/**
 * Determine the sub-protocols supported by the given WebSocketHandler by
 * checking whether it is an instance of {@link SubProtocolCapable}.
 * @param handler the handler to check
 * @return a list of supported protocols, or an empty list if none available
 */
protected final List<String> determineHandlerSupportedProtocols(WebSocketHandler handler) {
	WebSocketHandler handlerToCheck = WebSocketHandlerDecorator.unwrap(handler);
	List<String> subProtocols = null;
	if (handlerToCheck instanceof SubProtocolCapable) {
		subProtocols = ((SubProtocolCapable) handlerToCheck).getSubProtocols();
	}
	return (subProtocols != null ? subProtocols : Collections.emptyList());
}
 

public SockJsWebSocketHandler(SockJsServiceConfig serviceConfig, WebSocketHandler webSocketHandler,
		WebSocketServerSockJsSession sockJsSession) {

	Assert.notNull(serviceConfig, "serviceConfig must not be null");
	Assert.notNull(webSocketHandler, "webSocketHandler must not be null");
	Assert.notNull(sockJsSession, "session must not be null");

	this.sockJsServiceConfig = serviceConfig;
	this.sockJsSession = sockJsSession;

	webSocketHandler = WebSocketHandlerDecorator.unwrap(webSocketHandler);
	this.subProtocols = ((webSocketHandler instanceof SubProtocolCapable) ?
			new ArrayList<>(((SubProtocolCapable) webSocketHandler).getSubProtocols()) : Collections.emptyList());
}
 

/**
 * Determine the sub-protocols supported by the given WebSocketHandler by
 * checking whether it is an instance of {@link SubProtocolCapable}.
 * @param handler the handler to check
 * @return a list of supported protocols, or an empty list if none available
 */
protected final List<String> determineHandlerSupportedProtocols(WebSocketHandler handler) {
	WebSocketHandler handlerToCheck = WebSocketHandlerDecorator.unwrap(handler);
	List<String> subProtocols = null;
	if (handlerToCheck instanceof SubProtocolCapable) {
		subProtocols = ((SubProtocolCapable) handlerToCheck).getSubProtocols();
	}
	return (subProtocols != null ? subProtocols : Collections.emptyList());
}
 

public SockJsWebSocketHandler(SockJsServiceConfig serviceConfig, WebSocketHandler webSocketHandler,
		WebSocketServerSockJsSession sockJsSession) {

	Assert.notNull(serviceConfig, "serviceConfig must not be null");
	Assert.notNull(webSocketHandler, "webSocketHandler must not be null");
	Assert.notNull(sockJsSession, "session must not be null");

	this.sockJsServiceConfig = serviceConfig;
	this.sockJsSession = sockJsSession;

	webSocketHandler = WebSocketHandlerDecorator.unwrap(webSocketHandler);
	this.subProtocols = ((webSocketHandler instanceof SubProtocolCapable) ?
			new ArrayList<>(((SubProtocolCapable) webSocketHandler).getSubProtocols()) : Collections.emptyList());
}
 

/**
 * Determine the sub-protocols supported by the given WebSocketHandler by
 * checking whether it is an instance of {@link SubProtocolCapable}.
 * @param handler the handler to check
 * @return a list of supported protocols, or an empty list if none available
 */
protected final List<String> determineHandlerSupportedProtocols(WebSocketHandler handler) {
	WebSocketHandler handlerToCheck = WebSocketHandlerDecorator.unwrap(handler);
	List<String> subProtocols = null;
	if (handlerToCheck instanceof SubProtocolCapable) {
		subProtocols = ((SubProtocolCapable) handlerToCheck).getSubProtocols();
	}
	return (subProtocols != null ? subProtocols : Collections.<String>emptyList());
}
 

public SockJsWebSocketHandler(SockJsServiceConfig serviceConfig, WebSocketHandler webSocketHandler,
		WebSocketServerSockJsSession sockJsSession) {

	Assert.notNull(serviceConfig, "serviceConfig must not be null");
	Assert.notNull(webSocketHandler, "webSocketHandler must not be null");
	Assert.notNull(sockJsSession, "session must not be null");

	this.sockJsServiceConfig = serviceConfig;
	this.sockJsSession = sockJsSession;

	webSocketHandler = WebSocketHandlerDecorator.unwrap(webSocketHandler);
	this.subProtocols = ((webSocketHandler instanceof SubProtocolCapable) ?
			new ArrayList<String>(((SubProtocolCapable) webSocketHandler).getSubProtocols()) : null);
}