com.sun.grizzly.comet.CometContext Maven / Gradle / Ivy
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package com.sun.grizzly.comet;
import com.sun.grizzly.comet.concurrent.DefaultConcurrentCometHandler;
import com.sun.grizzly.http.SelectorThread;
import java.io.IOException;
import java.nio.channels.SelectionKey;
import java.util.Iterator;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* The main object used by {@link CometHandler} and {@link Servlet} to push information
* amongs suspended request/response. The {@link CometContext} is always available for {@link CometHandler}
* and can be used to {@link #notify}, or share information with other
* {@link CometHandler}. This is the equivalent of server push as the CometContext
* will invoke all registered CometHandler ({@link #addCometHandler}) sequentially
* or using a thread pool when the {@link #setBlockingNotification} is set to
* false
*
* A CometContext can be considered as a topic where CometHandler register for
* information. A CometContext can be shared amongs Servlet of the same application,
* or globally accros all deployed web applications. Normally, a CometContext
* is created using a topic's name like:
*
* CometEngine ce = CometEngine.getEngine();
* CometContext cc = ce.registerContext("MyTopic");
* cc.setBlockingNotification(false); // Use multiple thread to execute the server push
*
* and then inside a {@link Servlet.service} method, you just need to call:
*
* cc.addCometListener(myNewCometListener());
* cc.notify("I'm pushing data to all registered CometHandler");
*
*
* As soom as {@link #addCometHandler} is invoked, Grizzly will automatically
* suspend the request/response (will not commit the response).
* A response can be resumed by invoking {@link #resumeCometHandler},
* which will automatically commit the response and remove the associated
* CometHandler from the CometContext.
*
* A CometContext uses a {@link NotificationHandler} to invoke, using the calling
* thread or a Grizzly thread pool, all CometHandler than have been added using the
* {@link #addCometHandler}. A {@link NotificationHandler} can be used to filter
* or transform the content that will eventually be pushed back to all connected
* clients. You can also use a {@link NotificationHandler} to throttle push like
* invoking only a subset of the CometHandler, etc.
*
* Idle suspended connection can be timed out by configuring the {@link #setExpirationDelay(int)}.
* The value needs to be in milliseconds. If there is no I/O operations and no
* invokation of {@link #notify} during the expiration delay, Grizzly
* will resume all suspended connection. An application will have a chance to
* send back data using the connection as Grizzly will invoke the {@link CometHandler#onInterrupt}
* before resuming the connection. Note that setting the expiration delay to -1
* disable the above mechanism, e.g. idle connection will never get resumed
* by Grizzly.
*
*
*
* Attributes can be added/removed the same way {@link HttpServletSession}
* is doing. It is not recommended to use attributes if this
* {@link CometContext} is not shared amongs multiple
* context path (uses {@link HttpServletSession} instead).
*
* @author Jeanfrancois Arcand
* @author Gustav Trede
*/
public class CometContext {
/**
* Generic error message
*/
protected final static String INVALID_COMET_HANDLER = "CometHandler cannot be null. "
+ "This CometHandler was probably resumed and an invalid "
+ "reference was made to it.";
protected final static String ALREADY_REMOVED =
"CometHandler already been removed or invalid.";
/**
* Main logger
*/
protected final static Logger logger = SelectorThread.logger();
/**
* Attributes placeholder.
*/
private final ConcurrentHashMap attributes;
/**
* The context path associated with this instance.
*/
protected String topic;
/**
* The {@link CometSelector} used to register {@link SelectionKey}
* for upcoming bytes.
*/
protected CometSelector cometSelector;
/**
* The {@link CometContext} continuationType. See {@link CometEngine}
*/
protected int continuationType = CometEngine.AFTER_SERVLET_PROCESSING;
/**
* The default delay expiration before a {@link CometContext}'s
* {@link CometHandler} are interrupted.
*/
private long expirationDelay = 30 * 1000;
/**
* true if the caller of {@link #notify} should block when
* notifying other CometHandler.
*/
protected boolean blockingNotification = false;
/**
* The default NotificationHandler.
*/
protected NotificationHandler notificationHandler;
/**
* timestamp for last performed resetSuspendidletimeout.
* used to limit the frequency of actual performed resets.
