Polishing

See gh-21798

spring-messaging/src/main/java/org/springframework/messaging/simp/SimpMessageHeaderAccessor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -273,7 +273,7 @@ public static SimpMessageHeaderAccessor create(SimpMessageType messageType) {
 	}
 
 	/**
-	 * Create an instance from the payload and headers of the given Message.
+	 * Create an instance by copying the headers of a Message.
 	 */
 	public static SimpMessageHeaderAccessor wrap(Message<?> message) {
 		return new SimpMessageHeaderAccessor(message);

spring-messaging/src/main/java/org/springframework/messaging/simp/user/DefaultUserDestinationResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -130,18 +130,17 @@ public UserDestinationResult resolveDestination(Message<?> message) {
 			return null;
 		}
 		String user = parseResult.getUser();
-		String sourceDestination = parseResult.getSourceDestination();
+		String sourceDest = parseResult.getSourceDestination();
 		Set<String> targetSet = new HashSet<>();
 		for (String sessionId : parseResult.getSessionIds()) {
-			String actualDestination = parseResult.getActualDestination();
-			String targetDestination = getTargetDestination(
-					sourceDestination, actualDestination, sessionId, user);
-			if (targetDestination != null) {
-				targetSet.add(targetDestination);
+			String actualDest = parseResult.getActualDestination();
+			String targetDest = getTargetDestination(sourceDest, actualDest, sessionId, user);
+			if (targetDest != null) {
+				targetSet.add(targetDest);
 			}
 		}
-		String subscribeDestination = parseResult.getSubscribeDestination();
-		return new UserDestinationResult(sourceDestination, targetSet, subscribeDestination, user);
+		String subscribeDest = parseResult.getSubscribeDestination();
+		return new UserDestinationResult(sourceDest, targetSet, subscribeDest, user);
 	}
 
 	@Nullable
@@ -283,22 +282,37 @@ public ParseResult(String sourceDest, String actualDest, String subscribeDest,
 			this.user = user;
 		}
 
+		/**
+		 * The destination from the source message, e.g. "/user/{user}/queue/position-updates".
+		 */
 		public String getSourceDestination() {
 			return this.sourceDestination;
 		}
 
+		/**
+		 * The actual destination, without any user prefix, e.g. "/queue/position-updates".
+		 */
 		public String getActualDestination() {
 			return this.actualDestination;
 		}
 
+		/**
+		 * The user destination as it would be on a subscription, "/user/queue/position-updates".
+		 */
 		public String getSubscribeDestination() {
 			return this.subscribeDestination;
 		}
 
+		/**
+		 * The session id or id's for the user.
+		 */
 		public Set<String> getSessionIds() {
 			return this.sessionIds;
 		}
 
+		/**
+		 * The name of the user associated with the session.
+		 */
 		@Nullable
 		public String getUser() {
 			return this.user;

spring-messaging/src/main/java/org/springframework/messaging/simp/user/UserDestinationMessageHandler.java

@@ -43,9 +43,9 @@
 /**
  * {@code MessageHandler} with support for "user" destinations.
  *
- * <p>Listens for messages with "user" destinations, translates their destination
- * to actual target destinations unique to the active session(s) of a user, and
- * then sends the resolved messages to the broker channel to be delivered.
+ * <p>Listen for messages with "user" destinations, translate the destination to
+ * a target destination that's unique to the active user session(s), and send
+ * to the broker channel for delivery.
  *
  * @author Rossen Stoyanchev
  * @since 4.0
@@ -75,24 +75,24 @@ public class UserDestinationMessageHandler implements MessageHandler, SmartLifec
 
 
 	/**
-	 * Create an instance with the given client and broker channels subscribing
-	 * to handle messages from each and then sending any resolved messages to the
-	 * broker channel.
+	 * Create an instance with the given client and broker channels to subscribe to,
+	 * and then send resolved messages to the broker channel.
 	 * @param clientInboundChannel messages received from clients.
 	 * @param brokerChannel messages sent to the broker.
-	 * @param resolver the resolver for "user" destinations.
+	 * @param destinationResolver the resolver for "user" destinations.
 	 */
-	public UserDestinationMessageHandler(SubscribableChannel clientInboundChannel,
-			SubscribableChannel brokerChannel, UserDestinationResolver resolver) {
+	public UserDestinationMessageHandler(
+			SubscribableChannel clientInboundChannel, SubscribableChannel brokerChannel,
+			UserDestinationResolver destinationResolver) {
 
