1. GridWorld Case Study Part 1 Experiments to Observe Attributes and Behavior of Actors A Summary by Jim Mims

2. Contents Introduction and Weighting Part 1: Observing and Experimenting with GridWorld Part 2: Bug Variations Part 3: GridWorld Classes and Interfaces Part 4: Classes that Extend the Critter Class Part 5: Grid Data Structures

3. Classes and Interfaces: Relationships

4. Introduction and Weighting The case study provides a graphical environment where visual objects inhabit and interact in a two-dimensional grid. Students design and creator actor objects, add them to a grid, and determine whether they behave according to specifications. Weighting Multiple-Choice Questions: Several Free Response Questions: 1

5. Observing and Experimenting with GridWorld The first demo contains a two-dimensional grid contaning two actors, a bug and a rock. Clicking on the step button runs one step, making each actor act once. Clicking on the run button caries out a series of steps until the Stop button is clicked. The delay between steps is controlled by the slider.

6. Observing and Experimenting with GridWorld Clicking on a empty cell displays a drop-down menu that shows the constructors for different actor types. The menu lists constructors for the classes of all objects that have ever been placed on the grid. Selecting one of the constructors places an instance of that type on the grid note the dialog box that appears for parameters.

7. Observing and Experimenting with GridWorld The dialog box mentioned on the previous slide is shown on the right. The grid uses directions as on a map, to include diagonal directions. One attribute of the bug is its direction (indicated by its antennae). Initially, the bug faces North.

8. Observing and Experimenting with GridWorld Clicking on an actor displays a drop-down menu of the methods that can be invoked on that actor. Those above the line are specified by the class that defines the actor. Those below the line are methods inherited from the Actor class.

9. Observing and Experimenting with GridWorld Accessor methods will have their results displayed in a dialog window. Modifier methods will cause an appropriate change in the display of the actor. If parameters are needed for a method, you provide them through a dialog window as shown on the right.

10. Observing and Experimenting with GridWorld Mouse ActionResult Click on empty locationShows constructor menu Click on occupied locationShows method menu Select Location-Delete menu itemRemoves the occupant in the currently selected location from he grid Click on the Step buttonCalls act of each actor Click on the Run buttonStarts run mode

11. Observing and Experimenting with GridWorld Mouse ActionResult Click on the Stop buttonStops run mode Adjust the Slow/Fast sliderChanges speed of run mode Select the Location Zoom in/Zoom outZooms grid display in or out Adjust the scroll bars next to gridScrolls to other parts of the grid (if grid is too large to fit in window)

12. Observing and Experimenting with GridWorld Mouse ActionResult Select the World Set grid menu itemChanges between bounded and unbounded grids Select the World Quit menu itemQuits GridWorld