net.java.html.json

Annotation Type OnPropertyChange

@Retention(value=SOURCE)
 @Target(value=METHOD)
public @interface OnPropertyChange

Marks a method that is going to be notified when a property defined by Model has been changed. This is especially useful when one wants to react to changes in the model caused by the rendered view. In case of knockout.js technology one could for example react to selection of a name from a combo box:

 
 <!-- associates the selected value with property name -->
 
 <select data-bind="value: name">
   <option>Jiří</option>
   <option>Jarda</option>
   <option>Petr</option>
   <option>Tomáš</option>
 </select>
 
 // Java code snippet reacting to change of the name property:
 
 @OnPropertyChange("name") 
 static void propertyChanged(AModel inst, String propertyName) {
   // schedule some operation
   // on the model
 }
 

The method's first argument should be the instance of the associated model class. The method shall be non-private and unless instance mode is on also static. There can be an optional second String argument which will be set to the name of the changed property. The second argument is only useful when a single method reacts to changes in multiple properties.

An online example using this technique is available here - it observes selection in a combo box and in case it changes the example sends a network request and asynchronously updates list of code snippets.

Author:

Jaroslav Tulach

Required Element Summary

Required Elements

Modifier and Type	Required Element and Description
String[]	value Name(s) of the properties.

Element Detail

value

public abstract String[] value

Name(s) of the properties. One wishes to observe.

Returns:

valid java identifier