Description of how Mqtt-publishing works

Mqtt-publish.java

/*

  Client-server interaction on different QOS levels


   QOS =0

   if server would like to publish something to the client
   _______________________________________________________________

   server
          ---PUBLISH---->
                           client
   _______________________________________________________________

  if client would like to publish something to the client
  _______________________________________________________________

   client
          ---PUBLISH---->
                          server
   _______________________________________________________________

   ###############################################################
   ###############################################################
   ###############################################################

   QOS =1

   if server would like to publish something to the client
   _______________________________________________________________

   server
          ---PUBLISH---->
                           client
          <---PUBACK----
   server
   ________________________________________________________________

  if client would like to publish something to the client

   client
          ---PUBLISH---->
                          server
          <---PUBACK----
   client
   _______________________________________________________________


   ###############################################################
   ###############################################################
   ###############################################################

   QOS=2

   if server would like to publish something to the client
   _______________________________________________________________

   server
          ---PUBLISH---->
                           client
          <---PUBREC----
   server
           ---PUBREL---->
                           client
          <---PUBCOMP---
   server
  _______________________________________________________________

  if client would like to publish something to the client
  _______________________________________________________________

   client
          ---PUBLISH---->
                          server
          <---PUBREC----
   client
           ---PUBREL---->
                          server
          <---PUBCOMP---
   client
   _______________________________________________________________

   */