This version is still in development and is not considered stable yet. For the latest stable version, please use Spring Integration 6.3.2! |
TCP Connection Events
Beginning with version 3.0, changes to TcpConnection
instances are reported by TcpConnectionEvent
instances.
TcpConnectionEvent
is a subclass of ApplicationEvent
and can thus be received by any ApplicationListener
defined in the ApplicationContext
, or an @EventListener
method.
Also see an event inbound channel adapter.
TcpConnectionEvents
have the following properties:
-
connectionId
: The connection identifier, which you can use in a message header to send data to the connection. -
connectionFactoryName
: The bean name of the connection factory to which the connection belongs. -
throwable
: TheThrowable
(forTcpConnectionExceptionEvent
events only). -
source
: TheTcpConnection
. You can use this, for example, to determine the remote IP Address withgetHostAddress()
(cast required).
Available TcpConnectionEvent
s, related to a specific connection include:
-
TcpConnectionOpenEvent
-
TcpConnectionCloseEvent
-
TcpConnectionExceptionEvent
In addition, since version 4.0, the standard deserializers discussed in TCP Connection Factories now emit TcpDeserializationExceptionEvent
instances when they encounter problems while decoding the data stream.
These events contain the exception, the buffer that was in the process of being built, and an offset into the buffer (if available) at the point where the exception occurred.
Applications can use a normal ApplicationListener
, an @EventListener
method, or an ApplicationEventListeningMessageProducer
(see Receiving Spring Application Events) to capture these events, allowing analysis of the problem.
Starting with versions 4.0.7 and 4.1.3, TcpConnectionServerExceptionEvent
instances are published whenever an unexpected exception occurs on a server socket (such as a BindException
when the server socket is in use).
These events have a reference to the connection factory and the cause.
Starting with version 4.2, TcpConnectionFailedCorrelationEvent
instances are published whenever an endpoint (inbound gateway or collaborating outbound channel adapter) receives a message that cannot be routed to a connection because the ip_connectionId
header is invalid.
Outbound gateways also publish this event when a late reply is received (the sender thread has timed out).
The event contains the connection ID as well as an exception in the cause
property, which contains the failed message.
Starting with version 4.3, a TcpConnectionServerListeningEvent
is emitted when a server connection factory is started.
This is useful when the factory is configured to listen on port 0
, meaning that the operating system chooses the port.
It can also be used instead of polling isListening()
, if you need to wait before starting some other process that connects to the socket.
To avoid delaying the listening thread from accepting connections, the event is published on a separate thread. |
Starting with version 4.3.2, a TcpConnectionFailedEvent
is emitted whenever a client connection cannot be created.
The source of the event is the connection factory, which you can use to determine the host and port to which the connection could not be established.
To use a single ApplicationListener
(or @EventListener
method) to receive all of these events (including TcpConnectionEvent
s), configure the listener to receive IpIntegrationEvent
s.