*/
private volatile long lastIdleReset;
/**
* Current associated list of {@link CometTask}
*/
protected final ConcurrentHashMap activeTasks;
/**
* The list of registered {@link CometHandler}
*/
protected final ConcurrentHashMap handlers;
private final CometEvent eventInterrupt;
private final CometEvent eventInitialize;
private static final IllegalStateException ISE = new IllegalStateException(INVALID_COMET_HANDLER);
private static final IllegalStateException cometNotEnabled =
new IllegalStateException("Make sure you have enabled Comet " +
"or make sure the Thread invoking that method is the same " +
"as the Servlet.service() Thread.");
// ---------------------------------------------------------------------- //
/**
* Create a new instance
* @param topic the context path
* @param type when the Comet processing will happen (see {@link CometEngine}).
*/
public CometContext(String topic, int continuationType) {
this.topic = topic;
this.continuationType = continuationType;
this.attributes = new ConcurrentHashMap();
this.handlers = new ConcurrentHashMap(16,0.75f,64);
this.activeTasks = new ConcurrentHashMap(16,0.75f,64);
this.eventInterrupt = new CometEvent(CometEvent.INTERRUPT,this);
this.eventInitialize = new CometEvent(CometEvent.INITIALIZE,this);
}
/**
* Get the context path associated with this instance.
* @return topic the context path associated with this instance
* @deprecated - use getTopic.
*/
public String getContextPath(){
return getTopic();
}
/**
* Get the topic representing this instance with this instance. This is
* the value to uses when invoking {@link CometEngine#getCometContext}
* @return topic the topic associated with this instance
*/
public String getTopic(){
return topic;
}
/**
* Add an attibute.
* @param key the key
* @param value the value
*/
public void addAttribute(Object key, Object value){
attributes.put(key,value);
}
/**
* Retrieve an attribute.
* @param key the key
* @return Object the value.
*/
public Object getAttribute(Object key){
return attributes.get(key);
}
/**
* Remove an attribute.
* @param key the key
* @return Object the value
*/
public Object removeAttribute(Object key){
return attributes.remove(key);
}
/**
* Add a {@link CometHandler}. The underlying {@link HttpServletResponse} will
* not get commited until {@link CometContext#resumeCometHandler(CometHandler)}
* is invoked, unless the {@link CometContext#setExoirationDelay(int)} expires.
* If set to alreadySuspended is set to true, no I/O operations are allowed
* inside the {@link CometHandler} as the underlying {@link HttpServletResponse}
* has not been suspended. Adding such {@link CometHandler} is usefull only when
* no I/O operations on the {@link HttpServletResponse} are required. Examples
* include calling a remote EJB when a push operations happens, storing
* data inside a database, etc.
*
* @param handler a new {@link CometHandler}
* @param alreadySuspended Add the Comethandler but don't suspend
* the {@link HttpServletResponse}. If set to true, no
* I/O operations are allowed inside the {@link CometHandler} as the
* underlying {@link HttpServletResponse} has not been suspended, unless
* the {@link CometHandler} is shared amongs more than one {@link CometContext}
*
* @return The {@link CometHandler#hashCode} value.
*/
public int addCometHandler(CometHandler handler, boolean alreadySuspended){
if (handler == null){
throw ISE;
}
if (!CometEngine.getEngine().isCometEnabled()){
throw cometNotEnabled;
}
handlers.put(handler, CometEngine.dumykey);
// is it ok that we only manage one adcomethandler call ?
CometTask cometTask = new CometTask();
cometTask.setCometContext(this);
cometTask.setCometHandler(handler);
cometTask.setSuspended(alreadySuspended);
CometEngine.updatedContexts.set(cometTask);
return handler.hashCode();
}
/**
* Add a {@link CometHandler} which will starts the process of suspending
* the underlying response. The underlying {@link HttpServletResponse} will
* not get commited until {@link CometContext#resumeCometHandler(CometHandler)}
* is invoked, unless the {@link CometContext#setExoirationDelay(int)} expires.
* @param handler a new {@link CometHandler}
*/
public int addCometHandler(CometHandler handler){
return addCometHandler(handler,false);
}
/**
* Retrieve a {@link CometHandler} using its based on its {@link CometHandler#hashCode};
*/
public CometHandler getCometHandler(int hashCode){
for (CometHandler handler:handlers.keySet()){
if (handler.hashCode() == hashCode )
return handler;
}
return null;
}
/**
* Recycle this object.
