Motivation:
Usually the outbound operation should start at the "current" ChanneöHandlercontext which was often not the case
Modifications:
Use the ChannelHandlerContext for closing the connection
Result:
Start the operation on the right position of the pipeline
Motivation:
The generics for the existing futures, promises, and listeners are too complicated.
This complication comes from the existence of `ChannelPromise` and `ChannelFuture`, which forces listeners to care about the particular _type_ of future being listened on.
Modification:
* Add a `FutureContextListener` which can take a context object as an additional argument. This allows our listeners to have the channel piped through to them, so they don't need to rely on the `ChannelFuture.channel()` method.
* Make the `FutureListener`, along with the `FutureContextListener` sibling, the default listener API, retiring the `GenericFutureListener` since we no longer need to abstract over the type of the future.
* Change all uses of `ChannelPromise` to `Promise<Void>`.
* Change all uses of `ChannelFuture` to `Future<Void>`.
* Change all uses of `GenericFutureListener` to either `FutureListener` or `FutureContextListener` as needed.
* Remove `ChannelFutureListener` and `GenericFutureListener`.
* Introduce a `ChannelFutureListeners` enum to house the constants that previously lived in `ChannelFutureListener`. These constants now implement `FutureContextListener` and take the `Channel` as a context.
* Remove `ChannelPromise` and `ChannelFuture` — all usages now rely on the plain `Future` and `Promise` APIs.
* Add static factory methods to `DefaultPromise` that allow us to create promises that are initialised as successful or failed.
* Remove `CompleteFuture`, `SucceededFuture`, `FailedFuture`, `CompleteChannelFuture`, `SucceededChannelFuture`, and `FailedChannelFuture`.
* Remove `ChannelPromiseNotifier`.
Result:
Cleaner generics and more straight forward code.
Bootstrap methods now return Future<Channel> instead of ChannelFuture
Motivation:
In #8516 it was proposed to at some point remove the specialised ChannelFuture and ChannelPromise.
Or at least make them not extend Future and Promise, respectively.
One pain point encountered in this discussion is the need to get access to the channel object after it has been initialised, but without waiting for the channel registration to propagate through the pipeline.
Modification:
Add a Bootstrap.createUnregistered method, which will return a Channel directly.
All other Bootstrap methods that previously returned ChannelFuture now return Future<Channel>
Result:
It's now possible to obtain an initialised but unregistered channel from a bootstrap, without blocking.
And the other bootstrap methods now only release their channels through the result of their futures, preventing racy access to the channels.
Motivation:
At the moment we only expose close(...) methods that take a Channel as paramater. This can be problematic as the write will start at the end of the pipeline which may contain ChannelOutboundHandler implementations that not expect WebSocketFrame objects. We should better also support to pass in a ChannelHandlerContext as starting point for the write which ensures that the WebSocketFrame objects will be handled correctly from this position of the pipeline.
Modifications:
- Add new close(...) methods that take a ChannelHandlerContext
- Add javadoc sentence to point users to the new methods.
Result:
Be able to "start" the close at the right position in the pipeline.
Motivation:
HTTP is a plaintext protocol which means that someone may be able
to eavesdrop the data. To prevent this, HTTPS should be used whenever
possible. However, maintaining using https:// in all URLs may be
difficult. The nohttp tool can help here. The tool scans all the files
in a repository and reports where http:// is used.
Modifications:
- Added nohttp (via checkstyle) into the build process.
- Suppressed findings for the websites
that don't support HTTPS or that are not reachable
Result:
- Prevent using HTTP in the future.
- Encourage users to use HTTPS when they follow the links they found in
the code.
Motivation:
In next major version of netty users should use ChannelHandler everywhere. We should ensure we do the same
Modifications:
Replace usage of deprecated classes / interfaces with ChannelHandler
Result:
Use non-deprecated code
Motivation:
In many places Netty uses Unpooled.buffer(0) while should use EMPTY_BUFFER. We can't change this due to back compatibility in the constructors but can use Unpooled.EMPTY_BUFFER in some cases to ensure we not allocate at all. In others we can directly use the allocator either from the Channel / ChannelHandlerContext or the request / response.
Modification:
- Use Unpooled.EMPTY_BUFFER where possible
- Use allocator where possible
Result:
Fixes#9345 for websockets and http package
Motivation:
As we now us java8 as minimum java version we can deprecate ChannelInboundHandlerAdapter / ChannelOutboundHandlerAdapter and just move the default implementations into the interfaces. This makes things a bit more flexible for the end-user and also simplifies the class-hierarchy.
Modifications:
- Mark ChannelInboundHandlerAdapter and ChannelOutboundHandlerAdapter as deprecated
- Add default implementations to ChannelInboundHandler / ChannelOutboundHandler
- Refactor our code to not use ChannelInboundHandlerAdapter / ChannelOutboundHandlerAdapter anymore
Result:
Cleanup class-hierarchy and make things a bit more flexible.
Motivation:
In most cases, HttpMethod instance is built from the factory method and the same instance is taken for known Http Methods. So we can implement fast path for equals().
Modification:
Replace == checks with HttpMethod.equals;
Use this == o within HttpMethod.equals;
Replaced known new HttpMethod with HttpMethod.valueOf;
Result:
Comparisons should be a bit faster in some cases.
* Decouble EventLoop details from the IO handling for each transport to allow easy re-use of code and customization
Motiviation:
As today extending EventLoop implementations to add custom logic / metrics / instrumentations is only possible in a very limited way if at all. This is due the fact that most implementations are final or even package-private. That said even if these would be public there are the ability to do something useful with these is very limited as the IO processing and task processing are very tightly coupled. All of the mentioned things are a big pain point in netty 4.x and need improvement.
Modifications:
This changeset decoubled the IO processing logic from the task processing logic for the main transport (NIO, Epoll, KQueue) by introducing the concept of an IoHandler. The IoHandler itself is responsible to wait for IO readiness and process these IO events. The execution of the IoHandler itself is done by the SingleThreadEventLoop as part of its EventLoop processing. This allows to use the same EventLoopGroup (MultiThreadEventLoupGroup) for all the mentioned transports by just specify a different IoHandlerFactory during construction.
Beside this core API change this changeset also allows to easily extend SingleThreadEventExecutor / SingleThreadEventLoop to add custom logic to it which then can be reused by all the transports. The ideas are very similar to what is provided by ScheduledThreadPoolExecutor (that is part of the JDK). This allows for example things like:
* Adding instrumentation / metrics:
* how many Channels are registered on an SingleThreadEventLoop
* how many Channels were handled during the IO processing in an EventLoop run
* how many task were handled during the last EventLoop / EventExecutor run
* how many outstanding tasks we have
...
...
* Implementing custom strategies for choosing the next EventExecutor / EventLoop to use based on these metrics.
* Use different Promise / Future / ScheduledFuture implementations
* decorate Runnable / Callables when submitted to the EventExecutor / EventLoop
As a lot of functionalities are folded into the MultiThreadEventLoopGroup and SingleThreadEventLoopGroup this changeset also removes:
* AbstractEventLoop
* AbstractEventLoopGroup
* EventExecutorChooser
* EventExecutorChooserFactory
* DefaultEventLoopGroup
* DefaultEventExecutor
* DefaultEventExecutorGroup
Result:
Fixes https://github.com/netty/netty/issues/8514 .
Motivation:
We should move the AutobahnTestsuite to an extra module. This allows easier to run only the testsuite or only the autobahntestsuite
Modifications:
Create a new module (testsuite-autobahn)
Result:
Better project structure.
