build: enforce google-java-format with a spotless check gate

pom.xml

@@ -168,6 +168,29 @@
                     </execution>
                 </executions>
             </plugin>
+            <plugin>
+                <groupId>com.diffplug.spotless</groupId>
+                <artifactId>spotless-maven-plugin</artifactId>
+                <version>2.46.1</version>
+                <configuration>
+                    <java>
+                        <googleJavaFormat>
+                            <version>1.22.0</version>
+                            <style>GOOGLE</style>
+                        </googleJavaFormat>
+                        <removeUnusedImports/>
+                    </java>
+                </configuration>
+                <executions>
+                    <execution>
+                        <id>spotless-check</id>
+                        <phase>validate</phase>
+                        <goals>
+                            <goal>check</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
             <plugin>
                 <groupId>org.codehaus.mojo</groupId>
                 <artifactId>flatten-maven-plugin</artifactId>

samples/pom.xml

@@ -76,6 +76,8 @@
 
     <properties>
         <maven.deploy.skip>true</maven.deploy.skip>
+        <!-- Demo module: formatting gate applies to the published modules only. -->
+        <spotless.skip>true</spotless.skip>
     </properties>
 
     <build>

spring-boot-starter/src/main/java/dev/openan/workflow/engine/spring/A2AAutoConfiguration.java

@@ -65,8 +65,8 @@
  *   <li>{@link RequestHandler} - the {@link DefaultRequestHandler}
  *   <li>{@link RestHandler} - the REST protocol handler
  *   <li>{@link MainEventBusProcessor} - the event bus
- *   <li>{@link A2AController} - the Spring MVC controller (message send/stream plus task
- *       query, list, cancel, and subscribe endpoints)
+ *   <li>{@link A2AController} - the Spring MVC controller (message send/stream plus task query,
+ *       list, cancel, and subscribe endpoints)
  *   <li>Optional slash-style aliases for gateways that cannot publish colon-style action paths
  * </ul>
  *
@@ -217,14 +217,12 @@ public A2AController a2aController(
   }
 
   /**
-   * Adds non-standard slash-style action aliases without changing the canonical A2A endpoints.
-   * This compatibility surface is disabled unless explicitly enabled for a constrained gateway.
+   * Adds non-standard slash-style action aliases without changing the canonical A2A endpoints. This
+   * compatibility surface is disabled unless explicitly enabled for a constrained gateway.
    */
   @Bean
   @ConditionalOnMissingBean(A2ASlashActionAliasController.class)
-  @ConditionalOnProperty(
-      name = "a2at.server.slash-action-aliases-enabled",
-      havingValue = "true")
+  @ConditionalOnProperty(name = "a2at.server.slash-action-aliases-enabled", havingValue = "true")
   A2ASlashActionAliasController a2aSlashActionAliasController(A2AController delegate) {
     return new A2ASlashActionAliasController(delegate);
   }

spring-boot-starter/src/main/java/dev/openan/workflow/engine/spring/A2AController.java

@@ -172,7 +172,8 @@ private SseEmitter subscribeToEmitter(
             try {
               context.invokeEventConsumerCancelCallback();
             } catch (RuntimeException error) {
-              log.warn("[SSE] Failed to notify SDK event consumer cancellation: {}", error.getMessage());
+              log.warn(
+                  "[SSE] Failed to notify SDK event consumer cancellation: {}", error.getMessage());
             }
           }
         };
@@ -278,14 +279,14 @@ public ResponseEntity<String> cancelTask(
   @PostMapping(
       value = "${a2at.server.path-prefix}/tasks/{id}:subscribe",
       produces = MediaType.TEXT_EVENT_STREAM_VALUE)
-  public SseEmitter subscribeToTask(
-      HttpServletRequest req, @PathVariable("id") String taskId) {
+  public SseEmitter subscribeToTask(HttpServletRequest req, @PathVariable("id") String taskId) {
     try {
       var ctx = buildContext(req);
       requireStreamingSupport();
       requestHandler.authorizeTaskAccess(taskId, ctx, TaskOperation.SUBSCRIBE_TO_TASK);
       Flow.Publisher<StreamingEventKind> publisher =
-          requestHandler.onSubscribeToTask(TaskIdParams.builder().id(taskId).tenant("").build(), ctx);
+          requestHandler.onSubscribeToTask(
+              TaskIdParams.builder().id(taskId).tenant("").build(), ctx);
       return subscribeToEmitter(publisher, ctx);
     } catch (A2AError e) {
       log.warn("[SSE] Task subscription rejected before stream creation: {}", e.getMessage());

spring-boot-starter/src/main/java/dev/openan/workflow/engine/spring/A2AProperties.java

