FailureTestHandler Class — netty Architecture

Source Code

handler-proxy/src/test/java/io/netty/handler/proxy/ProxyHandlerTest.java lines 559–606

    private static final class FailureTestHandler extends SimpleChannelInboundHandler<Object> {

        final Queue<Throwable> exceptions = new LinkedBlockingQueue<Throwable>();

        /**
         * A latch that counts down when:
         * - a pending write attempt in {@link #channelActive(ChannelHandlerContext)} finishes, or
         * - the channel is closed.
         * By waiting until the latch goes down to 0, we can make sure all assertion failures related with all write
         * attempts have been recorded.
         */
        final CountDownLatch latch = new CountDownLatch(2);

        @Override
        public void channelActive(ChannelHandlerContext ctx) throws Exception {
            ctx.writeAndFlush(Unpooled.copiedBuffer("A\n", CharsetUtil.US_ASCII)).addListener(
                    future -> {
                        latch.countDown();
                        if (!(future.cause() instanceof ProxyConnectException)) {
                            exceptions.add(new AssertionError(
                                    "Unexpected failure cause for initial write: " + future.cause()));
                        }
                    });
        }

        @Override
        public void channelInactive(ChannelHandlerContext ctx) throws Exception {
            latch.countDown();
        }

        @Override
        public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
            if (evt instanceof ProxyConnectionEvent) {
                fail("Unexpected event: " + evt);
            }
        }

        @Override
        protected void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
            fail("Unexpected message: " + msg);
        }

        @Override
        public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
            exceptions.add(cause);
            ctx.close();
        }
    }