@Sharable should also support @Target(ElementType.TYPE_USE)

Expected behavior

@Sharable should also be usable with anonymous inner types, so that it is no longer necessary to make named classes (top-level or nested) for sharable handlers. Since Java 8, this is possible with the new ElementType TYPE_USE. The practical problem here is that either (a) Netty would have to, at some point, require Java 8 (don’t think that’s the case yet), or (b) an additional Java-8-specific @Sharable annotation would have to be introduced.

Actual behavior

@Sharable only targets ElementType TYPE and requires a proper (i.e., named) class.

Steps to reproduce

Add @Sharable annotation to inner class, observe compilation error.

Minimal yet complete reproducer code (or URL to code)

ChannelInboundHandler echoHandler = new @Sharable ChannelInboundHandlerAdapter() {
      @Override
      public void channelRead(ChannelHandlerContext context, Object message) {
           context.write(message);
      }
}

Netty version

4.1.22.Final

JVM version (e.g. java -version)

1.8.0_152

OS version (e.g. uname -a)

Darwin Kernel Version 16.7.0: Wed Oct 4 00:17:00 PDT 2017; root:xnu-3789.71.6~1/RELEASE_X86_64 x86_64 (MacOS 10.12.6)

[kiril-me]

I can work on that.

[normanmaurer]

@kiril-me thanks a lot for all the help!