Introduce SubProtocolHandler abstraction

Add SubProtocolHandler to encapsulate the logic for using a
sub-protocol.

A SubProtocolWebSocketHandler is also provided to
delegate to the appropriate SubProtocolHandler based on the
negotiated sub-protocol value at handshake.

StompSubProtocolHandler provides handling for STOMP messages.

Issue: SPR-10786

spring-messaging/src/main/java/org/springframework/messaging/handler/websocket/SubProtocolHandler.java

+/*
+ * Copyright 2002-2013 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.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.messaging.handler.websocket;
+
+import java.util.List;
+
+import org.springframework.messaging.Message;
+import org.springframework.messaging.MessageChannel;
+import org.springframework.web.socket.CloseStatus;
+import org.springframework.web.socket.WebSocketMessage;
+import org.springframework.web.socket.WebSocketSession;
+
+
+/**
+ * A contract for handling WebSocket messages as part of a higher level protocol, referred
+ * to as "sub-protocol" in the WebSocket RFC specification. Handles both
+ * {@link WebSocketMessage}s from a client as well as {@link Message}s to a client.
+ * <p>
+ * Implementations of this interface can be configured on a
+ * {@link SubProtocolWebSocketHandler} which selects a sub-protocol handler to delegate
+ * messages to based on the sub-protocol requested by the client through the
+ * {@code Sec-WebSocket-Protocol} request header.
+ *
+ * @author Andy Wilkinson
+ * @author Rossen Stoyanchev
+ *
+ * @since 4.0
+ */
+public interface SubProtocolHandler {
+
+	/**
+	 * Return the list of sub-protocols supported by this handler, never {@code null}.
+	 */
+	List<String> getSupportedProtocols();
+
+	/**
+	 * Handle the given {@link WebSocketMessage} received from a client.
+	 *
+	 * @param session the client session
+	 * @param message the client message
+	 * @param outputChannel an output channel to send messages to
+	 */
+	void handleMessageFromClient(WebSocketSession session, WebSocketMessage message,
+			MessageChannel outputChannel) throws Exception;
+
+	/**
+	 * Handle the given {@link Message} to the client associated with the given WebSocket
+	 * session.
+	 *
+	 * @param session the client session
+	 * @param message the client message
+	 */
+	void handleMessageToClient(WebSocketSession session, Message<?> message) throws Exception;
+
+	/**
+	 * Resolve the session id from the given message or return {@code null}.
+	 *
+	 * @param the message to resolve the session id from
+	 */
+	String resolveSessionId(Message<?> message);
+
+	/**
+	 * Invoked after a {@link WebSocketSession} has started.
+	 *
+	 * @param session the client session
+	 * @param outputChannel a channel
+	 */
+	void afterSessionStarted(WebSocketSession session, MessageChannel outputChannel) throws Exception;
+
+	/**
+	 * Invoked after a {@link WebSocketSession} has ended.
+	 *
+	 * @param session the client session
+	 * @param closeStatus the reason why the session was closed
+	 * @param outputChannel a channel
+	 */
+	void afterSessionEnded(WebSocketSession session, CloseStatus closeStatus,
+			MessageChannel outputChannel) throws Exception;
+
+}

spring-messaging/src/main/java/org/springframework/messaging/handler/websocket/SubProtocolWebSocketHandler.java

