Java Magazine - July/August 2012

in the business layer and wrap the AsyncContext in a neutral wrapper. In the open source project LightFish, the class Browser Window is used to push GlassFish monitoring data to the JavaFX 2 client, as shown in Listing 6.

private AsyncContext asyncContext; private final ServletResponse response; private String channel;

JCA—If You Want More

Java EE Connector Architecture (JCA) 1. 6 connectors give you the most control over concurrency in a “legal,” convenient, and monitorable way. Furthermore, JCA connectors are managed by the application server, which usually gives you many configuration options. Building a JCA 1. 6 connector is not trivial, but it can be achieved in a few hours.

The implementation of the ResourceAdapter receives the BootstrapContext in the overridden start method, which gives you access to the WorkManager instance. You can safely ignore all other methods defined in the ResourceAdapter interface (see Listing 7).

You only need to compile the class shown in Listing 7, put it into a JAR file, change the .jar extension to .rar, and deploy the connector. The application server would create the WorkManagerBootstrap connector and pass the BootstrapContext with which the WorkManager instance can be obtained.

A WorkManager allows you to execute
javax.resource.spi.work. Work instances
that extend the Runnable interface. This
solution would work, but your applica-
tion would not be able to get a refer-
ence to the WorkManager without nasty
hacks. However, this implementation
would be sufficient to implement a
manageable network server.

public Browser Window(AsyncContext asyncContext) { this.asyncContext = asyncContext; this.response = this.asyncContext.getResponse(); this.response.setContentType("application/xml");

}

JAVA IN ACTION

public Browser Window(AsyncContext asyncContext,String channel){ this(asyncContext); this.channel = channel;

}
public void send(){
try{
}
public Writer get Writer(){
try {
return this.asyncContext.getResponse().get Writer();
} catch (IOException ex) {
throw new IllegalStateException("Cannot return writer: " + ex,ex);
}
}

this.asyncContext.complete(); }catch(Exception e){ }

ABOUT US

public void nothing ToSay(){ HttpServletResponse httpServletResponse = (HttpServletResponse) response; httpServletResponse.setStatus(204); this.asyncContext.complete();