用Java存储对象集合的最佳方法？

Question

I am creating a dump Java app for student information system for learning and implementing OOPS Concepts like inheritance, abstraction, polymorphism and encapsulation.

What I am doing is, I have created Faculty Class, Student Class and a College Class. Now i want to add new faculty in College. So my approach is to create a method in College class ie addFaculty(Faculty f) and fireFaculty(Faculty f) , now i want to add Faculties in College class.

Whats the best way to do it? How do i store list of Faculty Object in College Object. Because i can add more than one faculty and more than one student in college.

Whats the best approach to solve this problem in OOPS?

Here is College.java code which i have implemented, it works fine but is this the best way i can solve it?

public class College 
{
String name;
String location;
String courses[];
HashMap<String,Faculty> faculties;
int noOfFaculties = 0;
int noOfStudents = 0;

public College(String name,String location,String courses[])
{
    this.name = name;
    this.location = location;
    this.courses = courses;
    faculties = new HashMap<>();
}

public void addFaculty(Faculty faculty)
{
    faculties.put(faculty.getName(),faculty);
}

public void printFaculties()
{
    Set<String> set = faculties.keySet();
    if(set.size()>0)
    {
        for(String s:set)
        {
            System.out.println(faculties.get(s).getName());
        }
    }
    else
    {
        System.out.println("No Faculties Currently Working");
    }
}

public void fireFaculty(Faculty faculty)
{
    faculties.remove(faculty.getName());
}
public String getName()
{
    return name;
}

public String getLocation()
{
    return location;
}

public String[] getCourses()
{
    return courses;
}
}

Answer 1

There's a ton of ways you can do it. Probably the easiest way to handle storing a collection of objects is by using one of the Collections provided by Java. For beginners, probably the easiest one to understand is an ArrayList , which is basically an array that grows in size dynamically depending on the amount of objects in the collection.

So, as an axample, your code might be something like this:

public class College
{
    private ArrayList<Faculty> faculty;

    public College()
    {
        faculty = new ArrayList<Faculty>();
    }

    public void addFaculty(Faculty f)
    {
        faculty.add(f);
    }

    public void fireFaculty(Faculty f)
    {
        faculty.remove(f);
    }
}

Answer 2

If you cannot have duplicates use HashSet<Faculty> if you dont mind use a List<Faculty> .

Example:

class College {
    private List<Faculty> listFactories = new ArrayList<>();  // dupes allowed
    private Set<Faculty> setFactories = new HashSet<>(); // no dupes allowed
}

Check collections API .

Answer 3

imho It depends what kind of services College college offers. If I were coding, I would start with:-

List<Faculy> faculties = new ArrayList<>();
....
public void addFaculty(Faculty f) {
  faculties.add(f);
 }
 //... etc 

And change to an altearnative later if needed.