 		Assert.notNull(clientInboundChannel, "'clientInChannel' must not be null");
 		Assert.notNull(brokerChannel, "'brokerChannel' must not be null");
-		Assert.notNull(resolver, "resolver must not be null");
+		Assert.notNull(destinationResolver, "resolver must not be null");
 
 		this.clientInboundChannel = clientInboundChannel;
 		this.brokerChannel = brokerChannel;
 		this.messagingTemplate = new SimpMessagingTemplate(brokerChannel);
-		this.destinationResolver = resolver;
+		this.destinationResolver = destinationResolver;
 	}
 
 
@@ -182,16 +182,16 @@ public final boolean isRunning() {
 
 
 	@Override
-	public void handleMessage(Message<?> message) throws MessagingException {
-		Message<?> messageToUse = message;
+	public void handleMessage(Message<?> sourceMessage) throws MessagingException {
+		Message<?> message = sourceMessage;
 		if (this.broadcastHandler != null) {
-			messageToUse = this.broadcastHandler.preHandle(message);
-			if (messageToUse == null) {
+			message = this.broadcastHandler.preHandle(sourceMessage);
+			if (message == null) {
 				return;
 			}
 		}
 
-		UserDestinationResult result = this.destinationResolver.resolveDestination(messageToUse);
+		UserDestinationResult result = this.destinationResolver.resolveDestination(message);
 		if (result == null) {
 			return;
 		}
@@ -201,22 +201,22 @@ public void handleMessage(Message<?> message) throws MessagingException {
 				logger.trace("No active sessions for user destination: " + result.getSourceDestination());
 			}
 			if (this.broadcastHandler != null) {
-				this.broadcastHandler.handleUnresolved(messageToUse);
+				this.broadcastHandler.handleUnresolved(message);
 			}
 			return;
 		}
 
-		SimpMessageHeaderAccessor accessor = SimpMessageHeaderAccessor.wrap(messageToUse);
+		SimpMessageHeaderAccessor accessor = SimpMessageHeaderAccessor.wrap(message);
 		initHeaders(accessor);
 		accessor.setNativeHeader(SimpMessageHeaderAccessor.ORIGINAL_DESTINATION, result.getSubscribeDestination());
 		accessor.setLeaveMutable(true);
 
-		messageToUse = MessageBuilder.createMessage(messageToUse.getPayload(), accessor.getMessageHeaders());
+		message = MessageBuilder.createMessage(message.getPayload(), accessor.getMessageHeaders());
 		if (logger.isTraceEnabled()) {
 			logger.trace("Translated " + result.getSourceDestination() + " -> " + result.getTargetDestinations());
 		}
 		for (String target : result.getTargetDestinations()) {
-			this.messagingTemplate.send(target, messageToUse);
+			this.messagingTemplate.send(target, message);
 		}
 	}
 

spring-messaging/src/test/java/org/springframework/messaging/simp/stomp/StompBrokerRelayMessageHandlerTests.java

@@ -54,11 +54,11 @@ class StompBrokerRelayMessageHandlerTests {
 
 	private StompBrokerRelayMessageHandler brokerRelay;
 
-	private StubMessageChannel outboundChannel = new StubMessageChannel();
+	private final StubMessageChannel outboundChannel = new StubMessageChannel();
 
-	private StubTcpOperations tcpClient = new StubTcpOperations();
+	private final StubTcpOperations tcpClient = new StubTcpOperations();
 
-	private ArgumentCaptor<Runnable> messageCountTaskCaptor = ArgumentCaptor.forClass(Runnable.class);
+	private final ArgumentCaptor<Runnable> messageCountTaskCaptor = ArgumentCaptor.forClass(Runnable.class);
 
 
 	@BeforeEach

spring-messaging/src/test/java/org/springframework/messaging/simp/user/UserDestinationMessageHandlerTests.java

@@ -23,6 +23,7 @@
 import org.mockito.Mockito;
 
 import org.springframework.core.testfixture.security.TestPrincipal;
+import org.springframework.lang.Nullable;
 import org.springframework.messaging.Message;
 import org.springframework.messaging.StubMessageChannel;
 import org.springframework.messaging.SubscribableChannel;
@@ -50,7 +51,8 @@ class UserDestinationMessageHandlerTests {
 
 	private final SubscribableChannel brokerChannel = mock();
 
