Adds the listener to the collection of listeners who will
be notified when an event of the given type occurs. The event
type is one of the event constants defined in class <code>SWT</code>.
When the event does occur in the display, the listener is notified by
sending it the <code>handleEvent()</code> message.
@param eventType the type of event to listen for
@param listener the listener which should be notified when the event occurs
@exception IllegalArgumentException <ul>
<li>ERROR_NULL_ARGUMENT - if the listener is null</li>
</ul>
@exception SWTException <ul>
<li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
<li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
</ul>
Adds the listener to the collection of listeners who will be notified when an event of the given type occurs. The event type is one of the event constants defined in class <code>SWT</code>. When the event does occur in the display, the listener is notified by sending it the <code>handleEvent()</code> message.
@param eventType the type of event to listen for @param listener the listener which should be notified when the event occurs
@exception IllegalArgumentException <ul> <li>ERROR_NULL_ARGUMENT - if the listener is null</li> </ul> @exception SWTException <ul> <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li> </ul>
@see Listener @see SWT @see #removeListener
@since 2.0