationTypeElement())
+                        .stream()
+                        .filter(e -> e.getKind().isClass() || e.getKind().isInterface())
+                        .map(
+                            e ->
+                                Map.entry(
+                                    (Element) e,
+                                    converter.fromTypeElement(metaAnnotation, (TypeElement) e))))
             .collect(Collectors.toList());
 
     Filer filer = processingEnv.getFiler();

sdk-common/src/main/java/dev/restate/sdk/annotation/Service.java

@@ -8,18 +8,16 @@
 // https://github.com/restatedev/sdk-java/blob/main/LICENSE
 package dev.restate.sdk.annotation;
 
-import java.lang.annotation.ElementType;
-import java.lang.annotation.Retention;
-import java.lang.annotation.RetentionPolicy;
-import java.lang.annotation.Target;
+import java.lang.annotation.*;
 
 /**
  * Annotation to define a class/interface as Restate Service. This triggers the code generation of
  * the related Client class and the {@link
  * dev.restate.sdk.common.syscalls.ServiceDefinitionFactory}.
  */
 @Target(ElementType.TYPE)
-@Retention(RetentionPolicy.SOURCE)
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
 public @interface Service {
   /**
    * Name of the Service for Restate. If not provided, it will be the simple class name of the

sdk-common/src/main/java/dev/restate/sdk/annotation/VirtualObject.java

@@ -8,18 +8,16 @@
 // https://github.com/restatedev/sdk-java/blob/main/LICENSE
 package dev.restate.sdk.annotation;
 
-import java.lang.annotation.ElementType;
-import java.lang.annotation.Retention;
-import java.lang.annotation.RetentionPolicy;
-import java.lang.annotation.Target;
+import java.lang.annotation.*;
 
 /**
  * Annotation to define a class/interface as Restate VirtualObject. This triggers the code
  * generation of the related Client class and the {@link
  * dev.restate.sdk.common.syscalls.ServiceDefinitionFactory}.
  */
 @Target(ElementType.TYPE)
-@Retention(RetentionPolicy.SOURCE)
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
 public @interface VirtualObject {
   /**
    * Name of the VirtualObject for Restate. If not provided, it will be the simple class name of the

sdk-common/src/main/java/dev/restate/sdk/annotation/Workflow.java

@@ -8,10 +8,7 @@
 // https://github.com/restatedev/sdk-java/blob/main/LICENSE
 package dev.restate.sdk.annotation;
 
-import java.lang.annotation.ElementType;
-import java.lang.annotation.Retention;
-import java.lang.annotation.RetentionPolicy;
-import java.lang.annotation.Target;
+import java.lang.annotation.*;
 
 /**
  * Annotation to define a class/interface as Restate Workflow. This triggers the code generation of
@@ -20,7 +17,8 @@
  * workflow, you must annotate one of its methods too as {@link Workflow}.
  */
 @Target({ElementType.METHOD, ElementType.TYPE})
-@Retention(RetentionPolicy.SOURCE)
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
 public @interface Workflow {
   /**
    * Name of the Workflow for Restate. If not provided, it will be the simple class name of the

sdk-spring-boot-starter/src/main/java/dev/restate/sdk/springboot/RestateService.java

@@ -0,0 +1,32 @@
+// Copyright (c) 2023 - Restate Software, Inc., Restate GmbH
+//
+// This file is part of the Restate Java SDK,
+// which is released under the MIT license.
+//
+// You can find a copy of the license in file LICENSE in the root
+// directory of this repository or package, or at
+// https://github.com/restatedev/sdk-java/blob/main/LICENSE
+package dev.restate.sdk.springboot;
+
+import dev.restate.sdk.annotation.Service;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Proxy annotation for {@link Service}, to avoid naming clashes with Spring's built in annotations
+ *
+ * @see Service
+ */
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+@Service
+@RestateComponent
+public @interface RestateService {
+  /**
+   * Name of the Service for Restate. If not provided, it will be the simple class name of the
+   * annotated element.
+   */
+  String name() default "";
+}

sdk-spring-boot-starter/src/main/java/dev/restate/sdk/springboot/RestateVirtualObject.java

@@ -0,0 +1,33 @@
+// Copyright (c) 2023 - Restate Software, Inc., Restate GmbH
+//
+// This file is part of the Restate Java SDK,
+// which is released under the MIT license.
+//
+// You can find a copy of the license in file LICENSE in the root
+// directory of this repository or package, or at
+// https://github.com/restatedev/sdk-java/blob/main/LICENSE
+package dev.restate.sdk.springboot;
+
+import dev.restate.sdk.annotation.Service;
+import dev.restate.sdk.annotation.VirtualObject;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Proxy annotation for {@link VirtualObject}.
+ *
+ * @see Service
+ */
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+@VirtualObject
+@RestateComponent
+public @interface RestateVirtualObject {
+  /**
+   * Name of the VirtualObject for Restate. If not provided, it will be the simple class name of the
+   * annotated element.
+   */
+  String name() default "";
+}

sdk-spring-boot-starter/src/main/java/dev/restate/sdk/springboot/RestateWorkflow.java

@@ -0,0 +1,33 @@
+// Copyright (c) 2023 - Restate Software, Inc., Restate GmbH
+//
+// This file is part of the Restate Java SDK,
+// which is released under the MIT license.
+//
+// You can find a copy of the license in file LICENSE in the root
+// directory of this repository or package, or at
+// https://github.com/restatedev/sdk-java/blob/main/LICENSE
+package dev.restate.sdk.springboot;
+
+import dev.restate.sdk.annotation.Service;
+import dev.restate.sdk.annotation.Workflow;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Proxy annotation for {@link Workflow}.
+ *
+ * @see Service
+ */
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+@Workflow
+@RestateComponent
+public @interface RestateWorkflow {
+  /**
+   * Name of the Workflow for Restate. If not provided, it will be the simple class name of the
+   * annotated element.
+   */
+  String name() default "";
+}

sdk-spring-boot-starter/src/test/java/dev/restate/sdk/springboot/Greeter.java

@@ -10,11 +10,9 @@
 
 import dev.restate.sdk.Context;
 import dev.restate.sdk.annotation.Handler;
-import dev.restate.sdk.annotation.Service;
 import org.springframework.beans.factory.annotation.Value;
 
-@RestateComponent
-@Service
+@RestateService(name = "greeter")
 public class Greeter {
 
   @Value("${greetingPrefix}")