Add Reactor Netty version of the Quote of the Moment example (#2636)

Provide a corresponding Reactor Netty version of the Quote of the
Moment example in the Netty project.

Related to #761

Co-authored-by: Violeta Georgieva <[email protected]>

reactor-netty-examples/src/main/java/reactor/netty/examples/udp/qotm/QuoteOfTheMomentClient.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2023 VMware, Inc. or its affiliates, All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package reactor.netty.examples.udp.qotm;
+
+import reactor.core.publisher.Mono;
+import reactor.netty.Connection;
+import reactor.netty.udp.UdpClient;
+
+public class QuoteOfTheMomentClient {
+
+	private static final int PORT = Integer.parseInt(System.getProperty("port", "7686"));
+
+	private static final boolean WIRETAP = System.getProperty("wiretap") != null;
+
+	public static void main(String[] args) {
+		UdpClient client = UdpClient.create()
+				.port(PORT)
+				.wiretap(WIRETAP);
+
+		Connection conn = client.connectNow();
+
+		conn.inbound()
+				.receive()
+				.asString()
+				.doOnNext(text -> {
+					if (text.startsWith("QOTM:")) {
+						System.out.println("Quote of the Moment: " + text.substring(6));
+						conn.disposeNow();
+					}
+				}).doOnError(err -> {
+					err.printStackTrace();
+					conn.disposeNow();
+				})
+				.subscribe();
+
+		conn.outbound()
+				.sendString(Mono.just("QOTM?"))
+				.then()
+				.subscribe();
+
+		conn.onReadIdle(5000, () -> {
+			System.err.println("QOTM request timed out.");
+			conn.disposeNow();
+		});
+
+		conn.onDispose().block();
+	}
+}

reactor-netty-examples/src/main/java/reactor/netty/examples/udp/qotm/QuoteOfTheMomentServer.java

@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2023 VMware, Inc. or its affiliates, All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package reactor.netty.examples.udp.qotm;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.channel.ChannelOption;
+import io.netty.channel.socket.DatagramPacket;
+import reactor.core.publisher.Flux;
+import reactor.netty.Connection;
+import reactor.netty.udp.UdpServer;
+
+import java.nio.charset.StandardCharsets;
+import java.util.Random;
+
+public class QuoteOfTheMomentServer {
+
+	private static final int PORT = Integer.parseInt(System.getProperty("port", "7686"));
+
+	private static final boolean WIRETAP = System.getProperty("wiretap") != null;
+
+	private static final Random random = new Random();
+
+	private static final String[] quotes = {"Where there is love there is life.",
+			"First they ignore you, then they laugh at you, then they fight you, then you win.",
+			"Be the change you want to see in the world.",
+			"The weak can never forgive. Forgiveness is the attribute of the strong."};
+
+	private static String nextQuote() {
+		int quoteId;
+		synchronized (random) {
+			quoteId = random.nextInt(quotes.length);
+		}
+		return quotes[quoteId];
+
+	}
+
+	public static void main(String[] args) {
+
+		UdpServer server = UdpServer
+				.create()
+				.port(PORT)
+				.wiretap(WIRETAP)
+				.option(ChannelOption.SO_BROADCAST, true)
+				.handle((in, out) -> {
+					Flux<DatagramPacket> inFlux = in
+							.receiveObject()
+							.handle((incoming, sink) -> {
+								if (incoming instanceof DatagramPacket) {
+									DatagramPacket packet = (DatagramPacket) incoming;
+									String content = packet.content()
+											.toString(StandardCharsets.UTF_8);
+
+									if ("QOTM?".equalsIgnoreCase(content)) {
+										String nextQuote = nextQuote();
+										ByteBuf byteBuf =
+												Unpooled.copiedBuffer("QOTM: " + nextQuote, StandardCharsets.UTF_8);
+										DatagramPacket response = new DatagramPacket(byteBuf, packet.sender());
+										sink.next(response);
+									}
+								}
+							});
+					return out.sendObject(inFlux);
+				});
+
+		Connection conn = server.bindNow();
+		conn.onDispose().block();
+	}
+
+}