Package org.playframework.netty
Class HandlerPublisher<T>
java.lang.Object
io.netty.channel.ChannelHandlerAdapter
io.netty.channel.ChannelInboundHandlerAdapter
io.netty.channel.ChannelDuplexHandler
org.playframework.netty.HandlerPublisher<T>
- All Implemented Interfaces:
io.netty.channel.ChannelHandler
,io.netty.channel.ChannelInboundHandler
,io.netty.channel.ChannelOutboundHandler
,org.reactivestreams.Publisher<T>
public class HandlerPublisher<T>
extends io.netty.channel.ChannelDuplexHandler
implements org.reactivestreams.Publisher<T>
Publisher for a Netty Handler.
This publisher supports only one subscriber.
All interactions with the subscriber are done from the handlers executor, hence, they provide the same happens before
semantics that Netty provides.
The handler publishes all messages that match the type as specified by the passed in class. Any non matching messages
are forwarded to the next handler.
The publisher will signal complete if it receives a channel inactive event.
The publisher will release any messages that it drops (for example, messages that are buffered when the subscriber
cancels), but other than that, it does not release any messages. It is up to the subscriber to release messages.
If the subscriber cancels, the publisher will send a close event up the channel pipeline.
All errors will short circuit the buffer, and cause publisher to immediately call the subscribers onError method,
dropping the buffer.
The publisher can be subscribed to or placed in a handler chain in any order.
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprivate class
(package private) static enum
Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler
io.netty.channel.ChannelHandler.Sharable
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate static final Object
Used for buffering a completion signal.private io.netty.channel.ChannelHandlerContext
private final io.netty.util.concurrent.EventExecutor
private final AtomicBoolean
Whether a subscriber has been provided.private final io.netty.util.internal.TypeParameterMatcher
private Throwable
private long
private HandlerPublisher.State
private org.reactivestreams.Subscriber
<? super T> -
Constructor Summary
ConstructorsConstructorDescriptionHandlerPublisher
(io.netty.util.concurrent.EventExecutor executor, Class<? extends T> subscriberMessageType) Create a handler publisher. -
Method Summary
Modifier and TypeMethodDescriptionprotected boolean
Returnstrue
if the given message should be handled.private boolean
addDemand
(long demand) protected void
Override to handle when a subscriber cancels the subscription.void
channelActive
(io.netty.channel.ChannelHandlerContext ctx) void
channelInactive
(io.netty.channel.ChannelHandlerContext ctx) void
channelRead
(io.netty.channel.ChannelHandlerContext ctx, Object message) void
channelReadComplete
(io.netty.channel.ChannelHandlerContext ctx) void
channelRegistered
(io.netty.channel.ChannelHandlerContext ctx) private void
cleanup()
Release all elements from the buffer.private void
complete()
void
exceptionCaught
(io.netty.channel.ChannelHandlerContext ctx, Throwable cause) private void
void
handlerAdded
(io.netty.channel.ChannelHandlerContext ctx) void
handlerRemoved
(io.netty.channel.ChannelHandlerContext ctx) private void
private void
provideChannelContext
(io.netty.channel.ChannelHandlerContext ctx) private void
provideSubscriber
(org.reactivestreams.Subscriber<? super T> subscriber) private void
publishMessage
(Object message) private void
private void
receivedDemand
(long demand) protected void
Override to intercept when demand is requested.void
private void
verifyRegisteredWithRightExecutor
(io.netty.channel.ChannelHandlerContext ctx) Methods inherited from class io.netty.channel.ChannelDuplexHandler
bind, close, connect, deregister, disconnect, flush, read, write
Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter
channelUnregistered, channelWritabilityChanged, userEventTriggered
Methods inherited from class io.netty.channel.ChannelHandlerAdapter
ensureNotSharable, isSharable
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Field Details
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executor
private final io.netty.util.concurrent.EventExecutor executor -
matcher
private final io.netty.util.internal.TypeParameterMatcher matcher -
buffer
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hasSubscriber
Whether a subscriber has been provided. This is used to detect whether two subscribers are subscribing simultaneously. -
state
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subscriber
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ctx
private io.netty.channel.ChannelHandlerContext ctx -
outstandingDemand
private long outstandingDemand -
noSubscriberError
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COMPLETE
Used for buffering a completion signal.
