//field declaration
boolean eventFired = false;

//Now in the event handler
if (!eventFired) {
    //set the field to true so this event handler will
    //return as soon as called afterwards
    eventFired = true;

    //do your processing...
    //change the text which will again fire this event
    //but since the value of the eventFired field will
    //be true, as soon as this event is fired the second 
    //time, it will return without doing anything

    //now after doing all processing needed, reset the
    //eventFired field, so future events are processed
    eventFired = false;
}