org.atmosphere.cpr.Meteor Maven / Gradle / Ivy
/*
* Copyright 2017 Async-IO.org
*
* 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 org.atmosphere.cpr;
import com.vaadin.external.org.slf4j.Logger;
import com.vaadin.external.org.slf4j.LoggerFactory;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.List;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import static org.atmosphere.cpr.AtmosphereResourceImpl.METEOR;
import static org.atmosphere.cpr.FrameworkConfig.ATMOSPHERE_RESOURCE;
/**
* A {@link Meteor} is a simple class that can be used from a {@link javax.servlet.Servlet}
* to suspend, broadcast and resume responses. A {@link Meteor} can be created by invoking
* the build() method.
*
* Meteor.build(HttpServletRequest).suspend(-1);
*
* A Meteor is usually created when an application needs to suspend a response.
* A Meteor instance can then be cached and re-used later for either
* broadcasting a message, or when an application needs to resume the
* suspended response.
*
* @author Jeanfrancois Arcand
*/
public class Meteor {
private static final Logger logger = LoggerFactory.getLogger(Meteor.class);
private final AtmosphereResource r;
private Object o;
private AtomicBoolean isDestroyed = new AtomicBoolean(false);
private Meteor(AtmosphereResource r,
List l, Serializer s) {
this.r = r;
this.r.setSerializer(s);
if (l != null) {
for (BroadcastFilter f : l) {
this.r.getBroadcaster().getBroadcasterConfig().addFilter(f);
}
}
}
/**
* Retrieve an instance of {@link Meteor} based on the {@link HttpServletRequest}.
*
* @param r {@link HttpServletRequest}
* @return a {@link Meteor} or null if not found
*/
public static Meteor lookup(HttpServletRequest r) {
Object o = r.getAttribute(METEOR);
return o == null ? null : Meteor.class.isAssignableFrom(o.getClass()) ? Meteor.class.cast(o) : null;
}
/**
* Create a {@link Meteor} using the {@link HttpServletRequest}.
*
* @param r an {@link HttpServletRequest}
* @return a {@link Meteor} than can be used to resume, suspend and broadcast {@link Object}
*/
public final static Meteor build(HttpServletRequest r) {
return build(r, null);
}
/**
* Create a {@link Meteor} using the {@link HttpServletRequest} and use the
* {@link Serializer} for writing the result of a broadcast operation using
* the {@link HttpServletResponse}.
*
* @param r an {@link HttpServletRequest}
* @param s a {@link Serializer} used when writing broadcast events
* @return a {@link Meteor} than can be used to resume, suspend and broadcast {@link Object}
*/
public final static Meteor build(HttpServletRequest r, Serializer s) {
return build(r, null, s);
}
/**
* Create a {@link Meteor} using the {@link HttpServletRequest} and use a list of
* {@link BroadcastFilter} and {@link Serializer} for writing the result
* of a broadcast operation the {@link HttpServletResponse}.
*
* @param req an {@link HttpServletRequest}
* @param l a list of {@link BroadcastFilter}
* @param s a {@link Serializer} used when writing broadcast events
* @return a {@link Meteor} than can be used to resume, suspend and broadcast {@link Object}
*/
public final static Meteor build(HttpServletRequest req, List l, Serializer s) {
return build(req, Broadcaster.SCOPE.APPLICATION, l, s);
}
/**
* Create a {@link Meteor} using the {@link HttpServletRequest} and use a list of
* {@link BroadcastFilter} and {@link Serializer} for writing the result
* of a broadcast operation the {@link HttpServletResponse}.
*
* @param req an {@link HttpServletRequest}
* @param scope the {@link Broadcaster.SCOPE}}
* @param l a list of {@link BroadcastFilter}
* @param s a {@link Serializer} used when writing broadcast events
* @return a {@link Meteor} than can be used to resume, suspend and broadcast {@link Object}
*/
public final static Meteor build(HttpServletRequest req, Broadcaster.SCOPE scope,
List l, Serializer s) {
AtmosphereResource r =
(AtmosphereResource)
req.getAttribute(ATMOSPHERE_RESOURCE);
if (r == null) throw new IllegalStateException("MeteorServlet not defined in web.xml");
Broadcaster b = null;
if (scope == Broadcaster.SCOPE.REQUEST) {
try {
BroadcasterFactory f = r.getAtmosphereConfig().getBroadcasterFactory();
b = f.get(DefaultBroadcaster.class, DefaultBroadcaster.class.getSimpleName()
+ r.getAtmosphereConfig().uuidProvider().generateUuid());
} catch (Throwable t) {
throw new RuntimeException(t);
}
b.setScope(scope);
r.setBroadcaster(b);
req.setAttribute(AtmosphereResourceImpl.SKIP_BROADCASTER_CREATION, Boolean.TRUE);
}
Meteor m = new Meteor(r, l, (s != null ? s : r.getSerializer()));
req.setAttribute(METEOR, m);
return m;
}
/**
* Suspend the underlying {@link HttpServletResponse}. Passing a value of -1
* suspends the response forever.
