CS 4448 - Fall 1998
Object-Oriented Programming and Design
Homework #5

Due on Monday, October 5 at the start of class.

1. Hand in your HW#4 and the other persons HW#4 that you were given in class.
2. You must write comments on each design. Take into account that the design should have been totally unambiguous. This means that there are no places were you need to make design decisions. Everything missing should be coding details. You may make your comments on separate paper or on the HW#4 if you use a distinct ink color.
3. Make a new design. This may be your design or the other persons design from HW#4 for a hand full of you. Most of you will need to start over but may choose to use HW#4 as a starting point. The design must include amazing details including:
   • Inheritance hierarchy
   • The class that contains/has-a instance variable. So, if the variable living is found in MaterialObject then you need to show that in your design.
   • Show were methods are created. The method alive maybe found in the MaterialObject class. Describe what the method actual does in detail. So a constructor for dog needs to say what the passed in parameters do and what other things might be happening. Example, speak is being set to "Whof, Whoph".
   • The previous example with dog might also show where a method is overridden by a child. The old constructor, if it had the same parameters, was overwritten by the child. New functionality was added and then the parent was called. Your design should say what is happening and that the child does ... and then has the parent do its thing. You need to specify how the child calls the parents method but you don't need the parent detail in the child since the parent has that information. If you want to remove the some constructor or method that comes from the parent, an example is the constructor with no parameters. You can do this by having the child override that method and put it in private or in SmallTalk by having the child call the error: or shouldNotImplement method, etc....
   • Show has-a relationships, example: BeakerHolder has Beakers.
   • Show uses relationships, you find this one.
   You can decide how much detail to put in the diagram and put the rest in some other format on another page. Ex: class name then the list of methods and instance variable with the detail that you left out of your diagram.
4. Your may no longer hard code Mass into Molecule. You must find some way using Beaker, BeakerHolder, and Element to figure out the mass.
5. Make a new category in SmallTalk for you system. How about "HW#5"
6. Implement your design in SmallTalk.
7. Print out your SmallTalk code and hand it in.
8. Print out some tests showing what your system can do and hand it in.
9. Tar and then Gzip your work into one file. Make sure what you submit is correct. Email the code to yourself first. Make sure you get one file that you sent. Untar and ungzip the file. Now start Squeak and make sure it is not starting with your old state stored. File-in your assignment and try all your tests. If all goes well then...
10. Email your SmallTalk code to the TA. Remember it must be tarred and g-zipped. DO NOT send him more then one file, as it will not be accepted.

Requirements

Why fixed names?

This time the syntax I am using is SmallTalk.

Classes and class methods that need to work for instantiation

• Dog weight: name: kind:
• Cat weight: name: kind:
• Sprinter weight: name:
• Molecule name: 'Water' (Comment - The string Water is just one example)
• Beaker name: 'MagnesiumChloride' (Comment - Just an example name)
• Magnesium new
• Chlorine new
• Hydrogen new
• Krypton new
• Pine weight: height:
• Plant new
• Animal new
• BeakerHolder new (This class can be considered a stand that hold infinite Beakers)
• CouchPotato weight: name: (Comment - For those from different cultures, this is a person who watches TV all day and does not move unless they need a beer or to go to the bathroom)
• Student weight: name:

Periodic Table for your perusal.

Instances and minimum instance methods

• aDog speak; name; topSpeed; hasLiveYoung; spontaneousMovement
• aCat speak;legs
• aSprinter topSpeed;
• aStudent speak; legs
• aMolecule mass; name; chemicalSymbol
• aHydrogen mass; chemicalSymbol
• aKrypton name; family
• aPine deciduous;height
• aPlant alive
• aBeakerHolder find: ; hold: ; giveBack: (Comment: think of giveBack as unhold, add and remove might give you ideas of what hold: and giveback: do)
• anAnimal hasSex (Comment: this method is not a social commentary but a question about gender :)
• aBeaker numberOfAtoms; name; add: ; remove: (Comment: these methods let you add and remove atoms to the beaker)
• aCouchPotato speak; topSpeed; spontaneousMovement (Comment: See Animal vs. Plant in the dictionary. I agree see your question and I don't know the answer either. Is a CouchPotato Animal or Vegetable or Mineral, but certainly not the Model of a Modern Major General)