+/*
+ * Copyright 2002-2013 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.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.messaging.handler.websocket;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+import java.util.concurrent.ConcurrentHashMap;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.springframework.messaging.Message;
+import org.springframework.messaging.MessageChannel;
+import org.springframework.messaging.MessageHandler;
+import org.springframework.messaging.MessagingException;
+import org.springframework.util.Assert;
+import org.springframework.util.CollectionUtils;
+import org.springframework.web.socket.CloseStatus;
+import org.springframework.web.socket.WebSocketHandler;
+import org.springframework.web.socket.WebSocketMessage;
+import org.springframework.web.socket.WebSocketSession;
+
+
+/**
+ * A {@link WebSocketHandler} that delegates messages to a {@link SubProtocolHandler}
+ * based on the sub-protocol value requested by the client through the
+ * {@code Sec-WebSocket-Protocol} request header A default handler can also be configured
+ * to use if the client does not request a specific sub-protocol.
+ *
+ * @author Rossen Stoyanchev
+ * @author Andy Wilkinson
+ *
+ * @since 4.0
+ */
+public class SubProtocolWebSocketHandler implements WebSocketHandler, MessageHandler {
+
+	private final Log logger = LogFactory.getLog(SubProtocolWebSocketHandler.class);
+
+	private final MessageChannel outputChannel;
+
+	private final Map<String, SubProtocolHandler> protocolHandlers =
+			new TreeMap<String, SubProtocolHandler>(String.CASE_INSENSITIVE_ORDER);
+
+	private SubProtocolHandler defaultProtocolHandler;
+
+	private final Map<String, WebSocketSession> sessions = new ConcurrentHashMap<String, WebSocketSession>();
+
+
+	/**
+	 * @param outputChannel
+	 */
+	public SubProtocolWebSocketHandler(MessageChannel outputChannel) {
+		Assert.notNull(outputChannel, "outputChannel is required");
+		this.outputChannel = outputChannel;
+	}
+
+	/**
+	 * Configure one or more handlers to use depending on the sub-protocol requested by
+	 * the client in the WebSocket handshake request.
+	 *
+	 * @param protocolHandlers the sub-protocol handlers to use
+	 */
+	public void setProtocolHandlers(List<SubProtocolHandler> protocolHandlers) {
+		this.protocolHandlers.clear();
+		for (SubProtocolHandler handler: protocolHandlers) {
+			List<String> protocols = handler.getSupportedProtocols();
+			if (CollectionUtils.isEmpty(protocols)) {
+				logger.warn("No sub-protocols, ignoring handler " + handler);
+				continue;
+			}
+			for (String protocol: protocols) {
+				SubProtocolHandler replaced = this.protocolHandlers.put(protocol, handler);
+				if (replaced != null) {
+					throw new IllegalStateException("Failed to map handler " + handler
+							+ " to protocol '" + protocol + "', it is already mapped to handler " + replaced);
+				}
+			}
+		}
+		if ((this.protocolHandlers.size() == 1) &&(this.defaultProtocolHandler == null)) {
+			this.defaultProtocolHandler = this.protocolHandlers.values().iterator().next();
+		}
+	}
+
+	/**
+	 * @return the configured sub-protocol handlers
+	 */
+	public Map<String, SubProtocolHandler> getProtocolHandlers() {
+		return this.protocolHandlers;
+	}
+
+	/**
+	 * Set the {@link SubProtocolHandler} to use when the client did not request a
+	 * sub-protocol.
+	 *
+	 * @param defaultProtocolHandler the default handler
+	 */
+	public void setDefaultProtocolHandler(SubProtocolHandler defaultProtocolHandler) {
+		this.defaultProtocolHandler = defaultProtocolHandler;
+		if (this.protocolHandlers.isEmpty()) {
+			setProtocolHandlers(Arrays.asList(defaultProtocolHandler));
+		}
+	}
+
+	/**
+	 * @return the default sub-protocol handler to use
+	 */
+	public SubProtocolHandler getDefaultProtocolHandler() {
+		return this.defaultProtocolHandler;
+	}
+
+
+	@Override
+	public void afterConnectionEstablished(WebSocketSession session) throws Exception {
+		this.sessions.put(session.getId(), session);
+		getProtocolHandler(session).afterSessionStarted(session, this.outputChannel);
+	}
+
+	protected final SubProtocolHandler getProtocolHandler(WebSocketSession session) {
+		SubProtocolHandler handler;
+		String protocol = session.getAcceptedProtocol();
+		if (protocol != null) {
+			handler = this.protocolHandlers.get(protocol);
+			Assert.state(handler != null,
+					"No handler for sub-protocol '" + protocol + "', handlers=" + this.protocolHandlers);
+		}
+		else {
+			handler = this.defaultProtocolHandler;
+			Assert.state(handler != null,
+					"No sub-protocol was requested and a default sub-protocol handler was not configured");
+		}
+		return handler;
+	}
+
+	@Override
+	public void handleMessage(WebSocketSession session, WebSocketMessage<?> message) throws Exception {
+		getProtocolHandler(session).handleMessageFromClient(session, message, this.outputChannel);
+	}
+
+	@Override
+	public void handleMessage(Message<?> message) throws MessagingException {
+
+		String sessionId = resolveSessionId(message);
+		if (sessionId == null) {
+			logger.error("sessionId not found in message " + message);
+			return;
+		}
+
+		WebSocketSession session = this.sessions.get(sessionId);
+		if (session == null) {
+			logger.error("Session not found for session with id " + sessionId);
+			return;
+		}
+
+		try {
+			getProtocolHandler(session).handleMessageToClient(session, message);
+		}
+		catch (Exception e) {
+			logger.error("Failed to send message to client " + message, e);
+		}
+	}
+
+	private String resolveSessionId(Message<?> message) {
+		for (SubProtocolHandler handler : this.protocolHandlers.values()) {
+			String sessionId = handler.resolveSessionId(message);
+			if (sessionId != null) {
+				return sessionId;
+			}
+		}
+		if (this.defaultProtocolHandler != null) {
+			String sessionId = this.defaultProtocolHandler.resolveSessionId(message);
+			if (sessionId != null) {
+				return sessionId;
+			}
+		}
+		return null;
+	}
+
+	@Override
+	public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
+	}
+
+	@Override
+	public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {
+		this.sessions.remove(session.getId());
+		getProtocolHandler(session).afterSessionEnded(session, closeStatus, this.outputChannel);
+	}
+
+	@Override
+	public boolean supportsPartialMessages() {
+		return false;
+	}
+
+}

