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Polish STOMP documentation

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Rossen Stoyanchev
2014-04-28 22:35:10 -04:00
parent 77a250ef92
commit 26a9c4bc01
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@@ -37749,61 +37749,51 @@ sections <<websocket-stomp-handle-broker-relay-configure>> and
[[websocket-stomp-message-flow]]
==== Flow of Messages
When a STOMP endpoint is configured, the Spring application becomes the broker to
connected clients. It handles incoming messages and broadcasts messages back.
This section provides the big picture of how messages are handled and how
they flow inside the application.
When a STOMP endpoint is configured, the Spring application acts as the STOMP broker
to connected clients. It handles incoming messages and sends messages back.
This section provides a big picture overview of how messages flow inside the application.
The `spring-messaging` module contains a number of abstractions for use in
messaging applications which originated in the
https://spring.io/spring-integration[Spring Integration] project and
have been in use for a long time but are now part of the Spring Framework.
Listed below are some of the main building blocks:
The `spring-messaging` module contains a number of abstractions that originated in the
https://spring.io/spring-integration[Spring Integration] project and are intended
for use as building blocks in messaging applications:
* {javadoc-baseurl}/org/springframework/messaging/Message.html[Message]
* {javadoc-baseurl}/org/springframework/messaging/Message.html[Message] --
represents a message with headers and a payload.
* {javadoc-baseurl}/org/springframework/messaging/MessageHandler.html[MessageHandler]
a simple contract components that handle a message.
* {javadoc-baseurl}/org/springframework/messaging/MessageChannel.html[MessageChannel]
a simple contract for sending a message that enables loose coupling between
senders and receivers.
* {javadoc-baseurl}/org/springframework/messaging/SubscribableChannel.html[SubscribableChannel]
* {javadoc-baseurl}/org/springframework/messaging/MessageHandler.html[MessageHandler] --
a contract for handling a message.
* {javadoc-baseurl}/org/springframework/messaging/MessageChannel.html[MessageChannel] --
a contract for sending a message enabling loose coupling between senders and receivers.
* {javadoc-baseurl}/org/springframework/messaging/SubscribableChannel.html[SubscribableChannel] --
extends `MessageChannel` and sends messages to registered `MessageHandler` subscribers.
* {javadoc-baseurl}/org/springframework/messaging/support/ExecutorSubscribableChannel.html[ExecutorSubscribableChannel]
* {javadoc-baseurl}/org/springframework/messaging/support/ExecutorSubscribableChannel.html[ExecutorSubscribableChannel] --
a concrete implementation of `SubscribableChannel` that can deliver messages
asynchronously using threads from a thread pool.
asynchronously through a thread pool.
The above building blocks can be used to construct a message flow.
The provided STOMP over WebSocket config, both Java and XML, uses the above to
assemble a concrete message flow including the following 3 channels:
The provided configuration for STOMP over WebSocket, both Java config and XML namespace,
assemble just such a concrete message flow that consists of the following 3
subscribable channels:
* `"clientInboundChannel"` -- for messages from WebSocket clients. Every incoming
WebSocket message carrying a STOMP frame is sent through this channel.
* `"clientOutboundChannel"` -- for messages to WebSocket clients. Every outgoing
STOMP message from the broker is sent through this channel before getting sent
to a client's WebSocket session.
* `"brokerChannel"` -- for messages to the broker from within the application.
Every message sent from the application to the broker passes through this channel.
* `"clientInboundChannel"` for messages from WebSocket clients; every incoming
WebSocket message that is decoded and turned into a Spring Message representing
a STOMP frame is passed through this channel.
* `"clientOutboundChannel"` for messages to WebSocket clients; every outgoing
Spring Message representing a STOMP frame that is encoded and sent as a
WebSocket message is passed through this channel.
* `"brokerChannel"` for messages to the broker from within the application and
ultimately intended to reach connected clients; every message that the application
wants to send to clients passes through this channel.
Messages through `"clientInboundChannel"` can flow to annotated
Messages on the `"clientInboundChannel"` can flow to annotated
methods for application handling (e.g. a stock trade execution request) or can
be forwarded to the broker (e.g. client subscribing for stock quotes).
The STOMP destination is used for simple prefix-based routing. For example
the "/app" prefix routes messages annotated methods while the "/topic" or
"/queue" prefix route messages to the broker.
the "/app" prefix could route messages to annotated methods while the "/topic"
and "/queue" prefixes could route messages to the broker.
When a message-handling annotated method has a return type, its return
value is sent as the payload of a Spring Message to the `"brokerChannel"`.
The broker in turn broadcasts the message to clients. Sending an object as
the payload of a Message to a specific destination can also easily be done
from anywhere in the application with the help of a messaging template.
For example a an HTTP POST handling method can broadcast a message to
connected clients or a service component may periodically broadcast
stock quotes.
The broker in turn broadcasts the message to clients. Sending a message
to a destination can also be done from anywhere in the application with
the help of a messaging template. For example a an HTTP POST handling method
can broadcast a message to connected clients or a service component may
periodically broadcast stock quotes.
Below is a simple example to illustrate the flow of messages:
@@ -37839,7 +37829,7 @@ Below is a simple example to illustrate the flow of messages:
----
The following explains how messages flow given the above:
The following explains the message flow for the above exmaple:
* WebSocket clients connect to the WebSocket endpoint at "/portfolio".
* Subscriptions to "/topic/greeting" pass through the "clientInboundChannel"