com.vaadin.server.communication.JSR356WebsocketInitializer Maven / Gradle / Ivy
/*
* Copyright 2000-2014 Vaadin Ltd.
*
* 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 com.vaadin.server.communication;
import java.util.Collections;
import java.util.Enumeration;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.ServletRegistration;
import javax.servlet.annotation.WebListener;
import org.atmosphere.cpr.AtmosphereFramework;
import com.vaadin.server.VaadinServlet;
/**
* 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 {@link 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.
*
* @since 7.5.0
* @author Vaadin Ltd
*/
@WebListener
public class JSR356WebsocketInitializer implements ServletContextListener {
private static boolean atmosphereAvailable = false;
static {
try {
org.atmosphere.util.Version.getRawVersion();
atmosphereAvailable = true;
} catch (NoClassDefFoundError e) {
}
}
/**
* "ServletConfig" which only provides information from a
* {@link ServletRegistration} and its {@link ServletContext}
*/
public static class FakeServletConfig implements ServletConfig {
private ServletRegistration servletRegistration;
private ServletContext servletContext;
public FakeServletConfig(ServletRegistration servletRegistration,
ServletContext servletContext) {
this.servletContext = servletContext;
this.servletRegistration = servletRegistration;
}
@Override
public String getServletName() {
return servletRegistration.getName();
}
@Override
public ServletContext getServletContext() {
return servletContext;
}
@Override
public String getInitParameter(String name) {
return servletRegistration.getInitParameter(name);
}
@Override
public Enumeration getInitParameterNames() {
return Collections.enumeration(servletRegistration
.getInitParameters().keySet());
}
}
@Override
public void contextInitialized(ServletContextEvent sce) {
ServletContext servletContext = sce.getServletContext();
if (servletContext.getMajorVersion() < 3) {
return;
}
if (!atmosphereAvailable) {
return;
}
Map regs = servletContext
.getServletRegistrations();
for (String servletName : regs.keySet()) {
ServletRegistration servletRegistration = regs.get(servletName);
if (isVaadinServlet(servletRegistration)) {
try {
initAtmosphereForVaadinServlet(servletRegistration,
servletContext);
} catch (Exception e) {
getLogger().log(
Level.WARNING,
"Failed to initialize Atmosphere for "
+ servletName, e);
}
}
}
}
/**
* 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.
*
* @param servletRegistration
* The servlet registration info for the servlet
* @param servletContext
*/
public static void initAtmosphereForVaadinServlet(
ServletRegistration servletRegistration,
ServletContext servletContext) {
String servletName = servletRegistration.getName();
String attributeName = getAttributeName(servletName);
if (servletContext.getAttribute(attributeName) != null) {
// Already initialized
getLogger().warning("Atmosphere already initialized");
return;
}
getLogger().finer("Creating AtmosphereFramework for " + servletName);
AtmosphereFramework framework = PushRequestHandler
.initAtmosphere(new FakeServletConfig(servletRegistration,
servletContext));
servletContext.setAttribute(attributeName, framework);
getLogger().finer("Created AtmosphereFramework for " + servletName);
}
/**
* Returns the name of the attribute in the servlet context where the
* pre-initialized Atmosphere object is stored
*
* @param servletName
* The name of the servlet
* @return The attribute name which contains the initialized Atmosphere
* object
*/
public static String getAttributeName(String servletName) {
return JSR356WebsocketInitializer.class.getName() + "." + servletName;
}
/**
* Tries to determine if the given servlet registration refers to a Vaadin
* servlet.
*
* @param servletRegistration
* The servlet registration info for the servlet
* @return false if the servlet is definitely not a Vaadin servlet, true
* otherwise
*/
protected boolean isVaadinServlet(ServletRegistration servletRegistration) {
try {
String servletClassName = servletRegistration.getClassName();
if (servletClassName.equals("com.ibm.ws.wsoc.WsocServlet")) {
// Websphere servlet which implements websocket endpoints,
// dynamically added
return false;
}
Class servletClass = Class.forName(servletClassName);
return VaadinServlet.class.isAssignableFrom(servletClass);
} catch (Exception e) {
// This will fail in OSGi environments, assume everything is a
// VaadinServlet
return true;
}
}
private static final Logger getLogger() {
return Logger.getLogger(JSR356WebsocketInitializer.class.getName());
}
@Override
public void contextDestroyed(ServletContextEvent sce) {
// Nothing to do here
}
}