*/
public void recycle(){
handlers.clear();
attributes.clear();
activeTasks.clear();
topic = null;
}
/**
* adds a {@link CometHandler} to the active set
* @param handler {@link CometHandler}
* @param cometKey {@link SelectionKey}
*/
protected void addActiveHandler(CometHandler handler, SelectionKey cometKey){
handlers.put(handler, cometKey);
}
/**
* Invoke a {@link CometHandler} using the {@link CometEvent}
* @param event - {@link CometEvent}
* @param cometHandler - {@link CometHandler}
* @throws java.io.IOException
*/
protected void invokeCometHandler(CometEvent event, CometHandler cometHandler) throws IOException{
if (cometHandler == null){
throw ISE;
}
event.setCometContext(this);
if (cometHandler instanceof DefaultConcurrentCometHandler){
((DefaultConcurrentCometHandler)cometHandler).EnQueueEvent(event);
}else{
cometHandler.onEvent(event);
}
}
/**
* Remove a {@link CometHandler}. If the continuation (connection)
* associated with this {@link CometHandler} no longer have
* {@link CometHandler} associated to it, it will be resumed by Grizzly
* by calling {@link CometContext#resumeCometHandler()}
* @return true if the operation succeeded.
*/
public boolean removeCometHandler(CometHandler handler){
return removeCometHandler(handler,true);
}
/**
* Remove a {@link CometHandler}. If the continuation (connection)
* associated with this {@link CometHandler} no longer have
* {@link CometHandler} associated to it, it will be resumed.
* @param handler The CometHandler to remove.
* @param resume True is the connection can be resumed if no CometHandler
* are associated with the underlying SelectionKey.
* @return true if the operation succeeded.
*/
public boolean removeCometHandler(CometHandler handler,boolean resume){
CometEngine.updatedContexts.set(null);
SelectionKey key = handlers.remove(handler);
if (key != null){
if (resume){
CometEngine.getEngine().flushPostExecute(
((CometTask)key.attachment()).getAsyncProcessorTask());
}
return true;
}
return false;
}
/**
* Remove a {@link CometHandler} based on its hashcode. Return true
* if the operation was sucessfull.
* O(n) performance.
* @param hashCode The hashcode of the CometHandler to remove.
* @return true if the operation succeeded.
*/
public boolean removeCometHandler(int hashCode){
CometEngine.updatedContexts.set(null);
Iterator iterator = handlers.keySet().iterator();
CometHandler handler = null;
while (iterator.hasNext()){
handler = iterator.next();
if (handler.hashCode() == hashCode){
SelectionKey key = handlers.get(handler);
if (key == null){
logger.warning(ALREADY_REMOVED);
return false;
}
iterator.remove();
return true;
}
}
return false;
}
/**
* Resume the Comet request and remove it from the active {@link CometHandler} list. Once resumed,
* a CometHandler must never manipulate the {@link HttpServletRequest} or {@link HttpServletResponse} as
* those object will be recycled and may be re-used to serve another request.
*
* If you cache them for later reuse by another thread there is a
* possibility to introduce corrupted responses next time a request is made.
* @param handler The CometHandler to resume.
* @return true if the operation succeeded.
*/
public boolean resumeCometHandler(CometHandler handler){
return resumeCometHandler(handler,true);
}
/**
* Resume the suspended response. A response can only be suspended when
* {@link CometContext#addCometHandler} was called first.
*
* @param handler The CometHandler associated with the current continuation.
* @param remove true if the CometHandler needs to be removed.
* @return true if the operation succeeded.
*/
protected boolean resumeCometHandler(CometHandler handler, boolean remove){
CometEngine.updatedContexts.set(null);
boolean b= cometSelector.cancelKey(handlers.get(handler), false, remove, false);
// Try a second time to locate the associated CometTask
if (!b){
for (CometTask cometTask:activeTasks.keySet()){
if (cometTask.getCometHandler() == handler){
interrupt(cometTask, remove, false);
CometEngine.getEngine().flushPostExecute(
cometTask.getAsyncProcessorTask());
activeTasks.remove(cometTask);
return true;
}
}
}
return b;
}
/**
* Interrupt a {@link CometHandler} by invoking {@link CometHandler#onInterrupt}
*/
protected boolean interrupt(CometTask task,boolean removeCometHandler,
boolean notifyInterrupt) {
boolean status = true;
try{
if (removeCometHandler){
status = (handlers.remove(task.getCometHandler()) != null);
if (status && notifyInterrupt){
task.getCometHandler().onInterrupt(eventInterrupt);
}else{
logger.fine(ALREADY_REMOVED);
}
}
} catch (Throwable ex){
status = false;
logger.log(Level.FINE,"Unable to interrupt",ex);
}finally{
activeTasks.remove(task);
return status;
}
}
/**
* Return true if this {@link CometHandler} is still active, e.g. there is
* still a suspended connection associated with it.
