Register Element

Group membership: Event-Handling

Registers an event handler for a specific event.

The specific events are specified using class and event. This identifies specific events that the JGB framework will listen for.

When an event is received at one of the ports, the JGB framework will turn around and call the the named method in the specified event manager.

JGB uses Java's Proxy services to provide the necessary framework. This is why the class reference must be an interface.

The methods that will be called in the event manager must follow the following conventions: they must be public, and return a void result. They must have two parameters: a java.util.EventObject, and a jgb.builder.WindowContext. In addition, the method must not throw an exception. JGB does not explicitely catch exceptions so they will propagate to the Swing environment, where they will be caught and logged to the console.

Attributes

Name	Type	Required	Description
class	CDATA	Yes	The interface that describes events that can be generated from this object. The fully qualified class name must be an interface, or the JGB framework will complain with an IllegalArgumentException wrapped in a SAXException. Additionnaly, the interface must not be in the default package. JGB will complain with a SAXException if that is the case.
event	CDATA	Yes	The name of an event upon which to act. This event must be a method declared in the interface named in class.
manager	IDREF	Yes	Determines which object should be notified of an event. This object must have been previously declared in the JGB XML description file.
method	CDATA	Yes	The method that should be called when an event is received. This method must have been declared on the object defined by manager.

Example usage

…

<!--
    Declare a java.awt.event.ActionListener that will listen for actionPerformed
    events and will call the method named "go" on the object saved in the
    context's eventManager object.

    The declared event manager implementation should look something like this:
    import java.util.EventObject;
    import jgb.builder.WindowContext;

    public class EventManager {
        public void go(EventObject event, WindowContext context) {
            // Implementation
        }
    }
-->
<object id="eventManager" class="jgb.examples.WebBrowserEventManager">
    <constructor/>
</object>

…

<textfield id="url" reflabel="urllabel">
    <register class="java.awt.event.ActionListener" event="actionPerformed" manager="eventManager" method="go"/>
</textfield>

…

Parent element(s)

button, check, combo, controls, control, item, label, menuBar, menu, object, panel, popupmenu, radio, separator, sheet, tab, textfield, window.

Child element(s)

None