spring-messaging/src/main/java/org/springframework/messaging/simp/package-info.java

 /**
- * Generic support for simple messaging protocols (like STOMP).
+ * Generic support for SImple Messaging Protocols such as STOMP.
  */
 package org.springframework.messaging.simp;

spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompBrokerRelayMessageHandler.java

@@ -197,7 +197,7 @@ public class StompBrokerRelayMessageHandler implements MessageHandler, SmartLife
 
 	/**
 	 * Open a "system" session for sending messages from parts of the application
-	 * not assoicated with a client STOMP session.
+	 * not associated with a client STOMP session.
 	 */
 	private void openSystemSession() {
 
@@ -449,12 +449,21 @@ public class StompBrokerRelayMessageHandler implements MessageHandler, SmartLife
 			}
 		}
 
-		private boolean forwardInternal(Message<?> message, TcpConnection<String, String> connection) {
+		private boolean forwardInternal(final Message<?> message, TcpConnection<String, String> connection) {
 			if (logger.isTraceEnabled()) {
 				logger.trace("Forwarding message to STOMP broker, message id=" + message.getHeaders().getId());
 			}
 			byte[] bytes = stompMessageConverter.fromMessage(message);
-			connection.send(new String(bytes, Charset.forName("UTF-8")));
+			connection.send(new String(bytes, Charset.forName("UTF-8")), new Consumer<Boolean>() {
+				@Override
+				public void accept(Boolean success) {
+					if (!success) {
+						String sessionId = StompHeaderAccessor.wrap(message).getSessionId();
+						relaySessions.remove(sessionId);
+						sendError(sessionId, "Failed to relay message to broker");
+					}
+				}
+			});
 
 			// TODO: detect if send fails and send ERROR downstream (except on DISCONNECT)
 			return true;

spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompWebSocketHandler.java → spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompProtocolHandler.java

@@ -5,7 +5,7 @@
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
- *      http://www.apache.org/licenses/LICENSE-2.0
+ * http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
@@ -13,36 +13,38 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.springframework.messaging.simp.stomp;
 
 import java.io.IOException;
 import java.nio.charset.Charset;
 import java.security.Principal;
-import java.util.Map;
+import java.util.Arrays;
+import java.util.List;
 import java.util.Set;
-import java.util.concurrent.ConcurrentHashMap;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.springframework.messaging.Message;
 import org.springframework.messaging.MessageChannel;
-import org.springframework.messaging.MessageHandler;
+import org.springframework.messaging.handler.websocket.SubProtocolHandler;
 import org.springframework.messaging.simp.SimpMessageType;
 import org.springframework.messaging.simp.handler.MutableUserQueueSuffixResolver;
 import org.springframework.messaging.support.MessageBuilder;
+import org.springframework.util.Assert;
 import org.springframework.web.socket.CloseStatus;
 import org.springframework.web.socket.TextMessage;
+import org.springframework.web.socket.WebSocketMessage;
 import org.springframework.web.socket.WebSocketSession;
-import org.springframework.web.socket.adapter.TextWebSocketHandlerAdapter;
-
-import reactor.util.Assert;
-
 
