org.jgroups.demos.PubSub Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of wildfly-client-all

This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

There is a newer version: 32.0.0.Final

Show newest version

package org.jgroups.demos;

import org.jgroups.Global;
import org.jgroups.JChannel;
import org.jgroups.Message;
import org.jgroups.ReceiverAdapter;
import org.jgroups.conf.ConfiguratorFactory;
import org.jgroups.conf.ProtocolConfiguration;
import org.jgroups.conf.ProtocolStackConfigurator;
import org.jgroups.util.Util;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Simple pub-sub program using a shared transport: every topic creates a new channel
 * @author bela
 * @since 3.0
 */
public class PubSub {
    final Map topics=new HashMap<>();


    void start(String props) throws Exception {
        System.out.println("\n========== PubSub instance started =========");
        System.out.println("Valid commands are:");
        System.out.println("subscribe ");
        System.out.println("unsubscribe ");
        System.out.println("exit");
        System.out.println("print (prints all topics)");
        System.out.println(": \n\n");

        System.out.println("Example");
        System.out.println("subscribe one\nsubscribe two\none: hello world\n\n");
        for(;;) {
            System.out.print("> ");
            String line=Util.readLine(System.in).trim();
            if(line.startsWith("subscribe")) {
                final String topic=line.substring("subscribe".length()).trim();
                if(!topics.containsKey(topic)) {
                    // we need to make sure "singleton_name" is set in the transport
                    JChannel ch=createSharedChannel("pubsub", props);
                    ch.setReceiver(new ReceiverAdapter() {
                        public void receive(Message msg) {
                            System.out.println("[" + topic + "] << " + msg.getObject());
                        }
                    });
                    ch.connect(topic);
                    topics.put(topic, ch);
                    System.out.println("subscribed to topic \"" + topic + "\"; current subscriptions: " + topics.keySet());
                }
                continue;
            }
            if(line.startsWith("unsubscribe")) {
                final String topic=line.substring("unsubscribe".length()).trim();
                JChannel ch=topics.remove(topic);
                if(ch == null) {
                    System.err.println("Topic \"" + topic + "\" not found");
                    continue;
                }
                Util.close(ch);
                System.out.println("unsubscribed from topic \"" + topic + "\"; current subscriptions: " + topics.keySet());
                continue;
            }
            if(line.startsWith("exit"))
                break;
            if(line.startsWith("print")) {
                System.out.println("topics: " + topics.keySet());
                continue;
            }
            int index=line.indexOf(":");
            if(index == -1) {
                // post to all topics
                for(JChannel ch: topics.values()) {
                    Message msg=new Message(null, null, line);
                    ch.send(msg);
                }
                continue;
            }
            String topic=line.substring(0, index).trim();
            String message=line.substring(index).trim();
            JChannel ch=topics.get(topic);
            if(ch == null) {
                System.err.println("sending to topic \"" + topic + "\" failed as topic doesn't exist, subscribe first");
                continue;
            }
            Message msg=new Message(null, null, message);
            ch.send(msg);
        }
        for(JChannel ch: topics.values())
            Util.close(ch);
    }

    private static JChannel createSharedChannel(String singleton_name, String props) throws Exception {
        ProtocolStackConfigurator config=ConfiguratorFactory.getStackConfigurator(props);
        List protocols=config.getProtocolStack();
        ProtocolConfiguration transport=protocols.get(0);
        transport.getProperties().put(Global.SINGLETON_NAME, singleton_name);
        return new JChannel(config);
    }

    
    public static void main(final String[] args) throws Exception {
        String props=null;
        for(int i=0; i < args.length; i++) {
            if(args[i].equals("-props")) {
                props=args[++i];
                continue;
            }
            help();
            return;
        }

        new PubSub().start(props);
    }


    protected static void help() {
        System.out.println("PubSub [-props props]");
        System.out.println("Valid commands are:");
        System.out.println("subscribe ");
        System.out.println("unsubscribe ");
        System.out.println("exit");
        System.out.println("print (prints all topics)");
        System.out.println(": \n\n");

        System.out.println("Example");
        System.out.println("subscribe one\nsubscribe two\none: hello world");
    }




}