EchoHandler Class — netty Architecture

Source Code

testsuite/src/main/java/io/netty/testsuite/transport/socket/SocketEchoTest.java lines 254–311

    private static class EchoHandler extends SimpleChannelInboundHandler<ByteBuf> {
        private final boolean autoRead;
        volatile Channel channel;
        final AtomicReference<Throwable> exception = new AtomicReference<Throwable>();
        volatile int counter;

        EchoHandler(boolean autoRead) {
            this.autoRead = autoRead;
        }

        @Override
        public void channelActive(ChannelHandlerContext ctx)
                throws Exception {
            channel = ctx.channel();
            if (!autoRead) {
                ctx.read();
            }
        }

        @Override
        public void channelRead0(ChannelHandlerContext ctx, ByteBuf in) throws Exception {
            byte[] actual = new byte[in.readableBytes()];
            in.readBytes(actual);

            int lastIdx = counter;
            for (int i = 0; i < actual.length; i ++) {
                assertEquals(data[i + lastIdx], actual[i]);
            }

            // Update the counter before calling write(...) as write could in theory trigger another channelRead(...)
            // which then would use the wrong lastIdx.
            counter += actual.length;

            if (channel.parent() != null) {
                channel.write(randomBufferType(channel.alloc(), actual, 0, actual.length));
            }
        }

        @Override
        public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
            try {
                ctx.flush();
            } finally {
                if (!autoRead) {
                    ctx.read();
                }
            }
        }

        @Override
        public void exceptionCaught(ChannelHandlerContext ctx,
                Throwable cause) throws Exception {
            if (exception.compareAndSet(null, cause)) {
                cause.printStackTrace();
                ctx.close();
            }
        }
    }