pushlet笔记 3种发布方式

1.2.1. Direct Publishing (local)

Your application may directly publish Events by using /src/nl/justobjects/pushlet/core/Dispatcher.getInstance().java . Since Dispatcher is (currently) a Singleton, sending the Event is a matter of callingDispatcher.getInstance().multicast()/unicast()/broadcast() .

The other two methods (EventSource and Pushlet protocol) will eventually call Dispatcher.getInstance().multicast()/unicast()/broadcast() .

Note that in order to call Dispatcher.getInstance().multicast()/unicast()/broadcast() , your class needs to be in the same classloader as the Dispatcher.getInstance(). This may be an issue when for example your sender is in another web application. You may use the Pushlet protocol in that case or put pushlet.jar on the system CLASSPATH. In Tomcat you can also make pushlet.jar a shared library.

 

直接用Dispatcher的方法发布，可以向所有人广播，发布给订阅者，指定sessionid发布

1.2.2. Using EventSource

An EventSource is an object that is managed (activated/passivated) by the Pushlet framework. Developing your own EventSource involves creating a class that implements nl.justobjects.pushlet.core.EventSource (when your EventSource pushes Events to the framework) or that extends nl.justobjects.pushlet.core.EventPullSource (when the framework should pull your EventSource at dedicated intervals) and adding your EventSource to a properties file aptly namedsources.properties .

See /webapps/pushlet/WEB-INF/classes/sources.properties for an example. This file specifies which EventSource objects need to be created and managed. Note: since v2.0.3 sources.properties can also be placed under WEB-INF. See /src/nl/justobjects/pushlet/core/EventSourceManager.java how this is done. See examples in /src/nl/justobjects/pushlet/test/TestEventPullSources where several example sources are bundled.

During initialization the EventSourceManager will look for the file sources.properties in the CLASSPATH. Usually this file will be put under WEB-INF/classes.

一个自己写的事件源类，需要配置在sources.properties ，要继承EventPullSource 或实现EventSource

1.2.3. Using the Pushlet protocol

The Chat and WebPresentation examples use the remote publication of events through the Pushlet (control) protocol. In a webapp the Pushlet JS API provides a p_publish() method through which your app may send events.

The /src/nl/justobjects/pushlet/test/PushletPingApplication.java provides a complete example illustrating sending and receiving Events and using/src/nl/justobjects/pushlet/client/PushletClient.java . DHTML clients may use the JavaScript pushlet library.

 

使用pushlet 协议 收发交互   ，  可以跨服务器

评论

1 楼 pcgreat 2012-03-15  

    好文