Package io.micronaut.http.netty.reactive

Class HandlerPublisher<T>

  • Type Parameters:
    T - The publisher type
    All Implemented Interfaces:
    HotObservable<T>, io.netty.channel.ChannelHandler, io.netty.channel.ChannelInboundHandler, io.netty.channel.ChannelOutboundHandler, org.reactivestreams.Publisher<T>
    @Internal
public class HandlerPublisher<T>
extends io.netty.channel.ChannelDuplexHandler
implements HotObservable<T>
    Publisher for a Netty Handler.

    This publisher supports only one subscriber.

    All interactions with the subscriber are done from the handlers executor, hence, they provide the same happens before semantics that Netty provides.

    The handler publishes all messages that match the type as specified by the passed in class. Any non matching messages are forwarded to the next handler.

    The publisher will signal complete if it receives a channel inactive event.

    The publisher will release any messages that it drops (for example, messages that are buffered when the subscriber cancels), but other than that, it does not release any messages. It is up to the subscriber to release messages.

    If the subscriber cancels, the publisher will send a close event up the channel pipeline.

    All errors will short circuit the buffer, and cause publisher to immediately call the subscribers onError method, dropping the buffer.

    The publisher can be subscribed to or placed in a handler chain in any order.

    Since:
    1.0

    • Nested Class Summary

      • Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler

        io.netty.channel.ChannelHandler.Sharable

    • Constructor Summary

      Constructors 
      Constructor Description
      HandlerPublisher​(io.netty.util.concurrent.EventExecutor executor, java.lang.Class<? extends T> subscriberMessageType)
      Create a handler publisher.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      protected boolean acceptInboundMessage​(java.lang.Object msg)
      Returns true if the given message should be handled.
      protected void cancelled()
      Override to handle when a subscriber cancels the subscription.
      void channelActive​(io.netty.channel.ChannelHandlerContext ctx)  
      void channelInactive​(io.netty.channel.ChannelHandlerContext ctx)  
      void channelRead​(io.netty.channel.ChannelHandlerContext ctx, java.lang.Object message)  
      void channelRegistered​(io.netty.channel.ChannelHandlerContext ctx)  
      void closeIfNoSubscriber()
      Releases buffered data if there is no subscriber.
      void exceptionCaught​(io.netty.channel.ChannelHandlerContext ctx, java.lang.Throwable cause)  
      void handlerAdded​(io.netty.channel.ChannelHandlerContext ctx)  
      void handlerRemoved​(io.netty.channel.ChannelHandlerContext ctx)  
      protected void requestDemand()
      Override to intercept when demand is requested.
      void subscribe​(org.reactivestreams.Subscriber<? super T> subscriber)  

      • Methods inherited from class io.netty.channel.ChannelDuplexHandler

        bind, close, connect, deregister, disconnect, flush, read, write

      • Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter

        channelReadComplete, channelUnregistered, channelWritabilityChanged, userEventTriggered

      • Methods inherited from class io.netty.channel.ChannelHandlerAdapter

        ensureNotSharable, isSharable

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Constructor Detail

      • HandlerPublisher

        public HandlerPublisher​(io.netty.util.concurrent.EventExecutor executor,
                        java.lang.Class<? extends T> subscriberMessageType)
        Create a handler publisher.

        The supplied executor must be the same event loop as the event loop that this handler is eventually registered with, if not, an exception will be thrown when the handler is registered.

        Parameters:
        executor - The executor to execute asynchronous events from the subscriber on.
        subscriberMessageType - The type of message this publisher accepts.

    • Method Detail

      • subscribe

        public void subscribe​(org.reactivestreams.Subscriber<? super T> subscriber)
        Specified by:
        subscribe in interface org.reactivestreams.Publisher<T>

      • acceptInboundMessage

        protected boolean acceptInboundMessage​(java.lang.Object msg)
        Returns true if the given message should be handled. If false it will be passed to the next ChannelInboundHandler in the ChannelPipeline.
        Parameters:
        msg - The message to check.
        Returns:
        True if the message should be accepted.

      • cancelled

        protected void cancelled()
        Override to handle when a subscriber cancels the subscription.

        By default, this method will simply close the channel.

      • requestDemand

        protected void requestDemand()
        Override to intercept when demand is requested.

        By default, a channel read is invoked.

      • handlerAdded

        public void handlerAdded​(io.netty.channel.ChannelHandlerContext ctx)
        Specified by:
        handlerAdded in interface io.netty.channel.ChannelHandler
        Overrides:
        handlerAdded in class io.netty.channel.ChannelHandlerAdapter

      • channelRegistered

        public void channelRegistered​(io.netty.channel.ChannelHandlerContext ctx)
        Specified by:
        channelRegistered in interface io.netty.channel.ChannelInboundHandler
        Overrides:
        channelRegistered in class io.netty.channel.ChannelInboundHandlerAdapter

      • channelActive

        public void channelActive​(io.netty.channel.ChannelHandlerContext ctx)
        Specified by:
        channelActive in interface io.netty.channel.ChannelInboundHandler
        Overrides:
        channelActive in class io.netty.channel.ChannelInboundHandlerAdapter

      • channelRead

        public void channelRead​(io.netty.channel.ChannelHandlerContext ctx,
                        java.lang.Object message)
        Specified by:
        channelRead in interface io.netty.channel.ChannelInboundHandler
        Overrides:
        channelRead in class io.netty.channel.ChannelInboundHandlerAdapter

      • channelInactive

        public void channelInactive​(io.netty.channel.ChannelHandlerContext ctx)
        Specified by:
        channelInactive in interface io.netty.channel.ChannelInboundHandler
        Overrides:
        channelInactive in class io.netty.channel.ChannelInboundHandlerAdapter

      • handlerRemoved

        public void handlerRemoved​(io.netty.channel.ChannelHandlerContext ctx)
        Specified by:
        handlerRemoved in interface io.netty.channel.ChannelHandler
        Overrides:
        handlerRemoved in class io.netty.channel.ChannelHandlerAdapter

      • exceptionCaught

        public void exceptionCaught​(io.netty.channel.ChannelHandlerContext ctx,
                            java.lang.Throwable cause)
        Specified by:
        exceptionCaught in interface io.netty.channel.ChannelHandler
        Specified by:
        exceptionCaught in interface io.netty.channel.ChannelInboundHandler
        Overrides:
        exceptionCaught in class io.netty.channel.ChannelInboundHandlerAdapter