How can I pass a Class as parameter and return a generic collection in Java?

Question

I am designing a simple Data Access Object for my Java application. I have a few classes (records) that represents a single row in tables like User and Fr

Answer 1

Well, I really don't know if you need it this way. But here is a polymorphic approach. It might help somewhere somehow.

Create different objects for different tables all implementing a common interface. This means you represent each table as an object.

import java.util.LinkedList;

public class DataAccessTest 
{

    /**
     * @param args
     */
    public static void main(String[] args) 
    {
        DataAccess myDataAccessObject = new DataAccess();
        Type type1 = new Fruit();
        Type type2 = new User();
        LinkedList list1 = myDataAccessObject.getAllRecords(type1);
        LinkedList list2 = myDataAccessObject.getAllRecords(type2);
        LinkedList list3 = myDataAccessObject.getAllRecords(new Fruit());
        LinkedList list4 = myDataAccessObject.getAllRecords(new User());
    }
}

class DataAccess
{
    public LinkedList getAllRecords(Type type)
    {
        return type.getAllRecords();
    }
}

interface Type
{
    public LinkedList getAllRecords();
}

class Fruit implements Type
{
    public LinkedList getAllRecords()
    {
        LinkedList list = new LinkedList();
        list.add(new Fruit());
        return list;
    }
}

class User implements Type
{
    public LinkedList getAllRecords() 
    {
        LinkedList list = new LinkedList();
        list.add(new User());
        return list;
    }
}