io.netty.handler.codec.http2.Http2ChannelDuplexHandler Maven / Gradle / Ivy
/*
* Copyright 2016 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package io.netty.handler.codec.http2;
import io.netty.channel.ChannelDuplexHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPipeline;
import io.netty.util.internal.StringUtil;
/**
* A {@link ChannelDuplexHandler} providing additional functionality for HTTP/2. Specifically it allows to:
*
* - Create new outbound streams using {@link #newStream()}.
* - Iterate over all active streams using {@link #forEachActiveStream(Http2FrameStreamVisitor)}.
*
*
* The {@link Http2FrameCodec} is required to be part of the {@link ChannelPipeline} before this handler is added,
* or else an {@link IllegalStateException} will be thrown.
*/
public abstract class Http2ChannelDuplexHandler extends ChannelDuplexHandler {
private volatile Http2FrameCodec frameCodec;
@Override
public final void handlerAdded(ChannelHandlerContext ctx) throws Exception {
frameCodec = requireHttp2FrameCodec(ctx);
handlerAdded0(ctx);
}
protected void handlerAdded0(@SuppressWarnings("unused") ChannelHandlerContext ctx) throws Exception {
// NOOP
}
@Override
public final void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
try {
handlerRemoved0(ctx);
} finally {
frameCodec = null;
}
}
protected void handlerRemoved0(@SuppressWarnings("unused") ChannelHandlerContext ctx) throws Exception {
// NOOP
}
/**
* Creates a new {@link Http2FrameStream} object.
*
*
This method is thread-safe.
*/
public final Http2FrameStream newStream() {
Http2FrameCodec codec = frameCodec;
if (codec == null) {
throw new IllegalStateException(StringUtil.simpleClassName(Http2FrameCodec.class) + " not found." +
" Has the handler been added to a pipeline?");
}
return codec.newStream();
}
/**
* Allows to iterate over all currently active streams.
*
*
This method may only be called from the eventloop thread.
*/
protected final void forEachActiveStream(Http2FrameStreamVisitor streamVisitor) throws Http2Exception {
frameCodec.forEachActiveStream(streamVisitor);
}
private static Http2FrameCodec requireHttp2FrameCodec(ChannelHandlerContext ctx) {
ChannelHandlerContext frameCodecCtx = ctx.pipeline().context(Http2FrameCodec.class);
if (frameCodecCtx == null) {
throw new IllegalArgumentException(Http2FrameCodec.class.getSimpleName()
+ " was not found in the channel pipeline.");
}
return (Http2FrameCodec) frameCodecCtx.handler();
}
}