Package com.vaadin.flow.server.communication

Class JSR356WebsocketInitializer

java.lang.Object

com.vaadin.flow.server.communication.JSR356WebsocketInitializer

All Implemented Interfaces:

EventListener, javax.servlet.ServletContextListener

public class JSR356WebsocketInitializer
extends Object
implements javax.servlet.ServletContextListener

Initializer class for JSR 356 websockets.

Websocket specification says that initialization of websocket end points should be done in the servlet context initialization phase. Some servers implement this strictly so that end points cannot be registered after the context initialization phase.

Note that WebListener is Servlet 3.0 API so this will not be run for older servers (unless added to web.xml), but these servers do not support JSR 356 websockets either.

For internal use only. May be renamed or removed in a future release.

Since:

1.0

Author:

Vaadin Ltd

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	JSR356WebsocketInitializer.FakeServletConfig	"ServletConfig" which only provides information from a ServletRegistration and its ServletContext.

Constructor Summary

Constructors

Constructor	Description
JSR356WebsocketInitializer()

Method Summary

Modifier and Type	Method	Description
void	contextDestroyed(javax.servlet.ServletContextEvent sce)
void	contextInitialized(javax.servlet.ServletContextEvent sce)
static String	getAttributeName(String servletName)	Returns the name of the attribute in the servlet context where the pre-initialized Atmosphere object is stored.
void	init(javax.servlet.ServletContext servletContext)	Initializes Atmosphere for use with Vaadin servlets found in the given context.
static void	initAtmosphereForVaadinServlet(javax.servlet.ServletRegistration servletRegistration, javax.servlet.ServletContext servletContext)	Initializes Atmosphere for use with the given Vaadin servlet
static boolean	isAtmosphereAvailable()	Checks if Atmosphere is available on the classpath.
protected boolean	isVaadinServlet(javax.servlet.ServletRegistration servletRegistration, javax.servlet.ServletContext servletContext)	Tries to determine if the given servlet registration refers to a Vaadin servlet.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

JSR356WebsocketInitializer

public JSR356WebsocketInitializer()

Method Detail

contextInitialized

public void contextInitialized(javax.servlet.ServletContextEvent sce)

Specified by:

contextInitialized in interface javax.servlet.ServletContextListener

init

public void init(javax.servlet.ServletContext servletContext)

Initializes Atmosphere for use with Vaadin servlets found in the given context.

For JSR 356 websockets to work properly, the initialization must be done in the servlet context initialization phase.

Parameters:

servletContext - The servlet context

initAtmosphereForVaadinServlet

public static void initAtmosphereForVaadinServlet(javax.servlet.ServletRegistration servletRegistration,
                                                  javax.servlet.ServletContext servletContext)

Initializes Atmosphere for use with the given Vaadin servlet

For JSR 356 websockets to work properly, the initialization must be done in the servlet context initialization phase.

Parameters:

servletRegistration - The servlet registration info for the servlet

servletContext - The servlet context

getAttributeName

public static String getAttributeName(String servletName)

Returns the name of the attribute in the servlet context where the pre-initialized Atmosphere object is stored.

Parameters:

servletName - The name of the servlet

Returns:

The attribute name which contains the initialized Atmosphere object

isVaadinServlet

protected boolean isVaadinServlet(javax.servlet.ServletRegistration servletRegistration,
                                  javax.servlet.ServletContext servletContext)

Tries to determine if the given servlet registration refers to a Vaadin servlet.

Parameters:

servletRegistration - The servlet registration info for the servlet

servletContext - the context of the servlet

Returns:

false if the servlet is definitely not a Vaadin servlet, true otherwise

contextDestroyed

public void contextDestroyed(javax.servlet.ServletContextEvent sce)

Specified by:

contextDestroyed in interface javax.servlet.ServletContextListener

isAtmosphereAvailable

public static boolean isAtmosphereAvailable()

Checks if Atmosphere is available on the classpath.

Returns:

true if Atmosphere is available, false otherwise