|==> grpc-demo			   父级工程， 管理依赖相关
     |==>grpc-demo-sdk     通用jar依赖，生成protobuf对象与gRPC Service，供提供方与调用方使用
     |==>grpc-server-demo  服务端，提供下单及订单查询服务
     |==>grpc-client-demo  客户端，负责调用gRPC服务

/**
 * @author snowalker
 * @version 1.0
 * @date 2022/3/12 23:47
 * @className
 * @desc
 */
public class OrderServiceImpl extends OrderServiceGrpc.OrderServiceImplBase {
	private static final Logger logger = Logger.getLogger(OrderServiceImpl.class.getName());
	private static final Map<Integer, LinkedList<UserOrder>> USER_MEMORY_ORDER_BOOK = Maps.newConcurrentMap();
	/**
	 * <pre>
	 * 查询用户订单列表
	 * </pre>
	 *
	 * @param request
	 * @param responseObserver
	 */
	@Override
	public void queryUserOrders(QueryUserOrderRequest request, StreamObserver<QueryUserOrderResponse> responseObserver) {
		int userId = request.getUserId();
		// 查询订单
		List<UserOrder> orders = USER_MEMORY_ORDER_BOOK.getOrDefault(userId, Lists.newLinkedList());
		// 计算总价
		String totalPrice = calculateTotalPrice(orders);
		// 组装response
		QueryUserOrderResponse queryUserOrderResponse = QueryUserOrderResponse.newBuilder()
				.setUserId(userId)
				.addAllUserOrder(orders)
				.setTotalPrice(totalPrice)
				.build();
		logger.info("[Server] queryUserOrders, request:" + request.toString() + "\n" + "response:" + queryUserOrderResponse.toString());
		// 响应
		responseObserver.onNext(queryUserOrderResponse);
		responseObserver.onCompleted();
	}
	private String calculateTotalPrice(List<UserOrder> orders) {
		Optional<BigDecimal> count = orders.stream()
				.map(order -> new BigDecimal(order.getOrderAmount()).multiply(new BigDecimal(order.getOrderPrice())))
				.reduce(BigDecimal::add);
		return count.orElseGet(() -> BigDecimal.ZERO).toPlainString();
	}
	/**
	 * <pre>
	 * 下单
	 * </pre>
	 *
	 * @param request
	 * @param responseObserver
	 */
	@Override
	public void placeOrder(PlaceOrderRequest request, StreamObserver<PlaceOrderRequestResponse> responseObserver) {
		ThreadLocalRandom orderIdGenerator = ThreadLocalRandom.current();
		PlaceOrderRequestResponse.Builder placeOrderRequestResponse = PlaceOrderRequestResponse.newBuilder();
		int userId = request.getUserId();
		if (request.getPlaceUserOrderParamCount() <= 0) {
			placeOrderRequestResponse.setUserId(userId).setResultCode(ResultCode.FAILURE).build();
			responseObserver.onNext(placeOrderRequestResponse.build());
			responseObserver.onCompleted();
		}
		// 获取用户订单列表
		LinkedList<UserOrder> userOrderList = USER_MEMORY_ORDER_BOOK.getOrDefault(userId, Lists.newLinkedList());
		if (userOrderList.size() == 0) {
			USER_MEMORY_ORDER_BOOK.put(userId, Lists.newLinkedList());
		}
		int orderId = getOrderId(orderIdGenerator);
		// 本次订单
		List<UserOrder> userOrders = request.getPlaceUserOrderParamList().stream().map(
				param -> UserOrder.newBuilder()
						.setOrderId(orderId)
						.setOrderAmount(param.getOrderAmount())
						.setOrderPrice(param.getOrderPrice())
						.setProductId(param.getProductId())
						.build()).collect(Collectors.toList());
		// 追加订单列表
		userOrderList.addAll(userOrders);
		USER_MEMORY_ORDER_BOOK.put(userId, userOrderList);
		// 响应
		responseObserver.onNext(placeOrderRequestResponse.setUserId(userId).setResultCode(ResultCode.SUCCESS).build());
		responseObserver.onCompleted();
	}
	private int getOrderId(ThreadLocalRandom orderIdGenerator) {
		int orderId = orderIdGenerator.nextInt();
		if (orderId < 0) {
			orderId *= -1;
		}
		return orderId;
	}
}