@@ -40,8 +40,8 @@ public class A2AProperties {
   private String pathPrefix = "/a2a/json";
 
   /**
-   * Whether to expose slash-style aliases for A2A action endpoints for gateways that reject
-   * colons in published paths. Standard colon-style endpoints always remain available.
+   * Whether to expose slash-style aliases for A2A action endpoints for gateways that reject colons
+   * in published paths. Standard colon-style endpoints always remain available.
    */
   private boolean slashActionAliasesEnabled = false;
 

spring-boot-starter/src/main/java/dev/openan/workflow/engine/spring/A2ASlashActionAliasController.java

@@ -30,8 +30,8 @@
 /**
  * Optional slash-style aliases for A2A action endpoints.
  *
- * <p>Every operation delegates to {@link A2AController}; the aliases therefore retain the
- * canonical endpoint's authentication, A2A error envelope, streaming, and cleanup behavior.
+ * <p>Every operation delegates to {@link A2AController}; the aliases therefore retain the canonical
+ * endpoint's authentication, A2A error envelope, streaming, and cleanup behavior.
  */
 @RestController
 @ConditionalOnProperty(

spring-boot-starter/src/test/java/dev/openan/workflow/engine/spring/A2AAutoConfigurationTest.java

@@ -18,6 +18,7 @@
  */
 package dev.openan.workflow.engine.spring;
 
+import static org.hamcrest.Matchers.containsString;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertThrows;
@@ -29,12 +30,11 @@
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyNoInteractions;
 import static org.mockito.Mockito.when;
-import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
 import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.asyncDispatch;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.request;
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
-import static org.hamcrest.Matchers.containsString;
 
 import java.lang.reflect.Modifier;
 import java.util.concurrent.ExecutorService;
@@ -49,13 +49,12 @@
 import org.a2aproject.sdk.server.requesthandlers.RequestHandler;
 import org.a2aproject.sdk.spec.AgentCapabilities;
 import org.a2aproject.sdk.spec.AgentCard;
-import org.a2aproject.sdk.spec.TaskNotFoundError;
 import org.a2aproject.sdk.spec.StreamingEventKind;
+import org.a2aproject.sdk.spec.TaskNotFoundError;
 import org.a2aproject.sdk.transport.rest.handler.RestHandler;
 import org.junit.jupiter.api.Test;
 import org.springframework.boot.autoconfigure.AutoConfigurations;
 import org.springframework.boot.test.context.runner.WebApplicationContextRunner;
-import org.springframework.http.ResponseEntity;
 import org.springframework.test.web.servlet.MockMvc;
 import org.springframework.test.web.servlet.MvcResult;
 import org.springframework.test.web.servlet.setup.MockMvcBuilders;
@@ -169,63 +168,72 @@ public void cancel() {
     assertEquals(0, controller.activeStreamCount());
   }
 