-	private final UserDestinationMessageHandler handler = new UserDestinationMessageHandler(new StubMessageChannel(), this.brokerChannel, new DefaultUserDestinationResolver(this.registry));
+	private final UserDestinationMessageHandler handler = new UserDestinationMessageHandler(
+			new StubMessageChannel(), this.brokerChannel, new DefaultUserDestinationResolver(this.registry));
 
 
 	@Test
@@ -184,7 +186,9 @@ void ignoreMessage() {
 	}
 
 
-	private Message<?> createWith(SimpMessageType type, String user, String sessionId, String destination) {
+	private Message<?> createWith(
+			SimpMessageType type, @Nullable String user, @Nullable String sessionId, @Nullable String destination) {
+
 		SimpMessageHeaderAccessor headers = SimpMessageHeaderAccessor.create(type);
 		if (destination != null) {
 			headers.setDestination(destination);

spring-websocket/src/main/java/org/springframework/web/socket/messaging/StompSubProtocolHandler.java

@@ -108,9 +108,8 @@ public class StompSubProtocolHandler implements SubProtocolHandler, ApplicationE
 	@Nullable
 	private MessageHeaderInitializer headerInitializer;
 
-	private boolean preserveReceiveOrder;
-
-	private final Map<String, MessageChannel> messageChannels = new ConcurrentHashMap<>();
+	@Nullable
+	private Map<String, MessageChannel> orderedHandlingMessageChannels;
 
 	private final Map<String, Principal> stompAuthentications = new ConcurrentHashMap<>();
 
@@ -209,7 +208,7 @@ public MessageHeaderInitializer getHeaderInitializer() {
 	 * @since 6.1
 	 */
 	public void setPreserveReceiveOrder(boolean preserveReceiveOrder) {
-		this.preserveReceiveOrder = preserveReceiveOrder;
+		this.orderedHandlingMessageChannels = (preserveReceiveOrder ? new ConcurrentHashMap<>() : null);
 	}
 
 	/**
@@ -218,7 +217,7 @@ public void setPreserveReceiveOrder(boolean preserveReceiveOrder) {
 	 * @since 6.1
 	 */
 	public boolean isPreserveReceiveOrder() {
-		return this.preserveReceiveOrder;
+		return (this.orderedHandlingMessageChannels != null);
 	}
 
 	@Override
@@ -253,7 +252,7 @@ public Stats getStats() {
 	 */
 	@Override
 	public void handleMessageFromClient(WebSocketSession session,
-			WebSocketMessage<?> webSocketMessage, MessageChannel outputChannel) {
+			WebSocketMessage<?> webSocketMessage, MessageChannel targetChannel) {
 
 		List<Message<byte[]>> messages;
 		try {
@@ -296,11 +295,11 @@ else if (webSocketMessage instanceof BinaryMessage binaryMessage) {
 			return;
 		}
 
-		MessageChannel channelToUse =
-				(this.messageChannels.computeIfAbsent(session.getId(),
-						id -> this.preserveReceiveOrder ?
-								new OrderedMessageChannelDecorator(outputChannel, logger) :
-								outputChannel));
+		MessageChannel channelToUse = targetChannel;
+		if (this.orderedHandlingMessageChannels != null) {
+			channelToUse = this.orderedHandlingMessageChannels.computeIfAbsent(
+					session.getId(), id -> new OrderedMessageChannelDecorator(targetChannel, logger));
+		}
 
 		for (Message<byte[]> message : messages) {
 			StompHeaderAccessor headerAccessor =
@@ -324,7 +323,7 @@ else if (webSocketMessage instanceof BinaryMessage binaryMessage) {
 					});
 				}
 				headerAccessor.setHeader(SimpMessageHeaderAccessor.HEART_BEAT_HEADER, headerAccessor.getHeartbeat());
-				if (!detectImmutableMessageInterceptor(outputChannel)) {
+				if (!detectImmutableMessageInterceptor(targetChannel)) {
 					headerAccessor.setImmutable();
 				}
 
@@ -686,7 +685,9 @@ public void afterSessionEnded(WebSocketSession session, CloseStatus closeStatus,
 			outputChannel.send(message);
 		}
 		finally {
-			this.messageChannels.remove(session.getId());
+			if (this.orderedHandlingMessageChannels != null) {
+				this.orderedHandlingMessageChannels.remove(session.getId());
+			}
 			this.stompAuthentications.remove(session.getId());
 			SimpAttributesContextHolder.resetAttributes();
 			simpAttributes.sessionCompleted();