/**
 * @author snowalker
 * @version 1.0
 * @date 2022/3/12 23:46
 * @desc 服务端启动类
 */
public class OrderServerBoot {
	private static final Logger logger = Logger.getLogger(OrderServerBoot.class.getName());
	private Server server;
	@SneakyThrows
	private void startServer() {
		int serverPort = 10880;
		server = ServerBuilder.forPort(serverPort)
				.addService(new OrderServiceImpl())
				.build();
		server.start();
		logger.info("OrderServerBoot started, listening on:" + serverPort);
		// 优雅停机
		addGracefulShowdownHook();
	}
	private void addGracefulShowdownHook() {
		Runtime.getRuntime().addShutdownHook(new Thread(() -> {
			// Use stderr here since the logger may have been reset by its JVM shutdown hook.
			System.err.println("*** shutting down gRPC server since JVM is shutting down");
			OrderServerBoot.this.stop();
			System.err.println("*** server shut down");
		}));
	}
	/**
	 * 服务关闭
	 */
	private void stop() {
		if (server != null) {
			server.shutdown();
		}
	}
	/**
	 * 由于 grpc 库使用守护线程，因此在主线程上等待终止。
	 */
	private void blockUntilShutdown() throws InterruptedException {
		if (server != null) {
			server.awaitTermination();
		}
	}
	@SneakyThrows
	public static void main(String[] args) {
		OrderServerBoot boot = new OrderServerBoot();
		// 启动服务
		boot.startServer();
		// 主线程等待终止
		boot.blockUntilShutdown();
	}
}

public class OrderClientAgent {
	private static final Logger logger = Logger.getLogger(OrderClientAgent.class.getName());
	private final ManagedChannel channel;
	// 客户端请求服务端的桩
	private final OrderServiceGrpc.OrderServiceBlockingStub orderServiceBlockingStub;
	public OrderClientAgent(String host, int port) {
		this(ManagedChannelBuilder.forAddress(host, port)
				//使用非安全机制传输,默认情况下，通道是安全的（通过SSLTLS）
				.usePlaintext()
				.build());
	}
	OrderClientAgent(ManagedChannel channel) {
		this.channel = channel;
		orderServiceBlockingStub = OrderServiceGrpc.newBlockingStub(channel);
	}
	public void shutdown() throws InterruptedException {
		channel.shutdown().awaitTermination(5, TimeUnit.SECONDS);
	}
	/**
	 * 下单
	 * @param request
	 */
	public PlaceOrderRequestResponse placeOrder(PlaceOrderRequest request) {
		logger.info("client placeOrder start. request:" + request.toString());
		PlaceOrderRequestResponse placeOrderRequestResponse;
		try {
			placeOrderRequestResponse = orderServiceBlockingStub.placeOrder(request);
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}
		return placeOrderRequestResponse;
	}
	/**
	 * 订单查询
	 * @param request
	 * @return
	 */
	public QueryUserOrderResponse queryOrders(QueryUserOrderRequest request) {
		logger.info("client queryOrders start. request:" + request.toString());
		QueryUserOrderResponse queryUserOrderResponse;
		try {
			queryUserOrderResponse = orderServiceBlockingStub.queryUserOrders(request);
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}
		return queryUserOrderResponse;
	}
}

/**
 * @author snowalker
 * @version 1.0
 * @date 2022/3/12 23:56
 * @desc 客户端启动类
 */
public class OrderClientBoot {
   private static final Logger logger = Logger.getLogger(OrderClientBoot.class.getName());
   @SneakyThrows
   public static void main(String[] args) {
      int port = 10880;
      OrderClientAgent orderClientAgent = new OrderClientAgent("127.0.0.1", port);
      try {
         int userId = 10086;
         // 下单
         doPlaceOrder(orderClientAgent, userId);
         // 查订单
         doQueryOrder(orderClientAgent, userId);
      } finally {
         orderClientAgent.shutdown();
      }
   }
   private static void doQueryOrder(OrderClientAgent orderClientAgent, int userId) {
      QueryUserOrderRequest queryUserOrderRequest = QueryUserOrderRequest.newBuilder()
            .setUserId(userId)
            .buildPartial();
      QueryUserOrderResponse queryUserOrderResponse = orderClientAgent.queryOrders(queryUserOrderRequest);
      logger.info("client queryOrders end. response:" + queryUserOrderResponse.toString());
   }
   private static void doPlaceOrder(OrderClientAgent orderClientAgent, int userId) {
      PlaceUserOrderParam orderParam0 = PlaceUserOrderParam.newBuilder()
            .setProductId(1)
            .setOrderAmount("15.00")
            .setOrderPrice("12.50")
            .build();
      PlaceUserOrderParam orderParam1 = PlaceUserOrderParam.newBuilder()
            .setProductId(2)
            .setOrderAmount("2.00")
            .setOrderPrice("10.00")
            .build();
      PlaceOrderRequest placeOrderRequest = PlaceOrderRequest.newBuilder()
            .setUserId(userId)
            .addAllPlaceUserOrderParam(Lists.newArrayList(orderParam0, orderParam1))
            .buildPartial();
      PlaceOrderRequestResponse placeOrderRequestResponse = orderClientAgent.placeOrder(placeOrderRequest);
      logger.info("client placeOrder end. response:" + placeOrderRequestResponse.toString() + ",resultCode:" + placeOrderRequestResponse.getResultCode());
   }
}