Implementing a Component Property

A property usually has a getter and a setter. The getter is straightforward:

private String _value = ""; //a data member
 
public String getValue() {
 return _value;
}

The setter is similar except we have to notify the client. This is achieved by using the org.zkoss.zk.ui.AbstractComponent#smartUpdate(java.lang.String, java.lang.Object) function.

public void setValue(String value) {
 if (!_value.equals(value)) {
  _value = value;
  smartUpdate("value", _value);
 }
}

The org.zkoss.zk.ui.AbstractComponent#smartUpdate(java.lang.String, java.lang.Object) function causes ZK Client Engine to call the setValue method of the peer widget (the first argument is the property name). Then, the widget can manipulate the DOM tree from there.