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Part 1

The simulator should begin with three wash baskets on the screen (for our purposes they can just be rectangles or squares). One is labeled "whites", one "darks", and the last "colors". An image showing the kind of display we have in mind appears below.




When the simulation begins, a color swatch will appear on the screen. The user ("laundry trainee") should then click in the corresponding basket. If the user is correct, the program should randomly select a new color for the next item and display it on the screen. For this part of the assignment you may just select among the three colors Color.white, Color.red, and Color.black when creating items of clothing. If the user clicks on an incorrect basket, the original item remains in position for another try.

The image above will be a working version of the simple laundry sorter if your web browser supports Java 1.1. You should experiment with this demonstration version after you finish reading Part 1 to make sure you understand exactly what we have in mind.

A Warning!
One odd feature of the simple interface that may bother you a bit is a result of the fact that the program selects laundry items randomly. Because the selection is truly random it sometimes picks the same color twice in a row. When this happens and you click on the correct basket for the first item you will get the feeling that the program ignored you. Even though it has actually displayed a new item, the new item looks just like the old one, so you may think nothing changed. Don't let this trick you into thinking that your version of the program (or ours) isn't working correctly. The more advanced interface in Part 2 includes counters in the display that make it clearer whether the user succeeded.

Creating a Project

For this lab, you will create a project from scratch inside Eclipse:

  1. Open the File Menu. Select New and then Project.
  2. Select Java, then select Java Project, and then Next.
  3. Enter "Landry" as the Project name.
  4. Select the Libraries tab.
  5. Click Add variable.
  6. Select OBJECTDRAW from the list and click OK.
  7. Click Finish.
You now have an empty project to which you should add a Java file for your class:
  1. Click on "Laundry" in the Package Explorer panel on the left side of the Eclipse window.
  2. Open the File Menu. Select New and then Class.
  3. Enter "Laundry" as the Name of the class.
  4. Enter "WindowController" as the Superclass.
  5. Click Finish.
  6. You should now have a Laundry.java file inside the Laundry project. Be sure to modify the file so that it starts with import objectdraw.*; Later, when you start working the colors, you will also need to import java.awt.*.

Design of Part 1.

You will need to design an extension of the WindowController class which will display the wash baskets and the item to be sorted. Begin by laying out where all the items go on some graph paper. (We recommend using a window that has height and width of 400 pixels.) The picture should look more or less like the one above.

When the program begins, place all the wash baskets (with labels) on the screen. Then, add the item of clothing that is to be sorted. For simplicity you might as well always make the first item have color white. The item should actually consist of two rectangles, a FilledRect which is the appropriate color and a FramedRect which is the same size, but lays on top of the filled rectangle to form a border (otherwise it will be awfully difficult to see a white item!)

Think Constants!

When you lay out the wash baskets and item, define constants (private static final ...) for all the relevant information. This makes it easier to change the layout and also makes your program much, much easier to read (presuming you give constants good names). Constant names are by convention written with all capital letters and underscores, e.g. THIS_IS_A_CONSTANT. Your constants may be (and often should be) more complex objects like Locations. You can initialize constants with the results of a constructor:

      private static final Location SOME_LOCN = new Location(100,200);
Remember that you may NOT have constants whose definition uses canvas (e.g., no FramedRect constants).

The widths and heights of wash baskets and the item to be sorted, coordinates of the upper left corner of each of these, etc., are all good candidates for constants.

After writing the code to draw the initial display, it would be good to run it to see if it does what you expect. As with last week, you must create a configuration to run your program. These instructions are basically the same as last week, except that you will use a different name and different dimensions.

Identifying the Correct Basket

Once you have done the layout and figured out how to generate new items, all you have to do is to write the code for the method onMouseClick. Because you may be generating the item in one method (begin) and checking to see if the user clicked in the appropriate basket in a different method (the onMouseClick method), you will need to associate some information with an instance variable that will enable onMouseClick to determine which is the correct basket. An appropriate way to do this is to use an instance variable of type FramedRect.

When you generate a new item (in either begin or onMouseClick), you will associate the new variable with the rectangle/basket in which an item of its color should be placed. That way when the user clicks on a basket, onMouseClick can simply check to see if the rectangle currently associated with the instance variable contains the point where the mouse was clicked. Then, onMouseClick will either select a new color for the item (if the user was correct) or wait until the user clicks again (if incorrect).

Recycling
Because your program only uses one laundry item at a time, you might as well just recycle it - reusing the same rectangle for each laundry item. Simply change its color rather than creating a new rectangle. In general it is a good strategy to reuse objects rather than creating new ones when possible, as this generally uses less time and does not clutter memory.
Picking a random color
To pick a random color, use the RandomIntGenerator class as described in the textbook (Section 2.9). Since there are 3 colors to select from, you should create your random number generator to return random numbers in the range of 1 to 3 and associate each of those values with one of the colors the laundry may have (Color.white, Color.black, and Color.red).
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