// Create an A2AClient (the URL specified is the server agent's URL)
A2AClient client = new A2AClient("http://localhost:1234");

// Send a text message to the server agent
Message message = A2A.toUserMessage("tell me a joke"); // the message ID will be automatically generated for you
MessageSendParams params = new MessageSendParams.Builder()
        .id("task-1234") // id is optional
        .message(message)
        .build();
SendMessageResponse response = client.sendMessage(params);        

Message message = A2A.toUserMessage("tell me a joke", "message-1234"); // messageId is message-1234

// Retrieve the task with id "task-1234"
GetTaskResponse response = client.getTask("task-1234");

// You can also specify the maximum number of items of history for the task
// to include in the response
GetTaskResponse response = client.getTask(new TaskQueryParams("task-1234", 10));

// Cancel the task we previously submitted with id "task-1234"
CancelTaskResponse response = client.cancelTask("task-1234");

// You can also specify additional properties using a map
Map<String, Object> metadata = ...        
CancelTaskResponse response = client.cancelTask(new TaskIdParams("task-1234", metadata));

// Get task push notification
GetTaskPushNotificationResponse response = client.getTaskPushNotificationConfig("task-1234");

// You can also specify additional properties using a map
Map<String, Object> metadata = ...
GetTaskPushNotificationResponse response = client.getTaskPushNotificationConfig(new TaskIdParams("task-1234", metadata));

// Set task push notification configuration
PushNotificationConfig pushNotificationConfig = new PushNotificationConfig.Builder()
        .url("https://example.com/callback")
        .authenticationInfo(new AuthenticationInfo(Collections.singletonList("jwt"), null))
        .build());
SetTaskPushNotificationResponse response = client.setTaskPushNotificationConfig("task-1234", pushNotificationConfig);

// Send a text message to the remote agent
Message message = A2A.toUserMessage("tell me some jokes"); // the message ID will be automatically generated for you
MessageSendParams params = new MessageSendParams.Builder()
        .id("task-1234") // id is optional
        .message(message)
        .build();

// Create a handler that will be invoked for Task, Message, TaskStatusUpdateEvent, and TaskArtifactUpdateEvent
Consumer<StreamingEventType> eventHandler = event -> {...};

// Create a handler that will be invoked if an error is received
Consumer<JSONRPCError> errorHandler = error -> {...};

// Create a handler that will be invoked in the event of a failure
Runnable failureHandler = () -> {...};

// Send the streaming message to the remote agent
client.sendStreamingMessage(params, eventHandler, errorHandler, failureHandler);

AgentCard serverAgentCard = client.getAgentCard();

// http://localhost:1234 is the base URL for the agent whose card we want to retrieve
AgentCard agentCard = A2A.getAgentCard("http://localhost:1234");