聊聊artemis的ServerConnectionLifeCycleListener

序

本文主要研究一下artemis的ServerConnectionLifeCycleListener

BaseConnectionLifeCycleListener

activemq-artemis-2.11.0/artemis-core-client/src/main/java/org/apache/activemq/artemis/spi/core/remoting/BaseConnectionLifeCycleListener.java

public interface BaseConnectionLifeCycleListener<ProtocolClass> {

   void connectionCreated(ActiveMQComponent component, Connection connection, ProtocolClass protocol);

   void connectionDestroyed(Object connectionID);

   void connectionException(Object connectionID, ActiveMQException me);

   void connectionReadyForWrites(Object connectionID, boolean ready);
}

• BaseConnectionLifeCycleListener接口定义了connectionCreated、connectionDestroyed、connectionException、connectionReadyForWrites方法

ServerConnectionLifeCycleListener

activemq-artemis-2.11.0/artemis-server/src/main/java/org/apache/activemq/artemis/spi/core/remoting/ServerConnectionLifeCycleListener.java

public interface ServerConnectionLifeCycleListener extends BaseConnectionLifeCycleListener<ProtocolManager> {

}

• ServerConnectionLifeCycleListener继承了BaseConnectionLifeCycleListener，其泛型为ProtocolManager

RemotingServiceImpl

activemq-artemis-2.11.0/artemis-server/src/main/java/org/apache/activemq/artemis/core/remoting/server/impl/RemotingServiceImpl.java

public class RemotingServiceImpl implements RemotingService, ServerConnectionLifeCycleListener {

	//......

   @Override
   public void connectionCreated(final ActiveMQComponent component,
                                 final Connection connection,
                                 final ProtocolManager protocol) {
      if (server == null) {
         throw new IllegalStateException("Unable to create connection, server hasn't finished starting up");
      }

      ConnectionEntry entry = protocol.createConnectionEntry((Acceptor) component, connection);
      try {
         if (server.hasBrokerConnectionPlugins()) {
            server.callBrokerConnectionPlugins(plugin -> plugin.afterCreateConnection(entry.connection));
         }
      } catch (ActiveMQException t) {
         logger.warn("Error executing afterCreateConnection plugin method: {}", t.getMessage(), t);
         throw new IllegalStateException(t.getMessage(), t.getCause());

      }
      if (logger.isTraceEnabled()) {
         logger.trace("Connection created " + connection);
      }

      connections.put(connection.getID(), entry);
      connectionCountLatch.countUp();
      totalConnectionCount.incrementAndGet();
   }

   @Override
   public void connectionDestroyed(final Object connectionID) {

      if (logger.isTraceEnabled()) {
         logger.trace("Connection removed " + connectionID + " from server " + this.server, new Exception("trace"));
      }

      issueFailure(connectionID, new ActiveMQRemoteDisconnectException());
   }

   private void issueFailure(Object connectionID, ActiveMQException e) {
      ConnectionEntry conn = connections.get(connectionID);

      if (conn != null && !conn.connection.isSupportReconnect()) {
         RemotingConnection removedConnection = removeConnection(connectionID);
         if (removedConnection != null) {
            try {
               if (server.hasBrokerConnectionPlugins()) {
                  server.callBrokerConnectionPlugins(plugin -> plugin.afterDestroyConnection(removedConnection));
               }
            } catch (ActiveMQException t) {
               logger.warn("Error executing afterDestroyConnection plugin method: {}", t.getMessage(), t);
               conn.connection.fail(t);
               return;
            }
         }
         conn.connection.fail(e);
      }
   }

   @Override
   public void connectionException(final Object connectionID, final ActiveMQException me) {
      issueFailure(connectionID, me);
   }

   @Override
   public void connectionReadyForWrites(final Object connectionID, final boolean ready) {
   }

	//......
}

• RemotingServiceImpl实现了ServerConnectionLifeCycleListener接口，其connectionCreated在server.hasBrokerConnectionPlugins()为true的情况下会执行server.callBrokerConnectionPlugins(plugin -> plugin.afterCreateConnection(entry.connection))；其connectionDestroyed方法主要执行issueFailure，在server.hasBrokerConnectionPlugins()为true的情况下会执行server.callBrokerConnectionPlugins(plugin -> plugin.afterDestroyConnection(removedConnection))

ActiveMQServerImpl

activemq-artemis-2.11.0/artemis-server/src/main/java/org/apache/activemq/artemis/core/server/impl/ActiveMQServerImpl.java

public class ActiveMQServerImpl implements ActiveMQServer {

   //......

   public void registerBrokerPlugin(final ActiveMQServerBasePlugin plugin) {
      configuration.registerBrokerPlugin(plugin);
      plugin.registered(this);
   }

   public void unRegisterBrokerPlugin(final ActiveMQServerBasePlugin plugin) {
      configuration.unRegisterBrokerPlugin(plugin);
      plugin.unregistered(this);
   }

   public boolean hasBrokerConnectionPlugins() {
      return !getBrokerConnectionPlugins().isEmpty();
   }

   public List<ActiveMQServerConnectionPlugin> getBrokerConnectionPlugins() {
      return configuration.getBrokerConnectionPlugins();
   }

   public void callBrokerConnectionPlugins(final ActiveMQPluginRunnable<ActiveMQServerConnectionPlugin> pluginRun) throws ActiveMQException {
      callBrokerPlugins(getBrokerConnectionPlugins(), pluginRun);
   }

   private <P extends ActiveMQServerBasePlugin> void callBrokerPlugins(final List<P> plugins, final ActiveMQPluginRunnable<P> pluginRun) throws ActiveMQException {
      if (pluginRun != null) {
         for (P plugin : plugins) {
            try {
               pluginRun.run(plugin);
            } catch (Throwable e) {
               if (e instanceof ActiveMQException) {
                  logger.debug("plugin " + plugin + " is throwing ActiveMQException");
                  throw (ActiveMQException) e;
               } else {
                  logger.warn("Internal error on plugin " + pluginRun, e.getMessage(), e);
               }
            }
         }
      }
   }

   //......
}

• callBrokerPlugins方法会遍历plugins，然后挨个执行pluginRun.run(plugin)方法

小结

BaseConnectionLifeCycleListener接口定义了connectionCreated、connectionDestroyed、connectionException、connectionReadyForWrites方法；RemotingServiceImpl实现了ServerConnectionLifeCycleListener接口，其connectionCreated在server.hasBrokerConnectionPlugins()为true的情况下会执行server.callBrokerConnectionPlugins(plugin -> plugin.afterCreateConnection(entry.connection))；其connectionDestroyed方法主要执行issueFailure，在server.hasBrokerConnectionPlugins()为true的情况下会执行server.callBrokerConnectionPlugins(plugin -> plugin.afterDestroyConnection(removedConnection))

doc

• ServerConnectionLifeCycleListener

来源：oschina

链接：https://my.oschina.net/go4it/blog/3160494