*
* @return true
*/
public boolean isActive(CometHandler handler){
return handlers.containsKey(handler) || CometEngine.updatedContexts.get() != null;
}
/**
* Notify all {@link CometHandler}. All
* {@link CometHandler.onEvent()} will be invoked with a {@link CometEvent}
* of type NOTIFY.
* @param attachment An object shared amongst {@link CometHandler}.
*/
public void notify(final E attachment) throws IOException{
notify(attachment, CometEvent.NOTIFY);
}
/**
* Notify a single {@link CometHandler}. The {@link CometEvent.getType()}
* will determine which {@link CometHandler} method will be invoked:
*
* CometEvent.INTERRUPT -> {@link CometHandler#onInterrupt}
* CometEvent.NOTIFY -> {@link CometHandler#onEvent}
* CometEvent.INITIALIZE -> {@link CometHandler#onInitialize}
* CometEvent.TERMINATE -> {@link CometHandler#onTerminate}
* CometEvent.READ -> {@link CometHandler#onEvent}
*
* @param attachment An object shared amongst {@link CometHandler}.
* @param type The type of notification.
* @param cometHandlerID Notify a single CometHandler.
* @deprecated - use notify(attachment,eventType,CometHandler;
*/
public void notify(final E attachment,final int eventType,final int cometHandlerID)
throws IOException{
notify(attachment,eventType,getCometHandler(cometHandlerID));
}
/**
* Notify a single {@link CometHandler#onEvent(CometEvent}.
* @param attachment An object shared amongst {@link CometHandler}.
* @param {@link CometHandler} to notify.
*/
public void notify(final E attachment,final CometHandler cometHandler)
throws IOException{
notify(attachment,CometEvent.NOTIFY,cometHandler);
}
/**
* Notify a single {@link CometHandler}. The {@link CometEvent.getType()}
* will determine which {@link CometHandler} method will be invoked:
*
* CometEvent.INTERRUPT -> {@link CometHandler#onInterrupt}
* CometEvent.NOTIFY -> {@link CometHandler#onEvent}
* CometEvent.INITIALIZE -> {@link CometHandler#onInitialize}
* CometEvent.TERMINATE -> {@link CometHandler#onTerminate}
* CometEvent.READ -> {@link CometHandler#onEvent}
*
* @param attachment An object shared amongst {@link CometHandler}.
* @param type The type of notification.
* @param {@link CometHandler} to notify.
*/
public void notify(final E attachment,final int eventType,final CometHandler cometHandler)
throws IOException{
if (cometHandler == null){
throw ISE;
}
CometEvent event = new CometEvent(eventType,this);
event.attach(attachment);
notificationHandler.setBlockingNotification(blockingNotification);
notificationHandler.notify(event,cometHandler);
if (event.getType() == CometEvent.TERMINATE
|| event.getType() == CometEvent.INTERRUPT) {
resumeCometHandler(cometHandler);
} else {
resetSuspendIdleTimeout();
}
}
/**
* Notify all {@link CometHandler}. The {@link CometEvent.getType()}
* will determine which {@link CometHandler}
* method will be invoked:
*
* CometEvent.INTERRUPT -> {@link CometHandler#onInterrupt}
* CometEvent.NOTIFY -> {@link CometHandler#onEvent}
* CometEvent.INITIALIZE -> {@link CometHandler#onInitialize}
* CometEvent.TERMINATE -> {@link CometHandler#onTerminate}
* CometEvent.READ -> {@link CometHandler#onEvent}
*
* @param attachment An object shared amongst {@link CometHandler}.
* @param type The type of notification.
*/
public void notify(final E attachment,final int eventType)
throws IOException{
CometEvent event = new CometEvent(eventType,this);
event.attach(attachment);
Iterator iterator = handlers.keySet().iterator();
notificationHandler.setBlockingNotification(blockingNotification);
notificationHandler.notify(event,iterator);
if (event.getType() == CometEvent.TERMINATE
|| event.getType() == CometEvent.INTERRUPT) {
while(iterator.hasNext()){
resumeCometHandler(iterator.next());
}
} else {
resetSuspendIdleTimeout();
}
}
/**
* Initialize the newly added {@link CometHandler}.
*
* @param attachment An object shared amongst {@link CometHandler}.
* @param type The type of notification.
* @param key The SelectionKey representing the CometHandler.
*/
protected void initialize(CometHandler handler) throws IOException {
handler.onInitialize(eventInitialize);
}
/**
* Reset the current timestamp on a suspended connection.