-
   @org.junit.jupiter.params.ParameterizedTest
   @org.junit.jupiter.params.provider.ValueSource(
       strings = {"before-subscribe", "after-subscribe", "during-request"})
-  void synchronousPublisherFailureReleasesResourcesBeforeMvcDispatch(String phase) throws Exception {
+  void synchronousPublisherFailureReleasesResourcesBeforeMvcDispatch(String phase)
+      throws Exception {
     for (String endpoint : new String[] {"/message:stream", "/tasks/task-1:subscribe"}) {
       RestHandler restHandler = mock(RestHandler.class);
       when(restHandler.createErrorResponse(any()))
-          .thenReturn(new RestHandler.HTTPRestResponse(
-              500, "application/a2a+json",
-              "{\"error\":{\"code\":500,\"status\":\"INTERNAL\",\"message\":\"Setup failed\"}}"));
+          .thenReturn(
+              new RestHandler.HTTPRestResponse(
+                  500,
+                  "application/a2a+json",
+                  "{\"error\":{\"code\":500,\"status\":\"INTERNAL\",\"message\":\"Setup failed\"}}"));
       RequestHandler requestHandler = mock(RequestHandler.class);
       AgentCard agentCard = mock(AgentCard.class);
-      when(agentCard.capabilities()).thenReturn(AgentCapabilities.builder().streaming(true).build());
+      when(agentCard.capabilities())
+          .thenReturn(AgentCapabilities.builder().streaming(true).build());
       var agentInterface = mock(org.a2aproject.sdk.spec.AgentInterface.class);
       when(agentInterface.protocolVersion()).thenReturn("1.0");
       when(agentCard.supportedInterfaces()).thenReturn(java.util.List.of(agentInterface));
       AtomicInteger subscriptionCancellations = new AtomicInteger();
       AtomicInteger eventConsumerCancellations = new AtomicInteger();
-      AtomicReference<Flow.Subscriber<? super StreamingEventKind>> subscriber = new AtomicReference<>();
+      AtomicReference<Flow.Subscriber<? super StreamingEventKind>> subscriber =
+          new AtomicReference<>();
       org.mockito.stubbing.Answer<Flow.Publisher<StreamingEventKind>> answer =
           invocation -> {
             ServerCallContext context = invocation.getArgument(1);
             context.setEventConsumerCancelCallback(eventConsumerCancellations::incrementAndGet);
             return receiver -> {
               subscriber.set(receiver);
               if (!phase.equals("before-subscribe")) {
-                receiver.onSubscribe(new Flow.Subscription() {
-                  @Override
-                  public void request(long count) {
-                    if (phase.equals("during-request")) {
-                      throw new IllegalStateException("Request failed");
-                    }
-                  }
-
-                  @Override
-                  public void cancel() {
-                    subscriptionCancellations.incrementAndGet();
-                  }
-                });
+                receiver.onSubscribe(
+                    new Flow.Subscription() {
+                      @Override
+                      public void request(long count) {
+                        if (phase.equals("during-request")) {
+                          throw new IllegalStateException("Request failed");
+                        }
+                      }
+
+                      @Override
+                      public void cancel() {
+                        subscriptionCancellations.incrementAndGet();
+                      }
+                    });
               }
               throw new IllegalStateException("Subscribe failed");
             };
           };
       when(requestHandler.onSubscribeToTask(any(), any())).thenAnswer(answer);
       when(requestHandler.onMessageSendStream(any(), any())).thenAnswer(answer);
       var controller = new A2AController(restHandler, requestHandler, agentCard);
-      MockMvc mockMvc = MockMvcBuilders.standaloneSetup(controller)
-          .addPlaceholderValue("a2at.server.path-prefix", "/a2a/json")
-          .build();
-
-      mockMvc.perform(post("/a2a/json" + endpoint)
-              .header("A2A-Version", "1.0")
-              .contentType("application/json")
-              .accept("text/event-stream")
-              .content("{\"message\":{\"messageId\":\"m1\",\"role\":\"ROLE_USER\","
-                  + "\"parts\":[{\"text\":\"test\"}]}}"))
+      MockMvc mockMvc =
+          MockMvcBuilders.standaloneSetup(controller)
+              .addPlaceholderValue("a2at.server.path-prefix", "/a2a/json")
+              .build();
+
+      mockMvc
+          .perform(
+              post("/a2a/json" + endpoint)
+                  .header("A2A-Version", "1.0")
+                  .contentType("application/json")
+                  .accept("text/event-stream")
+                  .content(
+                      "{\"message\":{\"messageId\":\"m1\",\"role\":\"ROLE_USER\","
+                          + "\"parts\":[{\"text\":\"test\"}]}}"))
           .andExpect(status().isInternalServerError())
           .andExpect(request().asyncNotStarted())
           .andExpect(content().contentTypeCompatibleWith("application/a2a+json"))
@@ -414,8 +422,7 @@ void slashActionAliasesAreOptIn() {
             .withBean(A2AController.class, () -> canonical)
             .withPropertyValues("a2at.server.enabled=true");
 
-    runner.run(
-        context -> assertFalse(context.containsBean("a2aSlashActionAliasController")));
+    runner.run(context -> assertFalse(context.containsBean("a2aSlashActionAliasController")));
     runner
         .withPropertyValues("a2at.server.slash-action-aliases-enabled=true")
         .run(context -> assertTrue(context.containsBean("a2aSlashActionAliasController")));