 /**
+ * A {@link SubProtocolHandler} for STOMP that supports versions 1.0, 1.1, and 1.2 of the
+ * STOMP specification.
+ *
  * @author Rossen Stoyanchev
- * @since 4.0
+ * @author Andy Wilkinson
  */
-public class StompWebSocketHandler extends TextWebSocketHandlerAdapter implements MessageHandler {
+public class StompProtocolHandler implements SubProtocolHandler {
 
 	/**
 	 * The name of the header set on the CONNECTED frame indicating the name of the user
@@ -58,25 +60,11 @@ public class StompWebSocketHandler extends TextWebSocketHandlerAdapter implement
 	 */
 	public static final String QUEUE_SUFFIX_HEADER = "queue-suffix";
 
-
-	private static Log logger = LogFactory.getLog(StompWebSocketHandler.class);
-
-	private MessageChannel dispatchChannel;
-
-	private MutableUserQueueSuffixResolver queueSuffixResolver;
+	private final Log logger = LogFactory.getLog(StompProtocolHandler.class);
 
 	private final StompMessageConverter stompMessageConverter = new StompMessageConverter();
 
-	private final Map<String, WebSocketSession> sessions = new ConcurrentHashMap<String, WebSocketSession>();
-
-
-	/**
-	 * @param dispatchChannel the channel to send client STOMP/WebSocket messages to
-	 */
-	public StompWebSocketHandler(MessageChannel dispatchChannel) {
-		Assert.notNull(dispatchChannel, "dispatchChannel is required");
-		this.dispatchChannel = dispatchChannel;
-	}
+	private MutableUserQueueSuffixResolver queueSuffixResolver;
 
 
 	/**
@@ -94,23 +82,20 @@ public class StompWebSocketHandler extends TextWebSocketHandlerAdapter implement
 		return this.queueSuffixResolver;
 	}
 
-	public StompMessageConverter getStompMessageConverter() {
-		return this.stompMessageConverter;
-	}
-
-
 	@Override
-	public void afterConnectionEstablished(WebSocketSession session) throws Exception {
-		this.sessions.put(session.getId(), session);
+	public List<String> getSupportedProtocols() {
+		return Arrays.asList("v10.stomp", "v11.stomp", "v12.stomp");
 	}
 
 	/**
 	 * Handle incoming WebSocket messages from clients.
 	 */
-	@Override
-	protected void handleTextMessage(WebSocketSession session, TextMessage textMessage) {
+	public void handleMessageFromClient(WebSocketSession session, WebSocketMessage webSocketMessage,
+			MessageChannel outputChannel) {
+
 		try {
-			String payload = textMessage.getPayload();
+			Assert.isInstanceOf(TextMessage.class,  webSocketMessage);
+			String payload = ((TextMessage)webSocketMessage).getPayload();
 			Message<?> message = this.stompMessageConverter.toMessage(payload);
 
 			// TODO: validate size limits
@@ -124,13 +109,14 @@ public class StompWebSocketHandler extends TextWebSocketHandlerAdapter implement
 				StompHeaderAccessor headers = StompHeaderAccessor.wrap(message);
 				headers.setSessionId(session.getId());
 				headers.setUser(session.getPrincipal());
+
 				message = MessageBuilder.withPayloadAndHeaders(message.getPayload(), headers).build();
 
 				if (SimpMessageType.CONNECT.equals(headers.getMessageType())) {
 					handleConnect(session, message);
 				}
 
-				this.dispatchChannel.send(message);
+				outputChannel.send(message);
 
 			}
 			catch (Throwable t) {
@@ -147,6 +133,51 @@ public class StompWebSocketHandler extends TextWebSocketHandlerAdapter implement
 		}
 	}
 
