More docs for new RSocket features

spring-integration-rsocket/src/main/java/org/springframework/integration/rsocket/IntegrationRSocketMessageHandler.java

@@ -54,8 +54,8 @@ class IntegrationRSocketMessageHandler extends RSocketMessageHandler {
 		this(false);
 	}
 
-	IntegrationRSocketMessageHandler(boolean requestMappingCompatible) {
-		this.messageMappingCompatible = requestMappingCompatible;
+	IntegrationRSocketMessageHandler(boolean messageMappingCompatible) {
+		this.messageMappingCompatible = messageMappingCompatible;
 		if (!this.messageMappingCompatible) {
 			setHandlerPredicate((clazz) -> false);
 		}

spring-integration-rsocket/src/main/java/org/springframework/integration/rsocket/ServerRSocketConnector.java

@@ -99,6 +99,10 @@ public class ServerRSocketConnector extends AbstractRSocketConnector implements
 		this.serverTransport = serverTransport;
 	}
 
+	private ServerRSocketMessageHandler serverRSocketMessageHandler() {
+		return (ServerRSocketMessageHandler) this.rSocketMessageHandler;
+	}
+
 	/**
 	 * Provide a {@link Consumer} to configure the {@link RSocketFactory.ServerRSocketFactory}.
 	 * @param factoryConfigurer the {@link Consumer} to configure the {@link RSocketFactory.ServerRSocketFactory}.
@@ -110,7 +114,7 @@ public class ServerRSocketConnector extends AbstractRSocketConnector implements
 
 	/**
 	 * Configure a strategy to determine a key for the client {@link RSocketRequester} connected.
-	 * Defaults to the {@code destination} the client is connected.
+	 * Defaults to the {@code destination} to which a client is connected.
 	 * @param clientRSocketKeyStrategy the {@link BiFunction} to determine a key for client {@link RSocketRequester}s.
 	 */
 	public void setClientRSocketKeyStrategy(BiFunction<Map<String, Object>,
@@ -172,15 +176,31 @@ public class ServerRSocketConnector extends AbstractRSocketConnector implements
 		}
 	}
 
+	/**
+	 * Return connected {@link RSocketRequester}s mapped by keys.
+	 * @return connected {@link RSocketRequester}s mapped by keys.
+	 * @see ServerRSocketMessageHandler#getClientRSocketRequesters()
+	 */
 	public Map<Object, RSocketRequester> getClientRSocketRequesters() {
 		return serverRSocketMessageHandler().getClientRSocketRequesters();
 	}
 
+	/**
+	 * Return connected {@link RSocketRequester} mapped by key or null.
+	 * @param key the mapping key.
+	 * @return the {@link RSocketRequester} or null.
+	 * @see ServerRSocketMessageHandler#getClientRSocketRequester(Object)
+	 */
 	@Nullable
 	public RSocketRequester getClientRSocketRequester(Object key) {
-		return getClientRSocketRequesters().get(key);
+		return serverRSocketMessageHandler().getClientRSocketRequester(key);
 	}
 
+	/**
+	 * Return the port this internal server is bound or empty {@link Mono}.
+	 * @return the port this internal server is bound or empty {@link Mono}
+	 * if an external server is used.
+	 */
 	public Mono<Integer> getBoundPort() {
 		if (this.serverTransport != null) {
 			return this.serverMono
@@ -191,10 +211,6 @@ public class ServerRSocketConnector extends AbstractRSocketConnector implements
 		}
 	}
 
-	private ServerRSocketMessageHandler serverRSocketMessageHandler() {
-		return (ServerRSocketMessageHandler) this.rSocketMessageHandler;
-	}
-
 	@Override
 	protected void doStart() {
 		if (this.serverTransport != null) {

spring-integration-rsocket/src/main/java/org/springframework/integration/rsocket/ServerRSocketMessageHandler.java

@@ -26,6 +26,7 @@ import java.util.function.BiFunction;
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.context.ApplicationEventPublisherAware;
 import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.lang.Nullable;
 import org.springframework.messaging.Message;
 import org.springframework.messaging.MessageHeaders;
 import org.springframework.messaging.handler.CompositeMessageCondition;
@@ -38,6 +39,18 @@ import org.springframework.util.ReflectionUtils;
 
 /**
  * An {@link IntegrationRSocketMessageHandler} extension for RSocket service side.
+ * <p>
+ * In a plain Spring Integration application instances of this class are created by the
+ * {@link ServerRSocketConnector} internally and a new RSocket server is started over there.
+ * When an existing RSocket server is in use, an instance of this class has to be
+ * provided as a {@link #responder()} into that server and a {@link ServerRSocketConnector}
+ * should accept the same instance as a delegate.
+ *<p>
+ * With a {@link #messageMappingCompatible} option this class also handles
+ * {@link org.springframework.messaging.handler.annotation.MessageMapping} methods,
+ * covering both Spring Integration and standard
+ * {@link org.springframework.messaging.rsocket.annotation.support.RSocketMessageHandler}
+ * functionality.
  *
  * @author Artem Bilan
  *
@@ -57,19 +70,35 @@ public class ServerRSocketMessageHandler extends IntegrationRSocketMessageHandle
 
 	private ApplicationEventPublisher applicationEventPublisher;
 
