WebLogic Events

The BigTel engineers knew from the beginning they'd need realtime information. "WebLogic Server has a built-in event service that makes this easy," the Java engineer said. "We built a small browser applet that you'll see in action in the interactive tour. We've captured a screen shot here to illustrate how it works. This bar graph shows the number and priority of all open calls at any moment. Here it shows the current open calls. The bar graph changes to indicate not only number of calls, but also gives you a visual idea of the proportion of critical, high, medium, and low priority calls."

"The bar graph changes immediately whenever a current call status changes or a new call is entered, by any field engineer currently logged into the BigTel App. That's all done with events. When any field engineer opens a new call or changes the priority of an existing call, the problem table is updated, and simultaneously all the applications that have registered an interest in problem-table data are informed of the change."

Bar graph applet

"As clients update the problem table, all the changes get sent to all interested parties -- everyone who has registered interest in changes in the data automatically gets realtime updates. And all that transfer of information is done only when there are changes -- no client ever polls, or camps on the wire waiting for a potential change."

"Is this what everyone's been talking about -- server-side push?" Mr. Imayess asked. "Is there really anything to all the hype?"

"A lot of the hype is just that -- some people who advertise push really just use very smart pull," the Java engineer nodded. "But WebLogic Events are true server-side push. The client never asks the server for an update. The server automatically updates the client as soon as the event happens. It's efficient with network resources, and the events themselves are light enough so the server can handle thousands of them a second. It's very cool."

"So what about business rules for making sure we service our various levels of contracts at the right priority?" asked Mr. Imayess.

"Glad you asked! Take a look at this," the Java engineer said.

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