+	/**
+	 * Handle STOMP messages going back out to WebSocket clients.
+	 */
+	@Override
+	public void handleMessageToClient(WebSocketSession session, Message<?> message) {
+
+		StompHeaderAccessor headers = StompHeaderAccessor.wrap(message);
+		headers.setCommandIfNotSet(StompCommand.MESSAGE);
+
+		if (StompCommand.CONNECTED.equals(headers.getCommand())) {
+			// Ignore for now since we already sent it
+			return;
+		}
+
+		if (StompCommand.MESSAGE.equals(headers.getCommand()) && (headers.getSubscriptionId() == null)) {
+			// TODO: failed message delivery mechanism
+			logger.error("Ignoring message, no subscriptionId header: " + message);
+			return;
+		}
+
+		if (!(message.getPayload() instanceof byte[])) {
+			// TODO: failed message delivery mechanism
+			logger.error("Ignoring message, expected byte[] content: " + message);
+			return;
+		}
+
+		try {
+			message = MessageBuilder.withPayloadAndHeaders(message.getPayload(), headers).build();
+			byte[] bytes = this.stompMessageConverter.fromMessage(message);
+			session.sendMessage(new TextMessage(new String(bytes, Charset.forName("UTF-8"))));
+		}
+		catch (Throwable t) {
+			sendErrorMessage(session, t);
+		}
+		finally {
+			if (StompCommand.ERROR.equals(headers.getCommand())) {
+				try {
+					session.close(CloseStatus.PROTOCOL_ERROR);
+				}
+				catch (IOException e) {
+				}
+			}
+		}
+	}
+
 	protected void handleConnect(WebSocketSession session, Message<?> message) throws IOException {
 
 		StompHeaderAccessor connectHeaders = StompHeaderAccessor.wrap(message);
@@ -200,78 +231,26 @@ public class StompWebSocketHandler extends TextWebSocketHandlerAdapter implement
 	}
 
 	@Override
-	public void afterConnectionClosed(WebSocketSession session, CloseStatus status) throws Exception {
-
-		String sessionId = session.getId();
-		this.sessions.remove(sessionId);
-
-		if ((this.queueSuffixResolver != null) && (session.getPrincipal() != null)) {
-			this.queueSuffixResolver.removeQueueSuffix(session.getPrincipal().getName(), sessionId);
-		}
-
-		StompHeaderAccessor headers = StompHeaderAccessor.create(StompCommand.DISCONNECT);
-		headers.setSessionId(sessionId);
-		Message<?> message = MessageBuilder.withPayloadAndHeaders(new byte[0], headers).build();
-		this.dispatchChannel.send(message);
+	public String resolveSessionId(Message<?> message) {
+		StompHeaderAccessor headers = StompHeaderAccessor.wrap(message);
+		return headers.getSessionId();
 	}
 
-	/**
-	 * Handle STOMP messages going back out to WebSocket clients.
-	 */
 	@Override
-	public void handleMessage(Message<?> message) {
-
-		StompHeaderAccessor headers = StompHeaderAccessor.wrap(message);
-		headers.setCommandIfNotSet(StompCommand.MESSAGE);
-
-		if (StompCommand.CONNECTED.equals(headers.getCommand())) {
-			// Ignore for now since we already sent it
-			return;
-		}
-
-		String sessionId = headers.getSessionId();
-		if (sessionId == null) {
-			// TODO: failed message delivery mechanism
-			logger.error("Ignoring message, no sessionId header: " + message);
-			return;
-		}
-
-		WebSocketSession session = this.sessions.get(sessionId);
-		if (session == null) {
-			// TODO: failed message delivery mechanism
-			logger.error("Ignoring message, sessionId not found: " + message);
-			return;
-		}
+	public void afterSessionStarted(WebSocketSession session, MessageChannel outputChannel) {
+	}
 
-		if (StompCommand.MESSAGE.equals(headers.getCommand()) && (headers.getSubscriptionId() == null)) {
-			// TODO: failed message delivery mechanism
-			logger.error("Ignoring message, no subscriptionId header: " + message);
-			return;
-		}
+	@Override
+	public void afterSessionEnded(WebSocketSession session, CloseStatus closeStatus, MessageChannel outputChannel) {
 
-		if (!(message.getPayload() instanceof byte[])) {
-			// TODO: failed message delivery mechanism
-			logger.error("Ignoring message, expected byte[] content: " + message);
-			return;
+		if ((this.queueSuffixResolver != null) && (session.getPrincipal() != null)) {
+			this.queueSuffixResolver.removeQueueSuffix(session.getPrincipal().getName(), session.getId());
 		}
 
-		try {
-			message = MessageBuilder.withPayloadAndHeaders(message.getPayload(), headers).build();
-			byte[] bytes = this.stompMessageConverter.fromMessage(message);
-			session.sendMessage(new TextMessage(new String(bytes, Charset.forName("UTF-8"))));
-		}
-		catch (Throwable t) {
-			sendErrorMessage(session, t);
-		}
-		finally {
-			if (StompCommand.ERROR.equals(headers.getCommand())) {
-				try {
-					session.close(CloseStatus.PROTOCOL_ERROR);
-				}
-				catch (IOException e) {
-				}
-			}
-		}
+		StompHeaderAccessor headers = StompHeaderAccessor.create(StompCommand.DISCONNECT);
+		headers.setSessionId(session.getId());
+		Message<?> message = MessageBuilder.withPayloadAndHeaders(new byte[0], headers).build();
+		outputChannel.send(message);
 	}
 
