Adds an option to generate spring controllers that return CompletableFutures

README.md

@@ -210,6 +210,7 @@ This section documents the available CLI parameters for controlling what gets ge
 |                               | CHOOSE ANY OF: |
 |                               |   `SUSPEND_MODIFIER` - This option adds the suspend modifier to the generated controller functions |
 |                               |   `AUTHENTICATION` - This option adds the authentication parameter to the generated controller functions |
+|                               |   `COMPLETION_STAGE` - This option makes generated controller functions have Type CompletionStage<T> (works only with Spring Controller generator) |
 |   `--http-controller-target`  | Optionally select the target framework for the controllers that you want to be generated. Defaults to Spring Controllers |
 |                               | CHOOSE ONE OF: |
 |                               |   `SPRING` - Generate for Spring framework. |

src/main/kotlin/com/cjbooms/fabrikt/cli/CodeGenOptions.kt

@@ -53,8 +53,8 @@ enum class ModelCodeGenOptionType(val description: String) {
 
 enum class ControllerCodeGenOptionType(val description: String) {
     SUSPEND_MODIFIER("This option adds the suspend modifier to the generated controller functions"),
-    AUTHENTICATION("This option adds the authentication parameter to the generated controller functions");
-
+    AUTHENTICATION("This option adds the authentication parameter to the generated controller functions"),
+    COMPLETION_STAGE("This option makes generated controller functions have Type CompletionStage<T> (works only with Spring Controller generator)");
     override fun toString() = "`${super.toString()}` - $description"
 }
 

src/main/kotlin/com/cjbooms/fabrikt/generators/controller/SpringControllerInterfaceGenerator.kt

@@ -71,15 +71,24 @@ class SpringControllerInterfaceGenerator(
         val globalSecurity = api.openApi3.securityRequirements.securitySupport()
 
         // Main method builder
-        val funcSpec = FunSpec
+        val baseFunSpec = FunSpec
             .builder(methodName)
             .addModifiers(KModifier.ABSTRACT)
             .addKdoc(op.toKdoc(parameters))
             .addSpringFunAnnotation(op, verb, path.pathString)
             .addSuspendModifier()
-            .returns(SpringImports.RESPONSE_ENTITY.parameterizedBy(returnType))
 
-        parameters
+        val funcSpec = if (options.contains(ControllerCodeGenOptionType.COMPLETION_STAGE)) {
+            baseFunSpec.returns(
+                SpringImports.COMPLETION_STAGE.parameterizedBy(
+                    SpringImports.RESPONSE_ENTITY.parameterizedBy(returnType)
+                )
+            )
+        } else {
+            baseFunSpec.returns(SpringImports.RESPONSE_ENTITY.parameterizedBy(returnType))
+        }
+
+            parameters
             .map {
                 when (it) {
                     is BodyParameter ->

src/main/kotlin/com/cjbooms/fabrikt/generators/controller/metadata/Spring.kt

@@ -19,6 +19,8 @@ object SpringImports {
         const val DATE_TIME_FORMAT = "org.springframework.format.annotation"
 
         const val SPRING_AUTHENTICATION = "$SPRING_BASE.security.core"
+
+        const val JAVA_UTIL_CONCURRENT = "java.util.concurrent"
     }
 
     val CONTROLLER = ClassName(Packages.STEREOTYPE, "Controller")
@@ -41,6 +43,8 @@ object SpringImports {
 
     val AUTHENTICATION = ClassName(Packages.SPRING_AUTHENTICATION, "Authentication")
 
+    val COMPLETION_STAGE = ClassName(Packages.JAVA_UTIL_CONCURRENT, "CompletionStage")
+
     object DateTimeFormat {
         val ISO_DATE = "${DATE_TIME_FORMAT.simpleName}.ISO.DATE"
 

src/test/kotlin/com/cjbooms/fabrikt/generators/SpringControllerGeneratorTest.kt

@@ -239,4 +239,20 @@ class SpringControllerGeneratorTest {
 
         assertThat(controllers.trim()).isEqualTo(expectedControllers.trim())
     }
+
+    @Test
+    fun `controller functions are wrapped by CompletionStage`() {
+        val basePackage = "examples.completionStage"
+        val api = SourceApi(readTextResource("/examples/githubApi/api.yaml"))
+        val expectedControllers = readTextResource("/examples/githubApi/controllers/spring-completion-stage/Controllers.kt")
+
+        val controllers = SpringControllerInterfaceGenerator(
+            Packages(basePackage),
+            api,
+            JavaxValidationAnnotations,
+            setOf(ControllerCodeGenOptionType.COMPLETION_STAGE),
+        ).generate().toSingleFile()
+
+        assertThat(controllers).isEqualTo(expectedControllers)
+    }
 }