Make SDK and TCK agent executors use TaskUpdater

Author: kabir

src/test/java/io/a2a/server/apps/AgentExecutorProducer.java

@@ -6,6 +6,7 @@
 import io.a2a.server.agentexecution.AgentExecutor;
 import io.a2a.server.agentexecution.RequestContext;
 import io.a2a.server.events.EventQueue;
+import io.a2a.server.tasks.TaskUpdater;
 import io.a2a.spec.JSONRPCError;
 import io.a2a.spec.Task;
 import io.a2a.spec.TaskState;
@@ -29,12 +30,8 @@ public void execute(RequestContext context, EventQueue eventQueue) throws JSONRP
             @Override
             public void cancel(RequestContext context, EventQueue eventQueue) throws JSONRPCError {
                 if (context.getTask().getId().equals("cancel-task-123")) {
-                    Task task = context.getTask();
-                    Task updated = new Task.Builder(task)
-                            .status(new TaskStatus(TaskState.CANCELED))
-                            .build();
-
-                    eventQueue.enqueueEvent(updated);
+                    TaskUpdater taskUpdater = new TaskUpdater(eventQueue, context);
+                    taskUpdater.cancel();
                 } else if (context.getTask().getId().equals("cancel-task-not-supported-123")) {
                     throw new UnsupportedOperationError();
                 }

src/test/java/io/a2a/server/requesthandlers/JSONRPCHandlerTest.java

@@ -35,6 +35,7 @@
 import io.a2a.server.tasks.PushNotifier;
 import io.a2a.server.tasks.ResultAggregator;
 import io.a2a.server.tasks.TaskStore;
+import io.a2a.server.tasks.TaskUpdater;
 import io.a2a.spec.AgentCapabilities;
 import io.a2a.spec.AgentCard;
 import io.a2a.spec.Artifact;
@@ -166,11 +167,8 @@ public void testOnCancelTaskSuccess() throws Exception {
             // Looking at the Python implementation, they typically use AgentExecutors that
             // don't support cancellation. So my theory is the Agent updates the task to the CANCEL status
             Task task = context.getTask();
-            Task updated = new Task.Builder(task)
-                    .status(new TaskStatus(TaskState.CANCELED))
-                    .build();
-
-            eventQueue.enqueueEvent(updated);
+            TaskUpdater taskUpdater = new TaskUpdater(eventQueue, context);
+            taskUpdater.cancel();
         };
 
         CancelTaskRequest request = new CancelTaskRequest("111", new TaskIdParams(MINIMAL_TASK.getId()));