Using classes to store information

Question

I am writing a program that reads a text file and parses the data. I have the reading part done but I am not sure how to handle the parsing.
The text file contains something like this:
Session #1342
Subject #143 selected Object 5
Subject #144 selected Object 3
Subject #146 selected Object 2
Subject #147 selected Object 2
Session #1354
Subject #143 selected Object 1
Subject #144 selected Object 3
Subject #146 selected Object 1
Subject #147 selected Object 9
This program will process different text files that will have different sessions and different Subjects.
I have the code done that determines if the line is contains session information or subject information. I want to keep track of how many times each subject selects a specific object. This data will be display once the text file is processed.
The first session in the file will tell me which subjects are included in the text file. I thought I could create a class that would be used for each subject. So when the program first looked at:
Subject #143 selected Object 5
the code would create a class for this subject.
Subject subject_A = new Subject(143);  // The 143 is parsed from the text fileThen I could use a method to increase the Object 5 count by one. Like:
subject_A.add_Object5();I am not sure how I can identify that subject_A is for my subject#143 the next time it comes up in the text file.
I need a dynamic way to create the Subject class. The number of subjects in the text file can vary. And the order they appear in each session is varied.
I solution would be to code a set number of new classes like:
Subject subject_A = new Subject(); 
Subject subject_B = new Subject(); 
Subject subject_C = new Subject();  Then have program logic that starts with subject_A, check if it has a been assigned, if not it assigns a subject to it or it moves to subject_B.
Then when the next session is read, I would loop thru all the classes checking if subject_A is number 143, then increase the counter in that class.
This seems like a very long and wrong way to do it.
Is there any better way to do this?

Answer 1

As for the parsing, you could handle it a couple of ways:
If you always have the same format then an indexOf("#") from the String class would return the postion of the # sign, just add to the value to move into the string, and use substring to copy out value, also from the String class. - or -
Use the token feature of Java and let it tokenize the string, search forum for code samples, already posted.
As to the storage, maybe a simple Vector, or Set, if need to be unique. Use the == to check for object equality rather than .equals().