How to use

attr

method

in

io.netty.channel.Channel

@Override
public <T> Attribute<T> attr(AttributeKey<T> key) {
  return ctx.channel().attr(key);
}

  protected void copyAttrFromParentChannel(Channel parent, Channel child, AttributeKey key)
  {
    child.attr(key).set(parent.attr(key).get());
  }
}

public CommandData getCurrentCommand() {
  QueueCommand command = channel.attr(CommandsQueue.CURRENT_COMMAND).get();
  if (command instanceof CommandData) {
    return (CommandData)command;
  }
  return null;
}

private void incrementCurrentRequestsInFlight(ChannelHandlerContext ctx)
{
  currentRequestsGauge.set(currentRequests.incrementAndGet());
  ctx.channel().attr(ATTR_REQ_INFLIGHT).set(INFLIGHT);
}

  @Override
  public Unmarshaller getUnmarshaller(ChannelHandlerContext ctx) throws Exception {
    Attribute<Unmarshaller> attr = ctx.channel().attr(UNMARSHALLER);
    Unmarshaller unmarshaller = attr.get();
    if (unmarshaller == null) {
      unmarshaller = super.getUnmarshaller(ctx);
      attr.set(unmarshaller);
    }
    return unmarshaller;
  }
}

protected static boolean isHandlerActive(ChannelHandlerContext ctx) {
  Boolean suspended = ctx.channel().attr(READ_SUSPENDED).get();
  return suspended == null || Boolean.FALSE.equals(suspended);
}

  public static void setForChannel(Channel ch, ConnectionCloseType type)
  {
    ch.attr(ATTR_CLOSE_TYPE).set(type);
  }
}

  private void decrementCurrentRequestsIfOneInflight(ChannelHandlerContext ctx)
  {
    if (ctx.channel().attr(ATTR_REQ_INFLIGHT).getAndRemove() != null) {
      currentRequestsGauge.set(currentRequests.decrementAndGet());
    }
  }
}

@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
  LOG.warn("Exception caught", cause);
  NettyServerCnxn cnxn = ctx.channel().attr(CONNECTION_ATTRIBUTE).getAndSet(null);
  if (cnxn != null) {
    if (LOG.isDebugEnabled()) {
      LOG.debug("Closing {}", cnxn);
    }
    cnxn.close();
  }
}

@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception
{
  // Store a ref to the count of current inflight requests onto this channel. So that
  // other code can query it using getInflightRequestCountFromChannel().
  ctx.channel().attr(ATTR_CURRENT_REQS).set(currentRequests);
  super.channelActive(ctx);
}

  @Override
  public Unmarshaller getUnmarshaller(ChannelHandlerContext ctx) throws Exception {
    Attribute<Unmarshaller> attr = ctx.channel().attr(UNMARSHALLER);
    Unmarshaller unmarshaller = attr.get();
    if (unmarshaller == null) {
      unmarshaller = super.getUnmarshaller(ctx);
      attr.set(unmarshaller);
    }
    return unmarshaller;
  }
}

public String indicatedServerName() {
 if (chctx.channel().hasAttr(SslHandshakeCompletionHandler.SERVER_NAME_ATTR)) {
  return chctx.channel().attr(SslHandshakeCompletionHandler.SERVER_NAME_ATTR).get();
 } else {
  return null;
 }
}

public CommandData getCurrentCommand() {
  QueueCommand command = channel.attr(CommandsQueue.CURRENT_COMMAND).get();
  if (command instanceof CommandData) {
    return (CommandData)command;
  }
  return null;
}

@Override
public void uninstall( Channel channel )
{
  channel.attr( LOCK_KEY ).set( null );
}

  private void decrementCurrentRequestsIfOneInflight(ChannelHandlerContext ctx)
  {
    if (ctx.channel().attr(ATTR_REQ_INFLIGHT).getAndRemove() != null) {
      groupMetrics.getForCurrentEventLoop().decrementCurrentRequests();
    }
  }
}

 @Override
 public <T> Attribute<T> attr(AttributeKey<T> key) {
  return ctx.channel().attr(key);
 }
}

@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
  if (LOG.isTraceEnabled()) {
    LOG.trace("Channel inactive {}", ctx.channel());
  }
  allChannels.remove(ctx.channel());
  NettyServerCnxn cnxn = ctx.channel().attr(CONNECTION_ATTRIBUTE).getAndSet(null);
  if (cnxn != null) {
    if (LOG.isTraceEnabled()) {
      LOG.trace("Channel inactive caused close {}", cnxn);
    }
    cnxn.close();
  }
}

  protected void copyAttrFromParentChannel(Channel parent, Channel child, AttributeKey key)
  {
    child.attr(key).set(parent.attr(key).get());
  }
}

  @Override
  public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception
  {
    try {
      super.userEventTriggered(ctx, evt);
    }
    finally {
      if (evt instanceof HttpLifecycleChannelHandler.CompleteEvent) {
        ctx.channel().attr(ATTR_STATE).set(null);
      }
    }
  }
}

protected static boolean fireCompleteEventIfNotAlready(ChannelHandlerContext ctx, CompleteReason reason)
{
  // Only allow this method to run once per request.
  Attribute<State> attr = ctx.channel().attr(ATTR_STATE);
  State state = attr.get();
  if (state == null || state != State.STARTED)
    return false;
  
  attr.set(State.COMPLETED);
  HttpRequest request = ctx.channel().attr(ATTR_HTTP_REQ).get();
  HttpResponse response = ctx.channel().attr(ATTR_HTTP_RESP).get();
  // Cleanup channel attributes.
  ctx.channel().attr(ATTR_HTTP_REQ).set(null);
  ctx.channel().attr(ATTR_HTTP_RESP).set(null);
  // Fire the event to whole pipeline.
  ctx.pipeline().fireUserEventTriggered(new CompleteEvent(reason, request, response));
  
  return true;
}