COMP 504 Fall 2015	Composition-based Ballworld Demo with Multiple Switchers

The demo should appear on your screen in its own window. To restart the demo, refresh/reload this page.

Note:  it is an Honor Code violation to attempt to decompile any supplied code

There is a web page that explains how this demo makes multiple switcher balls that is only available via a link in your particular class's Owlspace Rsources site.

• Type the name of a strategy into the text field on the left.  See the list below for the available strategies.  Clicking the "Add to Lists" button will then add it to both the drop lists.
• "Make Selected Ball" will make a ball with the strategy selected on the top drop list.
• "Combine!" will dynamically create a strategy that is the combination of the strategies selected on top and bottom lists. The new strategy is placed back into both drop lists and can be used again for combining. For instance, add then combine "Curve" and "Breathing" to make a ball that curves and breathes.
• "Add Switcher" will add a factory for a switcher ball to the drop list.   The name of the new switcher strategy will be "Switch N" where N is an integer starting at 1.  Initially, unless switched to a new strategy, the balls made with the new switcher strategy factory will behave as the selected strategy on the top drop list when the "Add Switcher" button was clicked.     This process will also create a matching "Switch N" button on the GUI that will switch the behavior of all switcher strategies made with the "Switch N" strategy factory. 
• Clicking one of the "Switch N" buttons will cause all balls made with switcher strategies associated with that button to switch behaviors to whatever is the selected strategy on the top drop list. Switcher balls made later using the same switcher strategy factory will have the same behavior as whatever the previously made Switchers from that factory have.

If you hold the mouse over any button, a tooltip will pop up that will tell you what that button does.

The following different types of strategies are available for use, plus any switcher strategies created:

• Straight
• Curve
• Color
• Breathing
• Wander
• Drunken
• Change1
• Change2

Try combining switcher strategies and see what happens!

Important Design Notes

This code has the following design features:

• Does NOT CONTAIN AN ARRAY of switcher strategies anywhere.
  • No references to the created switcher strategies are maintained within the model.
  • No structure or process exists anywhere in the system that manages the created switcher strategies (other than objects that hold them individually).
•  NO BALL REFERENCES are maintained, other than internally by the dispatcher.
  • There are NO ITERATIONS OVER THE BALLS for any purpose (other than perhaps internally to the dispatcher).  
  • There is NO PER-BALL MANAGEMENT anywhere.
• Does not couple the view to the model in any manner.  
  • There are NO COMMON INTERFACES OR CLASSES to both the model and the view.
  • The view has no notion of strategies, factories, switchers, etc.  
  • The model has no notions about buttons, drop lists, action listeners, etc.
• There is NO named switcher strategy class anywhere in the system.
• There is NO named composite strategy class anywhere in the system.
•  The "Switch N" buttons are created and connected at run-time when the "Add Switcher" button is clicked.
  • Essentially a "mini-MVC" is dynamically created for every switcher.
• Execution loops, e.g.  a switcher is asked to switch to itself, are detected and behavior is reduced to a no-op (straight ball) in those situations.   An error message is printed out to the Java Console. 

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© 2015 by Stephen Wong