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package org.atmosphere.container;
import org.apache.catalina.CometEvent;
import org.apache.catalina.CometEvent.EventType;
import org.atmosphere.cpr.AsynchronousProcessor;
import org.atmosphere.cpr.AtmosphereResourceImpl;
import org.atmosphere.cpr.AtmosphereServlet;
import org.atmosphere.cpr.AtmosphereServlet.Action;
import org.atmosphere.cpr.AtmosphereServlet.AtmosphereConfig;
import org.atmosphere.cpr.CometSupport;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.logging.Level;
/**
* Comet Portable Runtime implementation on top of Tomcat AIO.
*
* @author Jeanfrancois Arcand
*/
public class TomcatCometSupport extends AsynchronousProcessor implements CometSupport<AtmosphereResourceImpl> {
public final static String COMET_EVENT = "CometEvent";
private final static IllegalStateException unableToDetectComet
= new IllegalStateException(unableToDetectComet());
// Client disconnection is broken on Tomcat.
private final ConcurrentLinkedQueue<CometEvent> resumed
= new ConcurrentLinkedQueue<CometEvent>();
public TomcatCometSupport(AtmosphereConfig config) {
super(config);
}
/**
* Invoked by the Tomcat AIO when a Comet request gets detected.
*
* @param req the {@link javax.servlet.http.HttpServletRequest}
* @param res the {@link HttpServletResponse}
* @throws java.io.IOException
* @throws javax.servlet.ServletException
*/
public Action service(HttpServletRequest req, HttpServletResponse res)
throws IOException, ServletException {
CometEvent event = (CometEvent) req.getAttribute(COMET_EVENT);
// Comet is not enabled.
if (event == null) {
throw unableToDetectComet;
}
Action action = null;
// For now, we are just interested in CometEvent.READ
if (event.getEventType() == EventType.BEGIN) {
action = suspended(req, res);
if (action.type == Action.TYPE.SUSPEND) {
if (logger.isLoggable(Level.FINE)) {
logger.fine("Suspending " + res);
}
// Do nothing except setting the times out
try {
if (action.timeout != -1) {
event.setTimeout((int) action.timeout);
} else {
event.setTimeout(Integer.MAX_VALUE);
}
} catch (UnsupportedOperationException ex) {
// Swallow s Tomcat APR isn't supporting time out
// TODO: Must implement the same functionality using a
// Scheduler
}
} else if (action.type == Action.TYPE.RESUME) {
if (logger.isLoggable(Level.FINE)) {
logger.fine("Resuming " + res);
}
event.close();
} else {
event.close();
}
} else if (event.getEventType() == EventType.READ) {
// Not implemented
} else if (event.getEventSubType() == CometEvent.EventSubType.CLIENT_DISCONNECT) {
if (logger.isLoggable(Level.FINE)) {
logger.fine("Client closed connection " + res);
}
if (!resumed.remove(event)) {
if (logger.isLoggable(Level.FINE)) {
logger.fine("Client closed connection " + res);
}
action = cancelled(req, res);
} else {
if (logger.isLoggable(Level.FINE)) {
logger.fine("Cancelling " + res);
}
}
event.close();
} else if (event.getEventSubType() == CometEvent.EventSubType.TIMEOUT) {
if (logger.isLoggable(Level.FINE)) {
logger.fine("Timing out " + res);
}
action = timedout(req, res);
event.close();
} else if (event.getEventType() == EventType.ERROR) {
event.close();
} else if (event.getEventType() == EventType.END) {
if (!resumed.remove(event)) {
if (logger.isLoggable(Level.FINE)) {
logger.fine("Client closed connection " + res);
}
action = cancelled(req, res);
} else {
if (logger.isLoggable(Level.FINE)) {
logger.fine("Cancelling " + res);
}
}
event.close();
}
return action;
}
/**
* {@inheritDoc}
*/
@Override
public void action(AtmosphereResourceImpl resource) {
super.action(resource);
if (resource.action().type == Action.TYPE.RESUME && resource.isInScope()) {
try {
CometEvent event = (CometEvent) resource.getRequest().getAttribute(COMET_EVENT);
if (event == null) return;
resumed.offer(event);
// Resume without closing the underlying suspended connection.
if (config.getInitParameter(AtmosphereServlet.RESUME_AND_KEEPALIVE) == null
|| config.getInitParameter(AtmosphereServlet.RESUME_AND_KEEPALIVE).equalsIgnoreCase("false")) {
event.close();
}
} catch (IOException ex) {
if (logger.isLoggable(Level.FINE)) {
logger.log(Level.FINE, "", ex);
}
}
}
}
@Override
public Action cancelled(HttpServletRequest req, HttpServletResponse res)
throws IOException, ServletException {
Action action = super.cancelled(req,res);
if (req.getAttribute(MAX_INACTIVE) != null && Long.class.cast(req.getAttribute(MAX_INACTIVE)) == -1) {
CometEvent event = (CometEvent) req.getAttribute(COMET_EVENT);
if (event == null) return action;
resumed.offer(event);
event.close();
}
return action;
}
/**
* Tomcat was unable to detect Atmosphere's CometProcessor implementation.
*
* @return an error message describing how to fix the issue.
*/
private static String unableToDetectComet() {
StringBuilder sb = new StringBuilder();
sb.append("Tomcat failed to detect this is a Comet application because context.xml ");
sb.append("is missing or the Http11NioProtocol Connector is not enabled.");
sb.append("\nIf that's not the case, you can also remove META-INF/context.xml and WEB-INF/lib/atmosphere-compat-tomcat.jar");
return sb.toString();
}
}