 }

spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/package-info.java

+/**
+ * Generic support for simple messaging protocols (like STOMP).
+ */
+package org.springframework.messaging.simp.stomp;

spring-messaging/src/test/java/org/springframework/messaging/handler/websocket/SubProtocolWebSocketHandlerTests.java

+/*
+ * Copyright 2002-2013 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.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIOsNS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.messaging.handler.websocket;
+
+import java.util.Arrays;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.springframework.messaging.MessageChannel;
+import org.springframework.web.socket.support.TestWebSocketSession;
+
+import static org.mockito.Mockito.*;
+
+
+/**
+ * Test fixture for {@link SubProtocolWebSocketHandler}.
+ *
+ * @author Rossen Stoyanchev
+ * @author Andy Wilkinson
+ */
+public class SubProtocolWebSocketHandlerTests {
+
+	private SubProtocolWebSocketHandler webSocketHandler;
+
+	private TestWebSocketSession session;
+
+	@Mock
+	SubProtocolHandler stompHandler;
+
+	@Mock
+	SubProtocolHandler mqttHandler;
+
+	@Mock
+	SubProtocolHandler defaultHandler;
+
+	@Mock
+	MessageChannel channel;
+
+
+	@Before
+	public void setup() {
+		MockitoAnnotations.initMocks(this);
+
+		this.webSocketHandler = new SubProtocolWebSocketHandler(this.channel);
+		when(stompHandler.getSupportedProtocols()).thenReturn(Arrays.asList("STOMP"));
+		when(mqttHandler.getSupportedProtocols()).thenReturn(Arrays.asList("MQTT"));
+
+		this.session = new TestWebSocketSession();
+		this.session.setId("1");
+	}
+
+
+	@Test
+	public void subProtocolMatch() throws Exception {
+		this.webSocketHandler.setProtocolHandlers(Arrays.asList(stompHandler, mqttHandler));
+		this.session.setAcceptedProtocol("sToMp");
+		this.webSocketHandler.afterConnectionEstablished(session);
+
+		verify(this.stompHandler).afterSessionStarted(session, this.channel);
+		verify(this.mqttHandler, times(0)).afterSessionStarted(session, this.channel);
+	}
+
+	@Test
+	public void subProtocolDefaultHandlerOnly() throws Exception {
+		this.webSocketHandler.setDefaultProtocolHandler(stompHandler);
+		this.session.setAcceptedProtocol("sToMp");
+		this.webSocketHandler.afterConnectionEstablished(session);
+
+		verify(this.stompHandler).afterSessionStarted(session, this.channel);
+	}
+
+	@Test(expected=IllegalStateException.class)
+	public void subProtocolNoMatch() throws Exception {
+		this.webSocketHandler.setDefaultProtocolHandler(defaultHandler);
+		this.webSocketHandler.setProtocolHandlers(Arrays.asList(stompHandler, mqttHandler));
+		this.session.setAcceptedProtocol("wamp");
+
+		this.webSocketHandler.afterConnectionEstablished(session);
+	}
+
+	@Test
+	public void noSubProtocol() throws Exception {
+		this.webSocketHandler.setDefaultProtocolHandler(defaultHandler);
+		this.webSocketHandler.afterConnectionEstablished(session);
+
+		verify(this.defaultHandler).afterSessionStarted(session, this.channel);
+		verify(this.stompHandler, times(0)).afterSessionStarted(session, this.channel);
+		verify(this.mqttHandler, times(0)).afterSessionStarted(session, this.channel);
+	}
+
+	@Test
+	public void noSubProtocolOneHandler() throws Exception {
+		this.webSocketHandler.setProtocolHandlers(Arrays.asList(stompHandler));
+		this.webSocketHandler.afterConnectionEstablished(session);
+
+		verify(this.stompHandler).afterSessionStarted(session, this.channel);
+	}
+
+	@Test(expected=IllegalStateException.class)
+	public void noSubProtocolTwoHandlers() throws Exception {
+		this.webSocketHandler.setProtocolHandlers(Arrays.asList(stompHandler, mqttHandler));
+		this.webSocketHandler.afterConnectionEstablished(session);
+	}
+
+	@Test(expected=IllegalStateException.class)
+	public void noSubProtocolNoDefaultHandler() throws Exception {
+		this.webSocketHandler.setProtocolHandlers(Arrays.asList(stompHandler, mqttHandler));
+		this.webSocketHandler.afterConnectionEstablished(session);
+	}
+
+}