*
* @param l the maximum time a response stay suspended
* @return {@link Meteor}
*/
public Meteor suspend(long l) {
if (destroyed()) return null;
r.suspend(l);
return this;
}
/**
* Resume the Meteor after the first broadcast operation. This is useful when long-polling is used.
*
* @param resumeOnBroadcast
* @return this
*/
public Meteor resumeOnBroadcast(boolean resumeOnBroadcast) {
r.resumeOnBroadcast(resumeOnBroadcast);
return this;
}
/**
* Return the current {@link org.atmosphere.cpr.AtmosphereResource.TRANSPORT}. The transport needs to be
* explicitly set by the client by adding the appropriate {@link HeaderConfig#X_ATMOSPHERE_TRANSPORT} value,
* which can be long-polling, streaming, websocket or JSONP.
*
* @return
*/
public AtmosphereResource.TRANSPORT transport() {
return r.transport();
}
/**
* Suspend the underlying {@link HttpServletResponse}. Passing a value of -1
* suspends the response forever.
*
* @param timeout the maximum time a response stay suspended
* @param timeunit The time unit of the timeout value
* @return {@link Meteor}
*/
public Meteor suspend(long timeout, TimeUnit timeunit) {
if (destroyed()) return null;
r.suspend(timeout, timeunit);
return this;
}
/**
* Resume the underlying {@link HttpServletResponse}.
*
* @return {@link Meteor}
*/
public Meteor resume() {
if (destroyed()) return null;
r.resume();
return this;
}
/**
* Broadcast an {@link Object} to all suspended responses.
*
* @param o an {@link Object}
* @return {@link Meteor}
*/
public Meteor broadcast(Object o) {
if (destroyed()) return null;
r.getBroadcaster().broadcast(o);
return this;
}
/**
* Schedule a periodic broadcast, in seconds.
*
* @param o an {@link Object}
* @param period period in seconds
* @return {@link Meteor}
*/
public Meteor schedule(Object o, long period) {
if (destroyed()) return null;
r.getBroadcaster().scheduleFixedBroadcast(o, period, TimeUnit.SECONDS);
return this;
}
/**
* Schedule a delayed broadcast, in seconds.
*
* @param o an {@link Object}
* @param period period in seconds
* @return {@link Meteor}
*/
public Meteor delayBroadadcast(Object o, long period) {
if (destroyed()) return null;
r.getBroadcaster().delayBroadcast(o, period, TimeUnit.SECONDS);
return this;
}
/**
* Return the underlying {@link Broadcaster}.
*
* @return
*/
public Broadcaster getBroadcaster() {
if (destroyed()) return null;
return r.getBroadcaster();
}
/**
* Set a {@link Broadcaster} instance.
*
* @param b
*/
public void setBroadcaster(Broadcaster b) {
if (destroyed()) return;
r.setBroadcaster(b);
}
/**
* Return an {@link Object} with this {@link Meteor}.
*
* @return the {@link Object}
*/
public Object attachement() {
return o;
}
/**
* Attach an {@link Object} with this {@link Meteor}.
*
* @return the {@link Object}
*/
public void attach(Object o) {
this.o = o;
}
/**
* Add a {@link AtmosphereResourceEventListener} which gets invoked when
* responses are resuming, when the remote client closes the connection or
* when the a {@link Broadcaster#broadcast} operations occurs.
*
* @param e an instance of {@link AtmosphereResourceEventListener}
*/
public Meteor addListener(AtmosphereResourceEventListener e) {
if (!destroyed()) {
r.addEventListener(e);
}
return this;
}
/**
* Remove a {@link AtmosphereResourceEventListener} which gets invoked when
* a response is resuming, when the remote client closes the connection or
* when the a {@link Broadcaster#broadcast} operations occurs.
*
* @param e an instance of {@link AtmosphereResourceEventListener}
*/
public Meteor removeListener(AtmosphereResourceEventListener e) {
if (!destroyed()) {
r.removeEventListener(e);
}
return this;
}
/**
* Mark this instance as destroyed. No more operations will be allowed.
*/
public void destroy() {
isDestroyed.set(true);
}
private boolean destroyed() {
if (isDestroyed.get()) {
logger.debug("This Meteor is destroyed and cannot be used.");
return true;
}
return false;
}
/**
* Return the underlying {@link AtmosphereResource}.
*
* @return the underlying {@link AtmosphereResource}
*/
public AtmosphereResource getAtmosphereResource() {
return r;
}
/**
* Return the {@link org.atmosphere.cpr.AtmosphereConfig}
* @return the {@link org.atmosphere.cpr.AtmosphereConfig}
*/
public AtmosphereConfig getAtmosphereConfig() {
return r.getAtmosphereConfig();
}
}