SubProtocolWebSocketHandler provides protected decorateSession method

Issue: SPR-16089

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

@@ -126,7 +126,7 @@ public void sendMessage(WebSocketMessage<?> message) throws IOException {
 				if (logger.isTraceEnabled()) {
 					String text = String.format("Another send already in progress: " +
 							"session id '%s':, \"in-progress\" send time %d (ms), buffer size %d bytes",
-							getId(), getTimeSinceSendStarted(), this.bufferSize.get());
+							getId(), getTimeSinceSendStarted(), getBufferSize());
 					logger.trace(text);
 				}
 				checkSessionLimits();
@@ -166,14 +166,14 @@ private boolean tryFlushMessageBuffer() throws IOException {
 	private void checkSessionLimits() {
 		if (!shouldNotSend() && this.closeLock.tryLock()) {
 			try {
-				if (getTimeSinceSendStarted() > this.sendTimeLimit) {
+				if (getTimeSinceSendStarted() > getSendTimeLimit()) {
 					String format = "Message send time %d (ms) for session '%s' exceeded the allowed limit %d";
-					String reason = String.format(format, getTimeSinceSendStarted(), getId(), this.sendTimeLimit);
+					String reason = String.format(format, getTimeSinceSendStarted(), getId(), getSendTimeLimit());
 					limitExceeded(reason);
 				}
-				else if (this.bufferSize.get() > this.bufferSizeLimit) {
+				else if (getBufferSize() > getBufferSizeLimit()) {
 					String format = "The send buffer size %d bytes for session '%s' exceeded the allowed limit %d";
-					String reason = String.format(format, this.bufferSize.get(), getId(), this.bufferSizeLimit);
+					String reason = String.format(format, getBufferSize(), getId(), getBufferSizeLimit());
 					limitExceeded(reason);
 				}
 			}

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -26,24 +26,23 @@
 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
+ * 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.
+ *
+ * <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}.
+	 * Return the list of sub-protocols supported by this handler (never {@code null}).
 	 */
 	List<String> getSupportedProtocols();
 
@@ -53,12 +52,11 @@ public interface SubProtocolHandler {
 	 * @param message the client message
 	 * @param outputChannel an output channel to send messages to
 	 */
-	void handleMessageFromClient(WebSocketSession session, WebSocketMessage<?> message,
-			MessageChannel outputChannel) throws Exception;
+	void handleMessageFromClient(WebSocketSession session, WebSocketMessage<?> message, MessageChannel outputChannel)
+			throws Exception;
 
 	/**
-	 * Handle the given {@link Message} to the client associated with the given WebSocket
-	 * session.
+	 * Handle the given {@link Message} to the client associated with the given WebSocket session.
 	 * @param session the client session
 	 * @param message the client message
 	 */
@@ -84,7 +82,7 @@ void handleMessageFromClient(WebSocketSession session, WebSocketMessage<?> messa
 	 * @param closeStatus the reason why the session was closed
 	 * @param outputChannel a channel
 	 */
-	void afterSessionEnded(WebSocketSession session, CloseStatus closeStatus,
-			MessageChannel outputChannel) throws Exception;
+	void afterSessionEnded(WebSocketSession session, CloseStatus closeStatus, MessageChannel outputChannel)
+			throws Exception;
 
 }

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

@@ -16,7 +16,6 @@
 
 package org.springframework.web.socket.messaging;
 
-import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.LinkedHashSet;
@@ -292,7 +291,7 @@ public void afterConnectionEstablished(WebSocketSession session) throws Exceptio
 			return;
 		}
 		this.stats.incrementSessionCount(session);
-		session = new ConcurrentWebSocketSessionDecorator(session, getSendTimeLimit(), getSendBufferSizeLimit());
+		session = decorateSession(session);
 		this.sessions.put(session.getId(), new WebSocketSessionHolder(session));
 		findProtocolHandler(session).afterSessionStarted(session, this.clientInboundChannel);
 	}
@@ -377,6 +376,23 @@ public boolean supportsPartialMessages() {
 	}
 
 
+	/**
+	 * Decorate the given {@link WebSocketSession}, if desired.
+	 * <p>The default implementation builds a {@link ConcurrentWebSocketSessionDecorator}
+	 * with the configured {@link #getSendTimeLimit() send-time limit} and
+	 * {@link #getSendBufferSizeLimit() buffer-size limit}.
+	 * @param session the original {@code WebSocketSession}
+	 * @return the decorated {@code WebSocketSession}, or potentially the given session as-is
+	 * @since 4.3.13
+	 */
+	protected WebSocketSession decorateSession(WebSocketSession session) {
+		return new ConcurrentWebSocketSessionDecorator(session, getSendTimeLimit(), getSendBufferSizeLimit());
+	}
+
+	/**
+	 * Find a {@link SubProtocolHandler} for the given session.
+	 * @param session the {@code WebSocketSession} to find a handler for
+	 */
 	protected final SubProtocolHandler findProtocolHandler(WebSocketSession session) {
 		String protocol = null;
 		try {
@@ -432,12 +448,11 @@ private String resolveSessionId(Message<?> message) {
 	 * When a session is connected through a higher-level protocol it has a chance
 	 * to use heartbeat management to shut down sessions that are too slow to send
 	 * or receive messages. However, after a WebSocketSession is established and
-	 * before the higher level protocol is fully connected there is a possibility
-	 * for sessions to hang. This method checks and closes any sessions that have
-	 * been connected for more than 60 seconds without having received a single
-	 * message.
+	 * before the higher level protocol is fully connected there is a possibility for
+	 * sessions to hang. This method checks and closes any sessions that have been
+	 * connected for more than 60 seconds without having received a single message.
 	 */
-	private void checkSessions() throws IOException {
+	private void checkSessions() {
 		long currentTime = System.currentTimeMillis();
 		if (!isRunning() || (currentTime - this.lastSessionCheckTime < TIME_TO_FIRST_MESSAGE)) {
 			return;
@@ -497,12 +512,13 @@ private static class WebSocketSessionHolder {
 
 		private final WebSocketSession session;
 
-		private final long createTime = System.currentTimeMillis();
+		private final long createTime;
 
-		private volatile boolean handledMessages;
+		private volatile boolean hasHandledMessages;
 
-		private WebSocketSessionHolder(WebSocketSession session) {
+		public WebSocketSessionHolder(WebSocketSession session) {
 			this.session = session;
+			this.createTime = System.currentTimeMillis();
 		}
 
 		public WebSocketSession getSession() {
@@ -514,17 +530,17 @@ public long getCreateTime() {
 		}
 
 		public void setHasHandledMessages() {
-			this.handledMessages = true;
+			this.hasHandledMessages = true;
 		}
 
 		public boolean hasHandledMessages() {
-			return this.handledMessages;
+			return this.hasHandledMessages;
 		}
 
 		@Override
 		public String toString() {
 			return "WebSocketSessionHolder[session=" + this.session + ", createTime=" +
-					this.createTime + ", hasHandledMessages=" + this.handledMessages + "]";
+					this.createTime + ", hasHandledMessages=" + this.hasHandledMessages + "]";
 		}
 	}