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

@@ -20,12 +20,12 @@ package org.springframework.web.socket;
  * A handler for WebSocket messages and lifecycle events.
  *
  * <p>Implementations of this interface are encouraged to handle exceptions locally where
- * it makes sense or alternatively let the exception bubble up in which case the exception
- * is logged and the session closed with
- * {@link CloseStatus#SERVER_ERROR SERVER_ERROR(1011)} by default. The exception handling
+ * it makes sense or alternatively let the exception bubble up in which case by default
+ * the exception is logged and the session closed with
+ * {@link CloseStatus#SERVER_ERROR SERVER_ERROR(1011)}. The exception handling
  * strategy is provided by
  * {@link org.springframework.web.socket.support.ExceptionWebSocketHandlerDecorator
- * ExceptionWebSocketHandlerDecorator}, which can be customized or replaced by decorating
+ * ExceptionWebSocketHandlerDecorator} and it can be customized or replaced by decorating
  * the {@link WebSocketHandler} with a different decorator.
  *
  * @author Rossen Stoyanchev
@@ -61,6 +61,7 @@ public interface WebSocketHandler {
 	 * transport error has occurred. Although the session may technically still be open,
 	 * depending on the underlying implementation, sending messages at this point is
 	 * discouraged and most likely will not succeed.
+	 *
 	 * @throws Exception this method can handle or propagate exceptions; see class-level
 	 *         Javadoc for details.
 	 */

spring-websocket/src/main/java/org/springframework/web/socket/support/MultiProtocolWebSocketHandler.java

-/*
- * Copyright 2002-2013 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.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.springframework.web.socket.support;
-
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.Map;
-
-import org.springframework.util.Assert;
-import org.springframework.web.socket.CloseStatus;
-import org.springframework.web.socket.WebSocketHandler;
-import org.springframework.web.socket.WebSocketMessage;
-import org.springframework.web.socket.WebSocketSession;
-
-
-/**
- * A {@link WebSocketHandler} that delegates to other {@link WebSocketHandler} instances
- * based on the sub-protocol value accepted at the handshake. A default handler can also
- * be configured for use by default when a sub-protocol value if the WebSocket session
- * does not have a sub-protocol value associated with it.
- *
- * @author Rossen Stoyanchev
- * @since 4.0
- */
-public class MultiProtocolWebSocketHandler implements WebSocketHandler {
-
-	private WebSocketHandler defaultHandler;
-
-	private Map<String, WebSocketHandler> handlers = new HashMap<String, WebSocketHandler>();
-
-
-	/**
-	 * Configure {@link WebSocketHandler}'s to use by sub-protocol. The values for
-	 * sub-protocols are case insensitive.
-	 */
-	public void setProtocolHandlers(Map<String, WebSocketHandler> protocolHandlers) {
-		this.handlers.clear();
-		for (String protocol : protocolHandlers.keySet()) {
-			this.handlers.put(protocol.toLowerCase(), protocolHandlers.get(protocol));
-		}
-	}
-
-	/**
-	 * Return a read-only copy of the sub-protocol handler map.
-	 */
-	public Map<String, WebSocketHandler> getProtocolHandlers() {
-		return Collections.unmodifiableMap(this.handlers);
-	}
-
-	/**
-	 * Set the default {@link WebSocketHandler} to use if a sub-protocol was not
-	 * requested.
-	 */
-	public void setDefaultProtocolHandler(WebSocketHandler defaultHandler) {
-		this.defaultHandler = defaultHandler;
-	}
-
-	/**
-	 * Return the default {@link WebSocketHandler} to be used.
-	 */
-	public WebSocketHandler getDefaultProtocolHandler() {
-		return this.defaultHandler;
-	}
-
-
-	@Override
-	public void afterConnectionEstablished(WebSocketSession session) throws Exception {
-		WebSocketHandler handler = getHandlerForSession(session);
-		handler.afterConnectionEstablished(session);
-	}
-
-	private WebSocketHandler getHandlerForSession(WebSocketSession session) {
-		WebSocketHandler handler = null;
-		String protocol = session.getAcceptedProtocol();
-		if (protocol != null) {
-			handler = this.handlers.get(protocol.toLowerCase());
-			Assert.state(handler != null,
-					"No WebSocketHandler for sub-protocol '" + protocol + "', handlers=" + this.handlers);
-		}
-		else {
-			handler = this.defaultHandler;
-			Assert.state(handler != null,
-					"No sub-protocol was requested and no default WebSocketHandler was configured");
-		}
-		return handler;
-	}
-
-	@Override
-	public void handleMessage(WebSocketSession session, WebSocketMessage<?> message) throws Exception {
-		WebSocketHandler handler = getHandlerForSession(session);
-		handler.handleMessage(session, message);
-	}
-
-	@Override
-	public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
-		WebSocketHandler handler = getHandlerForSession(session);
-		handler.handleTransportError(session, exception);
-	}
-
-	@Override
-	public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {
-		WebSocketHandler handler = getHandlerForSession(session);
-		handler.afterConnectionClosed(session, closeStatus);
-	}
-
-	@Override
-	public boolean supportsPartialMessages() {
-		return false;
-	}
-
-}