+	/**
+	 * Create an service side RSocket message handler instance for delegating
+	 * to {@link IntegrationRSocketEndpoint} beans and collect {@link RSocketRequester}s
+	 * from client connections.
+	 */
 	public ServerRSocketMessageHandler() {
 		this(false);
 	}
 
-	public ServerRSocketMessageHandler(boolean requestMappingCompatible) {
-		super(requestMappingCompatible);
-	}
-
-
-	public Map<Object, RSocketRequester> getClientRSocketRequesters() {
-		return Collections.unmodifiableMap(this.clientRSocketRequesters);
+	/**
+	 * Create an service side RSocket message handler instance for delegating
+	 * to {@link IntegrationRSocketEndpoint} beans and collect {@link RSocketRequester}s
+	 * from client connections.
+	 * When {@code messageMappingCompatible == true}, this class also handles
+	 * {@link org.springframework.messaging.handler.annotation.MessageMapping} methods
+	 * as it is done by the standard
+	 * {@link org.springframework.messaging.rsocket.annotation.support.RSocketMessageHandler}.
+	 * @param messageMappingCompatible whether handle also
+	 * {@link org.springframework.messaging.handler.annotation.MessageMapping}.
+	 */
+	public ServerRSocketMessageHandler(boolean messageMappingCompatible) {
+		super(messageMappingCompatible);
 	}
 
+	/**
+	 * Configure a {@link BiFunction} to extract a key for mapping connected {@link RSocketRequester}s.
+	 * Defaults to the {@code destination} a client is connected.
+	 * @param clientRSocketKeyStrategy the {@link BiFunction} to use.
+	 */
 	public void setClientRSocketKeyStrategy(
 			BiFunction<Map<String, Object>, DataBuffer, Object> clientRSocketKeyStrategy) {
 
@@ -77,6 +106,25 @@ public class ServerRSocketMessageHandler extends IntegrationRSocketMessageHandle
 		this.clientRSocketKeyStrategy = clientRSocketKeyStrategy;
 	}
 
+	/**
+	 * Get connected {@link RSocketRequester}s mapped by the keys from the connect messages.
+	 * @return the map of connected {@link RSocketRequester}s.
+	 * @see #setClientRSocketKeyStrategy
+	 */
+	public Map<Object, RSocketRequester> getClientRSocketRequesters() {
+		return Collections.unmodifiableMap(this.clientRSocketRequesters);
+	}
+
+	/**
+	 * Obtain a connected {@link RSocketRequester} mapped by provided key or null.
+	 * @param key the key for mapped {@link RSocketRequester} if any.
+	 * @return the mapped {@link RSocketRequester} or null.
+	 */
+	@Nullable
+	public RSocketRequester getClientRSocketRequester(Object key) {
+		return this.clientRSocketRequesters.get(key);
+	}
+
 	@Override
 	public void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher) {
 		this.applicationEventPublisher = applicationEventPublisher;

src/reference/asciidoc/rsocket.adoc

@@ -74,6 +74,11 @@ public void onApplicationEvent(RSocketConnectedEvent event) {
 All the options, including `RSocketStrategies` bean and `@EventListener` for `RSocketConnectedEvent`, are optional.
 See `ServerRSocketConnector` JavaDocs for more information.
 
+Starting with version 5.2.1, the `ServerRSocketMessageHandler` is extracted to a public, top-level class for possible connection with an existing RSocket server.
+When a `ServerRSocketConnector` is supplied with an external instance of `ServerRSocketMessageHandler`, it doesn't create an RSocket server internally and just delegates all the handling logic to the provided instance.
+In addition the `ServerRSocketMessageHandler` can be configured with a `messageMappingCompatible` flag to handle also `@MessageMapping` for an RSocket controller, fully replacing the functionality provided by the standard `RSocketMessageHandler`.
+This can be useful in mixed configurations, when classic `@MessageMapping` methods are present in the same application along with RSocket channel adapters and an externally configured RSocket server is present in the application.
+
 The `ClientRSocketConnector` serves as a holder for `RSocketRequester` based on the `RSocket` connected via the provided `ClientTransport`.
 The `RSocketFactory.ClientRSocketFactory` can be customized with the provided `ClientRSocketFactoryConfigurer`.
 The `setupRoute` (with optional templates variables) and `setupData` with metadata can be also configured on this component.