wise0 memo.txt

Ethan Bolker
May 5, 2004

This project falls naturally into two parts: the various lists (like
the Bank's BankAccounts or Juno's JFiles) and the command loop to send
messages to the objects on those lists (like the Bank's manager and
customer commands, or Juno's ShellCommands). You can write either half
first. I chose to do the list and object part first.

There are Maps for Course, Student and Professor objects. Since each
of these objects is put into a Map using a String name as a key, I
made them extend WISEObject and put the name there.  All the fields
are private. I will add getters as I need them.

The three lists are in instances of CourseList, StudentList and
ProfessorList, each extending WISEList, using the code from the
second exam as a starting point. 

main in class WISE asks the list constructors to read the three input
files. By putting the code that opens the files and reads the lines
into the WISEList constructor I didn't have to duplicate it.

Then main prints the contents of the three lists (just as the WISE
type command will print them some day) to prove that they have been
read correctly. toString methods in all the classes make this pretty
easy.

I have just begun to get ready to tie the lists together. A Student
object has a List (or maybe a Map) of Courses she is enrolled in, and
an add(Course) method to do the job. Of course that's just a stub now,
but it does compile.

Similarly, a Professor has an add(Course) method, and a Course has
both add(Student) and add(Professor) methods. When I enroll a Student
in a Course I will send add messages to each one using the other as an
argument. I will do the same kind of thing when I assign a Professor
to a Course.

(One problem that I haven't thought about yet is how I will find a
Student when I know her ID but not her name, since the list has the
Student name as a key. If I run out of time I will just not do
that. It's more important to get enroll and assign working first.)

I haven't yet decided whether the WISE command loop will be easier to
write with a dispatch table like Juno's, or with if/else as in the
Bank. Whichever way I do it, it's pretty clear that "type courses" and
"type students" and "type professors" are essentially done.

There's no error checking for the input files (we were promised they
would be correct) but I will need it when I work with what the user
types at the prompt. I have the WISEException class ready for that.

Finally, I wrote a TimeOfDay class whose instances are created with
two Strings, one for the "MWF" part and the other for the hour part. I
put an equals method in that class to decide when two TimeOfDay
objects really represented the same time, and I wrote a unit test to
see that it worked. This will be useful when I need to decide whether
a student or a professor has a time conflict. There's also a stub
there to ask whether a TimeOfDay object is a legal time for a course.