ZK Developer's Guide

Getting Started with ZK
Event Processing Thread—Initialize and Cleanup
One important thread in a ZK application is the event processing thread. In this
thread an event listener is processed.
Sometimes there is a demand to initialize or clean up the thread. For this we have
the org.zkoss.zk.ui.event.EventThreadInit-interface. This interface has the
method init(Component, Event) which must be implemented (and the prepare
method). To register the listener it's necessary to make an entry in WEB-INF/zk.xml.
sample.SampleEventThreadInit
stener>
For cleanup there is the org.zkoss.zk.ui.event.EventThreadCleanup interface.
Here, we have to implement the cleanup(Component, Event, List)method;
additionally we also have to implement the complete method. The last parameter for
the method cleanup is a list of exceptions that occur before the method is executed.
To register the listener it's necessary to make an entry in WEB-INF/zk.xml.
sample.SampleEventThreadCleanup
An example implementation of such a listener is shown in Appendix A.
Until now we have used ZUML, but we haven't really explained what ZUML is
and how to use it. The next section should you give some idea about working with
ZUML. Before we start, it's important to note that the next section is not a reference
for ZUML, it's just a guide to help in the development of a ZUML page.
Event Types
The following event types exist in ZK:
•
•
•
•
•
•
Mouse Events (e.g. onClick)
Keystroke Events (e.g. onOK)
Input Events (e.g. onChange)
List and Tree Events (e.g. onSelect)
Slider and Scroll Events (e.g. onScroll)
Other Events (e.g. onZIndex)
[ 28 ]