Spring Framework 6.1.4 · org.springframework.messaging.simp.stomp.StompBrokerRelayMessageHandler

A org.springframework.messaging.MessageHandler that handles messages by forwarding them to a STOMP broker.

For each new CONNECT message, an independent TCP connection to the broker is opened and used exclusively for all messages from the client that originated the CONNECT message. Messages from the same client are identified through the session id message header. Reversely, when the STOMP broker sends messages back on the TCP connection, those messages are enriched with the session id of the client and sent back downstream through the MessageChannel provided to the constructor.

This class also automatically opens a default "system" TCP connection to the message broker that is used for sending messages that originate from the server application (as opposed to from a client). Such messages are not associated with any client and therefore do not have a session id header. The "system" connection is effectively shared and cannot be used to receive messages. Several properties are provided to configure the "system" connection including:

Modifier and Type	Class and Description
private class	StompBrokerRelayMessageHandler.ClientSendMessageCountTask
private class	StompBrokerRelayMessageHandler.DefaultStats
private class	StompBrokerRelayMessageHandler.RelayConnectionHandler
public static interface	StompBrokerRelayMessageHandler.Stats Contract for access to session counters.
private class	StompBrokerRelayMessageHandler.SystemSessionConnectionHandler

Modifier and Type	Field and Description
private String	clientLogin
private String	clientPasscode
private final Map<String, StompBrokerRelayMessageHandler.RelayConnectionHandler>	connectionHandlers
private static final byte[]	EMPTY_PAYLOAD
private static final CompletableFuture<Void>	EMPTY_TASK
private MessageHeaderInitializer	headerInitializer
private static final StompHeaderAccessor	HEART_BEAT_ACCESSOR
private static final Message<byte[]>	HEARTBEAT_MESSAGE
private static final long	HEARTBEAT_MULTIPLIER STOMP recommended error of margin for receiving heartbeats.
private static final int	MAX_TIME_TO_CONNECTED_FRAME Heartbeat starts once CONNECTED frame with heartbeat settings is received.
private static final boolean	reactorNetty2ClientPresent
private static final boolean	reactorNettyClientPresent
private String	relayHost
private int	relayPort
private final StompBrokerRelayMessageHandler.DefaultStats	stats
public static final String	SYSTEM_SESSION_ID The system session ID.
private long	systemHeartbeatReceiveInterval
private long	systemHeartbeatSendInterval
private String	systemLogin
private String	systemPasscode
private final Map<String, MessageHandler>	systemSubscriptions
private TaskScheduler	taskScheduler
private TcpOperations<byte[]>	tcpClient
private String	virtualHost

Access	Constructor and Description
public	StompBrokerRelayMessageHandler(SubscribableChannel the channel for receiving messages from clients (e.g. WebSocket clients) inboundChannel, MessageChannel the channel for sending messages to clients (e.g. WebSocket clients) outboundChannel, SubscribableChannel the channel for the application to send messages to the broker brokerChannel, Collection<String> the broker supported destination prefixes; destinations that do not match the given prefix are ignored. destinationPrefixes) Create a StompBrokerRelayMessageHandler instance with the given message channels and destination prefixes.

Method Summary

Modifier and Type	Method and Description
public String	getClientLogin() Return the configured login to use for connections to the STOMP broker on behalf of connected clients.
public String	getClientPasscode() Return the configured passcode to use for connections to the STOMP broker on behalf of connected clients.
public int	getConnectionCount() Return the current count of TCP connection to the broker.
public MessageHeaderInitializer	getHeaderInitializer() Return the configured header initializer.
public String	getRelayHost() Return the STOMP message broker host.
public int	getRelayPort() Return the STOMP message broker port.
public StompBrokerRelayMessageHandler.Stats	getStats() Return a structured object with internal state and counters.
public String	getStatsInfo() Return a String describing internal state and counters.
public long	getSystemHeartbeatReceiveInterval() Return the interval, in milliseconds, at which the "system" connection expects to receive heartbeats from the STOMP broker.
public long	getSystemHeartbeatSendInterval() Return the interval, in milliseconds, at which the "system" connection will send heartbeats to the STOMP broker.
public String	getSystemLogin() Return the login used for the shared "system" connection to the STOMP broker.
public String	getSystemPasscode() Return the passcode used for the shared "system" connection to the STOMP broker.
public Map<String, MessageHandler>	getSystemSubscriptions() Return the configured map with subscriptions on the "system" connection.
public TaskScheduler	getTaskScheduler()
public TcpOperations<byte[]>	getTcpClient() Get the configured TCP client (never `null` unless not configured invoked and this method is invoked before the handler is started and hence a default implementation initialized).
private String	getTcpClientInfo()
public String	getVirtualHost() Return the configured virtual host value.
protected void	handleMessageInternal(Message<?> message) Implements abstract org.springframework.messaging.simp.broker.AbstractBrokerMessageHandler.handleMessageInternal.
private TcpOperations<byte[]>	initTcpClient()
public void	setClientLogin(String clientLogin) Set the login to use when creating connections to the STOMP broker on behalf of connected clients.
public void	setClientPasscode(String clientPasscode) Set the client passcode to use to create connections to the STOMP broker on behalf of connected clients.
public void	setHeaderInitializer(MessageHeaderInitializer headerInitializer) Configure a `MessageHeaderInitializer` to apply to the headers of all messages created through the `StompBrokerRelayMessageHandler` that are sent to the client outbound message channel.
public void	setRelayHost(String relayHost) Set the STOMP message broker host.
public void	setRelayPort(int relayPort) Set the STOMP message broker port.
public void	setSystemHeartbeatReceiveInterval(long heartbeatReceiveInterval) Set the maximum interval, in milliseconds, at which the "system" connection expects, in the absence of any other data, to receive a heartbeat from the STOMP broker.
public void	setSystemHeartbeatSendInterval(long systemHeartbeatSendInterval) Set the interval, in milliseconds, at which the "system" connection will, in the absence of any other data being sent, send a heartbeat to the STOMP broker.
public void	setSystemLogin(String systemLogin) Set the login for the shared "system" connection used to send messages to the STOMP broker from within the application, i.e. messages not associated with a specific client session (e.g. REST/HTTP request handling method).
public void	setSystemPasscode(String systemPasscode) Set the passcode for the shared "system" connection used to send messages to the STOMP broker from within the application, i.e. messages not associated with a specific client session (e.g. REST/HTTP request handling method).
public void	setSystemSubscriptions(Map<String, MessageHandler> the destinations to subscribe to. subscriptions) Configure one more destinations to subscribe to on the shared "system" connection along with MessageHandler's to handle received messages.
public void	setTaskScheduler(TaskScheduler the scheduler to use taskScheduler) Configure the `TaskScheduler` to use to reset client-to-broker message count in the current heartbeat period.
public void	setTcpClient(TcpOperations<byte[]> tcpClient) Configure a TCP client for managing TCP connections to the STOMP broker.
public void	setVirtualHost(String virtualHost) Set the value of the "host" header to use in STOMP CONNECT frames.
protected void	startInternal() Overrides org.springframework.messaging.simp.broker.AbstractBrokerMessageHandler.startInternal.
protected void	stopInternal() Overrides org.springframework.messaging.simp.broker.AbstractBrokerMessageHandler.stopInternal.
public String	toString() Overrides java.lang.Object.toString. Returns a string representation of the object.

public Class StompBrokerRelayMessageHandler

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