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Constructor Details
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HandlerPublisher
public HandlerPublisher(io.netty.util.concurrent.EventExecutor executor, Class<? extends T> subscriberMessageType) Create a handler publisher. The supplied executor must be the same event loop as the event loop that this handler is eventually registered with, if not, an exception will be thrown when the handler is registered.- Parameters:
executor
- The executor to execute asynchronous events from the subscriber on.subscriberMessageType
- The type of message this publisher accepts.
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Method Details
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acceptInboundMessage
Returnstrue
if the given message should be handled. Iffalse
it will be passed to the nextChannelInboundHandler
in theChannelPipeline
.- Parameters:
msg
- The message to check.- Returns:
- True if the message should be accepted.
- Throws:
Exception
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cancelled
protected void cancelled()Override to handle when a subscriber cancels the subscription. By default, this method will simply close the channel. -
requestDemand
protected void requestDemand()Override to intercept when demand is requested. By default, a channel read is invoked. -
subscribe
- Specified by:
subscribe
in interfaceorg.reactivestreams.Publisher<T>
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provideSubscriber
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handlerAdded
- Specified by:
handlerAdded
in interfaceio.netty.channel.ChannelHandler
- Overrides:
handlerAdded
in classio.netty.channel.ChannelHandlerAdapter
- Throws:
Exception
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channelRegistered
- Specified by:
channelRegistered
in interfaceio.netty.channel.ChannelInboundHandler
- Overrides:
channelRegistered
in classio.netty.channel.ChannelInboundHandlerAdapter
- Throws:
Exception
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provideChannelContext
private void provideChannelContext(io.netty.channel.ChannelHandlerContext ctx) -
verifyRegisteredWithRightExecutor
private void verifyRegisteredWithRightExecutor(io.netty.channel.ChannelHandlerContext ctx) -
channelActive
- Specified by:
channelActive
in interfaceio.netty.channel.ChannelInboundHandler
- Overrides:
channelActive
in classio.netty.channel.ChannelInboundHandlerAdapter
- Throws:
Exception
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receivedDemand
private void receivedDemand(long demand) -
addDemand
private boolean addDemand(long demand) -
illegalDemand
private void illegalDemand() -
flushBuffer
private void flushBuffer() -
receivedCancel
private void receivedCancel() -
channelRead
public void channelRead(io.netty.channel.ChannelHandlerContext ctx, Object message) throws Exception - Specified by:
channelRead
in interfaceio.netty.channel.ChannelInboundHandler
- Overrides:
channelRead
in classio.netty.channel.ChannelInboundHandlerAdapter
- Throws:
Exception
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publishMessage
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channelReadComplete
- Specified by:
channelReadComplete
in interfaceio.netty.channel.ChannelInboundHandler
- Overrides:
channelReadComplete
in classio.netty.channel.ChannelInboundHandlerAdapter
- Throws:
Exception
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channelInactive
- Specified by:
channelInactive
in interfaceio.netty.channel.ChannelInboundHandler
- Overrides:
channelInactive
in classio.netty.channel.ChannelInboundHandlerAdapter
- Throws:
Exception
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handlerRemoved
- Specified by:
handlerRemoved
in interfaceio.netty.channel.ChannelHandler
- Overrides:
handlerRemoved
in classio.netty.channel.ChannelHandlerAdapter
- Throws:
Exception
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complete
private void complete() -
exceptionCaught
public void exceptionCaught(io.netty.channel.ChannelHandlerContext ctx, Throwable cause) throws Exception - Specified by:
exceptionCaught
in interfaceio.netty.channel.ChannelHandler
- Specified by:
exceptionCaught
in interfaceio.netty.channel.ChannelInboundHandler
- Overrides:
exceptionCaught
in classio.netty.channel.ChannelInboundHandlerAdapter
- Throws:
Exception
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cleanup
private void cleanup()Release all elements from the buffer.
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