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package org.atmosphere.container;
import org.apache.catalina.CometEvent;
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.Broadcaster;
import org.atmosphere.cpr.CometSupport;
import org.jboss.servlet.http.HttpEvent;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
/**
* This class gets used when the {@link AtmosphereServlet} fails to autodetect
* the Servlet Container we are running on.
* <p/>
* This {@link CometSupport} implementation uses a blocking approach, meaning
* the request thread will be blocked until another Thread invoke the
* {@link Broadcaster#broadcast}
*
* @author Jeanfrancois Arcand
*/
public class BlockingIOCometSupport extends AsynchronousProcessor {
private static final Logger logger = LoggerFactory.getLogger(BlockingIOCometSupport.class);
protected static final String LATCH = "org.atmosphere.container.BlockingIOCometSupport.latch";
protected final ConcurrentHashMap<Integer, CountDownLatch> latchs
= new ConcurrentHashMap<Integer, CountDownLatch>();
public BlockingIOCometSupport(AtmosphereConfig config) {
super(config);
}
/**
* {@inheritDoc}
*/
public Action service(HttpServletRequest req, HttpServletResponse res)
throws IOException, ServletException {
Action action = null;
try {
action = suspended(req, res);
if (action.type == Action.TYPE.SUSPEND) {
logger.debug("Suspending response: {}", res);
suspend(action, req, res);
} else if (action.type == Action.TYPE.RESUME) {
logger.debug("Resuming response: {}", res);
int latchId = (req.getAttribute(LATCH) == null ? 0 : (Integer)req.getAttribute(LATCH));
if (req.getSession(true).getAttribute(LATCH) != null) {
latchId = (Integer) req.getSession(true).getAttribute(LATCH);
}
CountDownLatch latch = latchs.get(latchId);
if (latch == null && req.getAttribute(AtmosphereResourceImpl.PRE_SUSPEND) == null) {
logger.debug("response wasn't suspended: {}", res);
return action;
}
latch.countDown();
Action nextAction = resumed(req, res);
if (nextAction.type == Action.TYPE.SUSPEND) {
logger.debug("Suspending after resuming response: {}", res);
suspend(action, req, res);
}
}
} finally {
CometEvent event = (CometEvent) req.getAttribute(TomcatCometSupport.COMET_EVENT);
if (event != null) {
event.close();
}
HttpEvent he = (HttpEvent) req.getAttribute(JBossWebCometSupport.HTTP_EVENT);
if (he != null) {
he.close();
}
}
return action;
}
/**
* Suspend the connection by blocking the current {@link Thread}
*
* @param action The {@link org.atmosphere.cpr.AtmosphereServlet.Action}
* @param req the {@link HttpServletRequest}
* @param res the {@link HttpServletResponse}
* @throws java.io.IOException
* @throws javax.servlet.ServletException
*/
protected void suspend(Action action, HttpServletRequest req, HttpServletResponse res)
throws IOException, ServletException {
CountDownLatch latch = new CountDownLatch(1);
int hash = latch.hashCode();
req.setAttribute(LATCH, hash);
latchs.put(hash, latch);
if (supportSession()) {
// Store as well in the session in case the resume operation
// happens outside the AtmosphereHandler.onStateChange scope.
req.getSession().setAttribute(String.valueOf(req.hashCode()), hash);
}
try {
if (action.timeout != -1) {
latch.await(action.timeout, TimeUnit.MILLISECONDS);
} else {
latch.await();
}
} catch (InterruptedException ex) {
logger.debug("", ex);
} finally {
latchs.remove(hash);
timedout(req, res);
}
}
@Override
public Action cancelled(HttpServletRequest req, HttpServletResponse res)
throws IOException, ServletException {
int latchId = -1;
if (req.getAttribute(LATCH) != null) {
latchId = (Integer) req.getAttribute(LATCH);
}
CountDownLatch latch = latchs.remove(latchId);
Action a = super.cancelled(req,res);
latch.countDown();
return a;
}
/**
* {@inheritDoc}
*/
@Override
public void action(AtmosphereResourceImpl actionEvent) {
try {
super.action(actionEvent);
if (actionEvent.action().type == Action.TYPE.RESUME && actionEvent.isInScope()) {
int latchId = -1;
HttpServletRequest req = actionEvent.getRequest();
if (req.getAttribute(LATCH) != null) {
latchId = (Integer) req.getAttribute(LATCH);
}
if (latchId == -1 && supportSession()) {
if (req.getSession().getAttribute(LATCH) != null) {
latchId = (Integer) req.getSession().getAttribute(LATCH);
}
}
String s = config.getInitParameter(AtmosphereServlet.RESUME_AND_KEEPALIVE);
if (latchId != -1 && (s == null || s.equalsIgnoreCase("false"))) {
CountDownLatch latch = latchs.remove(latchId);
if (latch == null) {
logger.error("Unable to resume the suspended connection with latchId: {}", latchId);
}
else {
latch.countDown();
}
}
else if (req.getAttribute(AtmosphereResourceImpl.PRE_SUSPEND) == null) {
logger.error("Unable to resume the suspended connection");
}
}
}
catch (Exception ex) {
logger.error("", ex);
}
}
}