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Event Listening and Event Bubbling
An Introduction with Examples in Java


Prof. David Bernstein
James Madison University

Computer Science Department
bernstdh@jmu.edu

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Event Queue
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  • Role:
    • Central repository for all events
  • Variants:
    • Event listening
    • Event bubbling
Using an Event Queue
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images/event-queue.gif
Variants
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Event Listening

images/event-listening.gif

Event Bubbling

images/event-bubbling.gif
Implementation: Event
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One Simple Implementation

javaexamples/eventbased/Event.java
 
Implementation: Event Queue
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javaexamples/eventbased/EventQueue.java (Fragment: skeleton)
 
javaexamples/eventbased/EventQueue.java (Fragment: fire)
 
javaexamples/eventbased/EventQueue.java (Fragment: run)
 
javaexamples/eventbased/EventQueue.java (Fragment: postEvent)
 
Event Listening
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Overview

images/event-listening_detailed.gif
Event Listenening (cont.)
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ListenerEvent

javaexamples/eventbased/ListenerEvent.java
 
Event Listenening (cont.)
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EventListener

javaexamples/eventbased/EventListener.java
 
Event Listenening (cont.)
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ListenerEventQueue

javaexamples/eventbased/ListenerEventQueue.java (Fragment: skeleton)
 
javaexamples/eventbased/ListenerEventQueue.java (Fragment: constructor)
 
javaexamples/eventbased/ListenerEventQueue.java (Fragment: addListener)
 
javaexamples/eventbased/ListenerEventQueue.java (Fragment: removeListener)
 
javaexamples/eventbased/ListenerEventQueue.java (Fragment: fireEvent)
 
javaexamples/eventbased/ListenerEventQueue.java (Fragment: singleton)
 
Event Bubbling
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Overview

images/event-bubbling_detailed.gif
Event Bubbling (cont.)
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BubblingEvent

javaexamples/eventbased/BubblingEvent.java
 
Event Bubbling (cont.)
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EventHandler

javaexamples/eventbased/EventHandler.java
 
Event Bubbling (cont.)
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An Abstract Event Handler that "Bubbles"

javaexamples/eventbased/AbstractEventHandler.java (Fragment: skeleton)
 
Event Bubbling (cont.)
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BubblingEventQueue

javaexamples/eventbased/BubblingEventQueue.java (Fragment: skeleton)
 
javaexamples/eventbased/BubblingEventQueue.java (Fragment: constructor)
 
javaexamples/eventbased/BubblingEventQueue.java (Fragment: setBubbleIfHandled)
 
javaexamples/eventbased/BubblingEventQueue.java (Fragment: fireEvent)
 
javaexamples/eventbased/BubblingEventQueue.java (Fragment: singleton)
 
Example: Event Listening
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images/event-listening_example.gif
Example: Event Listening (cont.)
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javaexamples/eventbased/SituationBoard.java
 
javaexamples/eventbased/MessageLogger.java
 
javaexamples/eventbased/MessageEntrySystem.java
 
javaexamples/eventbased/ListeningDriver.java
 
Example: Event Bubbling
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images/event-bubbling_example.gif
Example: Event Bubbling (cont.)
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javaexamples/eventbased/AbstractDocumentElement.java
 
javaexamples/eventbased/Word.java
 
javaexamples/eventbased/Paragraph.java
 
javaexamples/eventbased/Section.java
 
javaexamples/eventbased/BubblingDriver.java
 
There's Always More to Learn
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