A06

Due Date: Friday, 5 March 2021
File(s) to be submitted: FigureInfo.java, Measurable.java, Circle.java, Oval.java, Rectangle.java, Triangle.java
Sample Output: SampleOutput.html
Starter Files:

• FigureInfo.java
• Measurable.java
• Circle.java
• Oval.java
• Rectangle.java
• Triangle.java

Figure Info (Interfaces and Polymorphism)

Summary

Revise the Measurable interface so that it extends Comparable<Measurable>.

Note that once you make this change, the Shape classes will all have errors in them -- they don't implement the compareTo(Measurable) method. The implements Measurable clause now includes a promise to implement that method.

Revise the shape classes so that they actually implement the compareTo(Measurable) method.

Note that by making Measurable extend Comparable<Measurable>, the promise to be Measurable implies a promise to be Comparable<Measurable>, so you don't need to promise that again.

Also, you shouldn't change the shape classes from implementing Measurable.

Revise the program FigureInfo so that it reads in three objects of each shape, storing all twelve of the shapes in a single array, then sorts that array and prints it out in a nice table. (Right now it reads in a single instance of each shape and prints out those four shapes in a table -- not sorted.)

Details

There's not much more to say than I said above.

• Do the revisions in the order I mentioned them above.
• The revision to Measurable is very small.
• The revisions to the shape classes are smallish -- and all the same. When we sort the Measurable shapes, we want them sorted by area, from smallest to largest.

  Note 1: The version of Rectangle in the sample programs is sorted by width and then height. Your version will be similar, but not the same.

  Note 2: There's an even better way to do this task when all the implementing classes do things the same way, but that'd take us into abstract classes, which are a bit more advanced than I want to get into. DO NOT use abstract classes for this assignment.

• Recompile FigureInfo after the above revisions are done. It should still behave exactly as it did before!
• The required revisions for FigureInfo are all marked with TODO comments.
  • Remember to recompile regularly as you do your revisions. Your program should usually compile after each TODO is completed (tho you may need to comment out the lines that print the table when you start working on the loops).
  • The program reads multiple shapes into an array, and you'll need to use four loops to do the reading (one for each kind of shape). Be careful when you save the shape into the array that you don't erase the earlier shapes (by, for example, looping i from 0 to FIGS_PER_SHAPE and then saving into the [i] element of the array). You should instead create and use a variable to keep track of how many shapes have been entered into the array, and save into that position of the array.
• Finally, you can test your program by running it and typing in all the data required -- but that might be rather slow. Instead, you can copy the following data and paste it as the input to the program:
  30 40 10 20 50 60 10 20 50 50 30 40 20 50 10 30 30 40 50 700 20