spring-websocket/src/test/java/org/springframework/web/socket/support/MultiProtocolWebSocketHandlerTests.java

-/*
- * Copyright 2002-2013 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.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIOsNS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.springframework.web.socket.support;
-
-import java.util.HashMap;
-import java.util.Map;
-
-import org.junit.Before;
-import org.junit.Test;
-import org.mockito.Mock;
-import org.mockito.MockitoAnnotations;
-import org.springframework.web.socket.WebSocketHandler;
-
-import static org.mockito.Mockito.*;
-
-
-/**
- * Test fixture for {@link MultiProtocolWebSocketHandler}.
- *
- * @author Rossen Stoyanchev
- */
-public class MultiProtocolWebSocketHandlerTests {
-
-	private MultiProtocolWebSocketHandler multiProtocolHandler;
-
-	@Mock
-	WebSocketHandler stompHandler;
-
-	@Mock
-	WebSocketHandler mqttHandler;
-
-	@Mock
-	WebSocketHandler defaultHandler;
-
-
-	@Before
-	public void setup() {
-
-		MockitoAnnotations.initMocks(this);
-
-		Map<String, WebSocketHandler> handlers = new HashMap<String, WebSocketHandler>();
-		handlers.put("STOMP", this.stompHandler);
-		handlers.put("MQTT", this.mqttHandler);
-
-		this.multiProtocolHandler = new MultiProtocolWebSocketHandler();
-		this.multiProtocolHandler.setProtocolHandlers(handlers);
-		this.multiProtocolHandler.setDefaultProtocolHandler(this.defaultHandler);
-	}
-
-
-	@Test
-	public void subProtocol() throws Exception {
-
-		TestWebSocketSession session = new TestWebSocketSession();
-		session.setAcceptedProtocol("sToMp");
-
-		this.multiProtocolHandler.afterConnectionEstablished(session);
-
-		verify(this.stompHandler).afterConnectionEstablished(session);
-		verifyZeroInteractions(this.mqttHandler);
-	}
-
-	@Test(expected=IllegalStateException.class)
-	public void subProtocolNoMatch() throws Exception {
-
-		TestWebSocketSession session = new TestWebSocketSession();
-		session.setAcceptedProtocol("wamp");
-
-		this.multiProtocolHandler.afterConnectionEstablished(session);
-	}
-
-	@Test
-	public void noSubProtocol() throws Exception {
-
-		TestWebSocketSession session = new TestWebSocketSession();
-
-		this.multiProtocolHandler.afterConnectionEstablished(session);
-
-		verify(this.defaultHandler).afterConnectionEstablished(session);
-		verifyZeroInteractions(this.stompHandler, this.mqttHandler);
-	}
-
-	@Test(expected=IllegalStateException.class)
-	public void noSubProtocolNoDefaultHandler() throws Exception {
-
-		TestWebSocketSession session = new TestWebSocketSession();
-
-		this.multiProtocolHandler.setDefaultProtocolHandler(null);
-		this.multiProtocolHandler.afterConnectionEstablished(session);
-	}
-
-}