Channel

Channel是网络传输中的实体，它代表了一个开放的连接，可以进行数据的读写操作。

channel init

        final String A = "a";
        final String B = "B";
        // inbound handler
        ChannelHandler handler = new ChannelInboundHandlerAdapter() {
            @Override
            public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
                ctx.fireChannelRead(A);
                ctx.fireChannelRead(B);
            }
        };

        // channel
        EmbeddedChannel channel = new EmbeddedChannel(
                new ChannelInitializer<Channel>() {
                    @Override
                    protected void initChannel(Channel channel) throws Exception {
                        channel.pipeline().addLast(handler);
                    }
                }
        );

        assert handler == channel.pipeline().firstContext().handler();

        assert true ==  channel.writeInbound("C");

        assert true == channel.finish();

        assert A.equals(channel.readInbound());

        assert B.equals(channel.readInbound());

Scheduling

        EmbeddedChannel ch = new EmbeddedChannel(new ChannelInboundHandlerAdapter());
        final CountDownLatch latch = new CountDownLatch(2);
        // future
        Future future = ch.eventLoop().schedule(new Runnable() {
            @Override
            public void run() {
                System.out.println("future");
                latch.countDown();
            }
        }, 1, TimeUnit.SECONDS);
        // 监听future完成
        future.addListener(new FutureListener() {
            @Override
            public void operationComplete(Future future) throws Exception {
                System.out.println("operationComplete");
                latch.countDown();
            }
        });

        // run pending schedule task
        long next = ch.runScheduledPendingTasks();

        System.out.println(next);
        assert next > 0;
        TimeUnit.NANOSECONDS.sleep(TimeUnit.NANOSECONDS.toMillis(next) + 66);
        assert  ch.runScheduledPendingTasks() == -1;
        System.out.println(next);
        latch.await();