Long Operations

Events for the same desktop are processed sequentially. In other words, an event handler will block any following handlers. Worse of all, the user, due to the limitation of HTTP, got no hint but the small processing dialog shown at the left-top corner on the browser.

With the echo event and the showBusy method as described in the Echo Events section above, you can provide a more descriptive message and prevent the user from, say, clicking other buttons to slow down the performance further for long operations.

However, blocking users from access might not be acceptable for your applications. To prevent the blocking, you have to, like desktop applications, process the long operation in another working thread. Then, report the processing status back the client continuously.

With ZK, you have four options: server push, suspend and resume, timer, and piggyback.