*/
protected void resetSuspendIdleTimeout(){
if (expirationDelay != -1){
long timestamp = System.currentTimeMillis();
// not threadsafe, but that will only lead to a few extra idle checks.
// it will still be a major win.
if (timestamp - lastIdleReset >= 1000){
lastIdleReset = timestamp;
for (CometTask cometTask:activeTasks.keySet()){
cometTask.setExpireTime(timestamp);
}
}
}
}
/**
* Register for asynchronous read event (CometEvent#READ}. As soon as Grizzly detects
* there is some bytes available for read, your {@link Comethandler#onEvent(CometEvent)} will be invoked.
* {@link CometEvent#attachment()} will return an instance of {@link CometReader}
* that can be used to asynchronously read the available bytes.
*
* If your client supports http pipelining,
* invoking this method might result in a state where your CometHandler
* is invoked with a {@link CometReader} that will read the next http request. In that
* case, it is strongly recommended to not use that method unless your
* CometHandler can handle the http request.
*
* @param handler The CometHandler that will be invoked.
*/
public boolean registerAsyncRead(CometHandler handler){
return doAsyncRegister(handler, SelectionKey.OP_READ);
}
/**
* Register for asynchronous write event (CometEvent#WRITE} .As soon as Grizzly detects
* there is some OS buffer available for write operations, your
* {@link Comethandler#onEvent(CometEvent)} will be invoked.
* {@link CometEvent#attachment()} will return an instance of {@link CometWriter}
* that can be used to asynchronously write the available bytes.
* @param handler The CometHandler that will be invoked.
*/
public boolean registerAsyncWrite(CometHandler handler){
return doAsyncRegister(handler, SelectionKey.OP_WRITE);
}
/**
* Register for asynchronous read or write I/O operations.
* @param handler the CometHandler that will be invoked
* @param interest The read or write interest.
* @return true if the operation worked.
*/
private boolean doAsyncRegister(CometHandler handler, int interest){
SelectionKey cometKey = null;
if (handler != null) {
cometKey = handlers.get(handler);
}
if (handler == null || cometKey == null) {
throw ISE;
}
CometTask cometTask = (CometTask)cometKey.attachment();
if (cometTask != null){
cometKey.interestOps(cometKey.interestOps() | interest);
if (interest == SelectionKey.OP_READ){
cometTask.setAsyncReadSupported(true);
}
cometTask.setComethandlerisAsyncregistered(true);
return true;
}
throw ISE;
}
/**
* Set the {@link CometSelector} associated with this instance.
* @param CometSelector the {@link CometSelector} associated with
* this instance.
*/
protected void setCometSelector(CometSelector cometSelector) {
this.cometSelector = cometSelector;
}
/**
* Helper.
*/
@Override
public String toString(){
return topic;
}
/**
* Return the {@link long} delay, in millisecond, before a request is resumed.
* @return long the {@link long} delay, in millisecond, before a request is resumed.
*/
public long getExpirationDelay() {
return expirationDelay;
}
/**
* Set the {@link long} delay before a request is resumed.
* @param expirationDelay the {@link long} delay before a request is resumed.
* Value is in milliseconds.
*/
public void setExpirationDelay(long expirationDelay) {
this.expirationDelay = expirationDelay;
}
/**
* Return the current list of active {@link CometHandler}
* @return the current list of active {@link CometHandler}
*/
public Set getCometHandlers(){
return handlers.keySet();
}
/**
* Add a {@link CometTask} to the active list.
* @param cometTask
*/
protected void addActiveCometTask(CometTask cometTask){
activeTasks.put(cometTask,Boolean.TRUE);
}
/**
* Return true if the invoker of {@link #notify} should block when
* notifying Comet Handlers.
*/
public boolean isBlockingNotification() {
return blockingNotification;
}
/**
* Set to true if the invoker of {@link #notify} should block when
* notifying Comet Handlers.
*/
public void setBlockingNotification(boolean blockingNotification) {
this.blockingNotification = blockingNotification;
}
/**
* Set the current {@link NotificationHandler}
* @param notificationHandler
*/
public void setNotificationHandler(NotificationHandler notificationHandler){
this.notificationHandler = notificationHandler;
}
/**
* Return the associated {@link NotificationHandler}
* @return
*/
public NotificationHandler getNotificationHandler(){
return notificationHandler;
}
/**
* Return the current set of active {@link CometTask}
* @return
*/
protected Set getActiveTasks() {
return activeTasks.keySet();
}
}
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