Red Hat 的 Quarkus 和 WildFly 团队与 Google 合作发布 Agent2Agent Java SDK

import io.a2a.spec.AgentCapabilities;
import io.a2a.spec.AgentCard;
import io.a2a.spec.AgentSkill;
import io.a2a.spec.PublicAgentCard;
...

@ApplicationScoped
public class WeatherAgentCardProducer {

    @Produces
    @PublicAgentCard
    public AgentCard agentCard() {
        return new AgentCard.Builder()
                .name("Weather Agent")
                .description("Helps with weather")
                .url("https://:10001")
                .version("1.0.0")
                .capabilities(new AgentCapabilities.Builder()
                        .streaming(true)
                        .pushNotifications(false)
                        .stateTransitionHistory(false)
                        .build())
                .defaultInputModes(Collections.singletonList("text"))
                .defaultOutputModes(Collections.singletonList("text"))
                .skills(Collections.singletonList(new AgentSkill.Builder()
                        .id("weather_search")
                        .name("Search weather")
                        .description("Helps with weather in city, or states")
                        .tags(Collections.singletonList("weather"))
                        .examples(List.of("weather in LA, CA"))
                        .build()))
                .build();
    }
}

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.Message;
import io.a2a.spec.Part;
import io.a2a.spec.Task;
import io.a2a.spec.TaskNotCancelableError;
import io.a2a.spec.TaskState;
import io.a2a.spec.TextPart;
...

@ApplicationScoped
public class WeatherAgentExecutorProducer {

    @Inject
    WeatherAgent weatherAgent;

    @Produces
    public AgentExecutor agentExecutor() {
        return new WeatherAgentExecutor(weatherAgent);
    }

    private static class WeatherAgentExecutor implements AgentExecutor {

        private final WeatherAgent weatherAgent;

        public WeatherAgentExecutor(WeatherAgent weatherAgent) {
            this.weatherAgent = weatherAgent;
        }

        @Override
        public void execute(RequestContext context, EventQueue eventQueue) throws JSONRPCError {
            TaskUpdater updater = new TaskUpdater(context, eventQueue);

            // mark the task as submitted and start working on it
            if (context.getTask() == null) {
                updater.submit();
            }
            updater.startWork();

            // extract the text from the message
            String userMessage = extractTextFromMessage(context.getMessage());

            // call the weather agent with the user's message
            String response = weatherAgent.chat(userMessage);

            // create the response part
            TextPart responsePart = new TextPart(response, null);
            List<Part<?>> parts = List.of(responsePart);

            // add the response as an artifact and complete the task
            updater.addArtifact(parts, null, null, null);
            updater.complete();
        }

        @Override
        public void cancel(RequestContext context, EventQueue eventQueue) throws JSONRPCError {
            Task task = context.getTask();

            if (task.getStatus().state() == TaskState.CANCELED) {
                // task already cancelled
                throw new TaskNotCancelableError();
            }

            if (task.getStatus().state() == TaskState.COMPLETED) {
                // task already completed
                throw new TaskNotCancelableError();
            }

            // cancel the task
            TaskUpdater updater = new TaskUpdater(context, eventQueue);
            updater.cancel();
        }

        private String extractTextFromMessage(Message message) {
            StringBuilder textBuilder = new StringBuilder();
            if (message.getParts() != null) {
                for (Part part : message.getParts()) {
                    if (part instanceof TextPart textPart) {
                        textBuilder.append(textPart.getText());
                    }
                }
            }
            return textBuilder.toString();
        }
    }
}

// Create an A2AClient (the URL specified is the server agent's URL, be sure to replace it with the actual URL of the A2A server you want to connect to)
A2AClient client = new A2AClient("https://:1234");

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

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