org.atmosphere.cpr.Meteor Maven / Gradle / Ivy
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package org.atmosphere.cpr;
import java.util.List;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.TimeUnit;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.atmosphere.handler.ReflectorServletProcessor;
import static org.atmosphere.handler.ReflectorServletProcessor.*;
/**
* A {@link Meteor} is a simple class that can be used from a {@link javax.servlet.Servlet}
* to suspend, broadcast and resume a response. A {@link Meteor} can be created by invoking
* the build() method.
*
* Meteor.build(HttpServletRequest).suspend(-1);
*
* A Meteor is usually created when an application need 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 final static ConcurrentHashMap cache =
new ConcurrentHashMap();
private AtmosphereResource r;
private Object o;
private Meteor(AtmosphereResource r,
List l, Serializer s){
this.r = r;
r.setSerializer(s);
if (l != null){
for(BroadcastFilter f: l) {
r.getBroadcaster().getBroadcasterConfig().addFilter(f);
}
}
cache.put(r.getRequest(), this);
}
/**
* 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){
return cache.get(r);
}
/**
* 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){
Meteor m = lookup(r);
if (m != null) return m;
return build(r,null);
}
/**
* Create a {@link Meteor} using the {@link HttpServletRequest} and use the
* {@link Serializer} for writting 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 writting 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 writting 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 = new DefaultBroadcaster();
b.setScope(scope);
r.setBroadcaster(b);
Meteor m = new Meteor(r,l,s);
return m;
}
/**
* Suspend the underlying {@link HttpServletResponse}. Passing value of -1
* suspend the response forever.
* @param l the maximum time a response stay suspended.
* @return {@link Meteor}
*/
public Meteor suspend(long l){
r.suspend(l);
return this;
}
/**
* Resume the underlying {@link HttpServletResponse}
* @return {@link Meteor}
*/
public Meteor resume(){
r.resume();
return this;
}
/**
* Broadcast an {@link Object} to all suspended response.
* @param o an {@link Object}
* @return {@link Meteor}
*/
public Meteor broadcast(Object o){
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){
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){
r.getBroadcaster().delayBroadcast(o, period, TimeUnit.SECONDS);
return this;
}
/**
* Return the underlying {@link Broadcaster}
* @return
*/
public Broadcaster getBroadcaster(){
return r.getBroadcaster();
}
/**
* 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
* response are resuming, when the remote client close the connection or
* when the a {@link Broadcast#broadcast} operations occurs.
* @param e an inatance of {@link AtmosphereResourceEventListener}
*/
public void addListener(AtmosphereResourceEventListener e){
if (!(r.getAtmosphereConfig().getAtmosphereHandler()
instanceof ReflectorServletProcessor)){
((ReflectorServletProcessor)r.getAtmosphereConfig()
.getAtmosphereHandler()).addEventListener(e);
} else {
throw new UnsupportedOperationException("Only supported when "
+ ReflectorServletProcessor.class.getName() + " is used");
}
}
}