org.directwebremoting.export
Class System

java.lang.Object
  org.directwebremoting.export.System

public class System
extends java.lang.Object

Various functions exported by DWR to help us with various book-keeping duties.

Author:

Joe Walker [joe at getahead dot ltd dot uk]

Field Summary

static java.lang.String

ATTRIBUTE_DWRSESSIONID Session attribute for DWRSESSIONID

Constructor Summary

System()

Method Summary

void	activateCallback(java.lang.String key, RealRawData data) Used by reverse ajax proxies to send data back to the server
void	checkHeartbeat() A method designed to be called when the client is offline.
java.lang.String	generateId() Generates and returns a new unique id suitable to use for the CSRF session cookie.
void	pageLoaded() A method designed to be called on page load so the client knows about the http and script sessions.
void	pageUnloaded() Call ScriptSession.invalidate() on the ScriptSession that called this method.
void	publish(java.lang.String topic, RealRawData data) Something has published to the client side 'hub' and we're getting to know about it.
void	subscribe(java.lang.String topic, java.lang.String subscriptionId) Ensure that the clients know about server publishes
boolean	unsubscribe(java.lang.String subscriptionId) Stop notifications of against a subscription id

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ATTRIBUTE_DWRSESSIONID

public static final java.lang.String ATTRIBUTE_DWRSESSIONID

Session attribute for DWRSESSIONID

See Also:

Constant Field Values

Constructor Detail

System

public System()

Method Detail

generateId

public java.lang.String generateId()

Generates and returns a new unique id suitable to use for the CSRF session cookie. This method is itself exempted from CSRF checking.

pageLoaded

public void pageLoaded()

A method designed to be called on page load so the client knows about the http and script sessions. This method doesn't actually do anything however it does allow DWR's script session checking code to work

checkHeartbeat

public void checkHeartbeat()

A method designed to be called when the client is offline. When the server is back online this method will return immediately so reverse AJAX polling may resume.

pageUnloaded

public void pageUnloaded()

Call ScriptSession.invalidate() on the ScriptSession that called this method. Used by the page unloader.

activateCallback

public void activateCallback(java.lang.String key,
                             RealRawData data)

Used by reverse ajax proxies to send data back to the server

Parameters:

key - The unique id under which a callback is registered

data - The data to decode and pass to the callback

publish

public void publish(java.lang.String topic,
                    RealRawData data)

Something has published to the client side 'hub' and we're getting to know about it.

Parameters:

topic - The topic that has been published to

data - The published data

subscribe

public void subscribe(java.lang.String topic,
                      java.lang.String subscriptionId)

Ensure that the clients know about server publishes

Parameters:

topic - The topic being subscribed to

subscriptionId - The ID to pass back to link to client side data

unsubscribe

public boolean unsubscribe(java.lang.String subscriptionId)

Stop notifications of against a subscription id

Parameters:

subscriptionId - The ID to pass back to link to client side data

Returns:

true iff someone was unsubscribed