| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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 |
| * |
| * http://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 org.apache.ignite.examples.messaging; |
| |
| import java.util.concurrent.CountDownLatch; |
| import org.apache.ignite.Ignite; |
| import org.apache.ignite.IgniteException; |
| import org.apache.ignite.Ignition; |
| import org.apache.ignite.cluster.ClusterGroup; |
| import org.apache.ignite.examples.ExampleNodeStartup; |
| import org.apache.ignite.examples.ExamplesUtils; |
| |
| /** |
| * Demonstrates simple message exchange between local and remote nodes. |
| * <p> |
| * To run this example you must have at least one remote node started. |
| * <p> |
| * Remote nodes should always be started with special configuration file which |
| * enables P2P class loading: {@code 'ignite.{sh|bat} examples/config/example-ignite.xml'}. |
| * <p> |
| * Alternatively you can run {@link ExampleNodeStartup} in another JVM which will start node |
| * with {@code examples/config/example-ignite.xml} configuration. |
| */ |
| public class MessagingPingPongExample { |
| /** |
| * Executes example. |
| * |
| * @param args Command line arguments, none required. |
| * @throws Exception If example execution failed. |
| */ |
| public static void main(String[] args) throws Exception { |
| // Game is played over the default ignite. |
| try (Ignite ignite = Ignition.start("examples/config/example-ignite.xml")) { |
| if (!ExamplesUtils.checkMinTopologySize(ignite.cluster(), 2)) |
| return; |
| |
| System.out.println(); |
| System.out.println(">>> Messaging ping-pong example started."); |
| |
| // Pick random remote node as a partner. |
| ClusterGroup nodeB = ignite.cluster().forRemotes().forRandom(); |
| |
| // Note that both nodeA and nodeB will always point to |
| // same nodes regardless of whether they were implicitly |
| // serialized and deserialized on another node as part of |
| // anonymous closure's state during its remote execution. |
| |
| // Set up remote player. |
| ignite.message(nodeB).remoteListen(null, (nodeId, rcvMsg) -> { |
| System.out.println("Received message [msg=" + rcvMsg + ", sender=" + nodeId + ']'); |
| |
| if ("PING".equals(rcvMsg)) { |
| ignite.message(ignite.cluster().forNodeId(nodeId)).send(null, "PONG"); |
| |
| return true; // Continue listening. |
| } |
| |
| return false; // Unsubscribe. |
| }); |
| |
| int MAX_PLAYS = 10; |
| |
| final CountDownLatch cnt = new CountDownLatch(MAX_PLAYS); |
| |
| // Set up local player. |
| ignite.message().localListen(null, (nodeId, rcvMsg) -> { |
| System.out.println("Received message [msg=" + rcvMsg + ", sender=" + nodeId + ']'); |
| |
| if (cnt.getCount() == 1) { |
| ignite.message(ignite.cluster().forNodeId(nodeId)).send(null, "STOP"); |
| |
| cnt.countDown(); |
| |
| return false; // Stop listening. |
| } |
| else if ("PONG".equals(rcvMsg)) |
| ignite.message(ignite.cluster().forNodeId(nodeId)).send(null, "PING"); |
| else |
| throw new IgniteException("Received unexpected message: " + rcvMsg); |
| |
| cnt.countDown(); |
| |
| return true; // Continue listening. |
| }); |
| |
| // Serve! |
| ignite.message(nodeB).send(null, "PING"); |
| |
| // Wait til the game is over. |
| try { |
| cnt.await(); |
| } |
| catch (InterruptedException e) { |
| System.err.println("Hm... let us finish the game!\n" + e); |
| } |
| } |
| } |
| } |