After this change, annotated message handling methods configured to use
a destination prefix (e.g. "/app") no longer have to include the prefix
in their mapping. For example if a client sends a message to "/app/foo"
the annotated methods should be mapped with @MessageMapping("/foo").

Ensure configuration provided for WebSocketHandler's (eg interceptors,
or HandshakeHandler) are passed on to the SockJsService if congiured.

Better separate Servlet-specific parts of the configuration to make it
more obvious where non-Servlet alternatives could fit in.

Add more tests.

Improve WebSocket integration tests.

Issue: SPR-10880

Issue: SPR-10876

Issue: SRP-10868

Issue: SPR-10605

Issue: SPR-10835

Issue: SPR-10835

Issue: SPR-10861

Issue: SPR-10844

First try the endpoint type name converted to property
Then try @Component value

Issue: SPR-10605

While RC2 is not yet out, we need to support RC1 as well.
This change introduces temporary code that can be removed
once RC2 becomes available to avoid having to use Tomcat
snapshots.

This targets currently nightly snapshots and future release
of Glassfish 4.0.1.

After this change the DefaultHandshakeHandler delegates to a
server-specific RequestUpgradeStrategy to update the HTTP response for
the handshake request and to begin the WebSocket interaction.

The DefaultHandshakeHandler however still retains the initial
validation of the WebSocket handshake including negotation of origin,
sub-protocol, etc. This allows sub-classes to override various
aspects of the negotiation independant of the WebSocket engine.

In addition to implementing ServerEndpointConfig, the
ServerEndpointRegistration now also extends
ServerEndpointConfig.Configurator making it easier to override
handshake customization methods without having to extend a separate
class.

Tomcat now provides a method for initiating a WebSocket upgrade at
runtime vs relying on JSR-356 deployment at startup. This change
switches to use that latest feature. For more information on the
Tomcat change see:

https://issues.apache.org/bugzilla/show_bug.cgi?id=55314#c7

Although ServletHttpRequest provides access to Cookies, other
implementations may not. At the moment this was only needed
for SockJS to check the value of the JSESSIONID cookie. This
is now down by parsing the raw cookie values locally.

If comprehensive cookie support is to be added, we should
probably consider HttpHeaders as a potential candidate.

A HandshakeInterceptor can be used to intercept WebSocket handshakes
(or SockJS requests where a new session is created) in order to
inspect the request and response before and after the handshake
including the ability to pass attributes to the WebSocketHandler,
which the hander can access through
WebSocketSession.getHandshakeAttributes()

An HttpSessionHandshakeInterceptor is available that can copy
attributes from the HTTP session to make them available to the
WebSocket session.

Issue: SPR-10624

Update methods available on WebSocketSession interface.
Introduce DelegatingWebSocketSession interface.

Issue: SPR-10796

Add a factory method in ServerHttpRequest for creating a
ServerHttpAsyncRequestControl.

See javadoc in SockJsService for details.

Also remove ReadOnlyMultiValueMap, CollectionUtils has a method for
that already.

The method returning query parameters now returns only query string
parameters as opposed to any Servlet request parameter.

This commit also adds a ReadOnlyMultiValueMap.

ServerHttpAsyncResponseControl wraps a ServetHttpRequest and -Response
pair and allows putting the processing of the request in async mode
so that the response remains open until explicitly closed, either from
the current or from another thread.

ServletServerHttpAsyncResponseControl provides a Serlvet-based
implementation.

A getCookies method is now available on ServerHttpRequest with one
ServletServerCookie implementation that wraps a Servlet cookie.

The SockJS service makes use of this to check for an existing session
cookie in the request.

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

Issue: SPR-10800

After this change the top-level sockjs package contains the main types
for use in applications.

A SockJS message frame is an array of JSON-encoded messages and before
this change the use of the Jackson 2 library was hard-coded.

A Jackson 2 and Jackson 1.x implementations are provided and
automatically used if those libraries are present on the classpath.

Issue: SPR-10800

It makes it possible to deploy multiple WebSocketHandler's to a URL,
each supporting a different sub-protocol.

Issue: SPR-10786

The method WsServerContainer.getServerContainer() was removed from
JSR-356 but remained in Tomcat a little while longer. Instead the
ServerContainer is obtained through a ServletContext attribute.
Tomcat has now removed this method, hence the need for this fix.

Issue: SPR-10621

Issue: SPR-10721