private void runListener()

in commons-jcs3-core/src/main/java/org/apache/commons/jcs3/auxiliary/lateral/socket/tcp/LateralTCPListener.java [519:603]
71 lines of code
12 McCabe index (conditional complexity)

    private void runListener(final ServerSocketChannel serverSocket)
    {
        try (Selector selector = Selector.open())
        {
            serverSocket.register(selector, SelectionKey.OP_ACCEPT);
            log.debug("Waiting for clients to connect");

            // Check to see if we've been asked to exit, and exit
            while (!terminated.get())
            {
                final int activeKeys = selector.select(acceptTimeOut);
                if (activeKeys == 0)
                {
                    continue;
                }

                for (final Iterator<SelectionKey> i = selector.selectedKeys().iterator(); i.hasNext();)
                {
                    if (terminated.get())
                    {
                        break;
                    }

                    final SelectionKey key = i.next();

                    if (!key.isValid())
                    {
                        continue;
                    }

                    if (key.isAcceptable())
                    {
                        final ServerSocketChannel server = (ServerSocketChannel) key.channel();
                        final SocketChannel client = server.accept();
                        if (client == null)
                        {
                            //may happen in non-blocking mode
                            continue;
                        }

                        log.info("Connected to client at {0}", client.getRemoteAddress());

                        client.configureBlocking(false);
                        client.register(selector, SelectionKey.OP_READ);
                    }

                    if (key.isReadable())
                    {
                        handleClient(key);
                    }

                    i.remove();
                }
            }

            log.debug("Thread terminated, exiting gracefully");

            //close all registered channels
            selector.keys().forEach(key -> {
                try
                {
                    key.channel().close();
                }
                catch (final IOException e)
                {
                    log.warn("Problem closing channel", e);
                }
            });
        }
        catch (final IOException e)
        {
            log.error( "Exception caught in TCP listener", e );
        }
        finally
        {
            try
            {
                serverSocket.close();
            }
            catch (final IOException e)
            {
                log.error( "Exception closing TCP listener", e );
            }
        }
    }