Please help with Collection

Question

Hello, I have an assignment on collection and have tried to implement it but facing errors that i am unable to understand.
Below is what i am supposed to do and below that is my code which is ofcourse not working as always (just kidding)
Question:
Design and Implement a class called SimpleEmailManager, in package swd.util, which manages a collection of SimpleEmail instances. The manager�s behaviour is shown in the following sample codes:                         [35%]
SimpleEmailManager manager = new SimpleEmailManager();
// Construct a SimpleManager that manages an empty collection of SimpleEmails
SimpleEmail m1 = new SimpleEmail (�);
Mail m2 = new Mail (�);
m1.setCreateDate(new java.util.Date(�Jan 1, 2002�));
m2.setCreateDate(new java.util.Date(�June 16, 1997�));
manager.add(m1); // Add Mail m1 to the collection
manager.add(m2); // Add Mail m2 to the collection
SimpleEmail m = manager.getNewestMail();
// Return one of the SimpleEmail in the collection with the most recent creation
// date. Return null if the collection is empty
java.util.Iterator iterator1 = manager.getMailMadeBefore("Jan 1, 1998");
// Return an Iterator of the Simple Mails in the collection created Before
// the specific date
java.util.Iterator iterator2 = manager.iterator()
// Return an Iterator of the collection managed by the manager
manager.remove(m1)
// Remove mail m1 from the collection
My Solution:
package swd.util;
import java.util.*;
import javax.swing.*;
import swd.util.SimpleEmail;
import swd.util.Mail;
* <p>Title: SimpleEmailMsnsger Class</p>
* <p>Description: Manages a colection of objects of simple email class</p>
* <p>Copyright: Copyright (c) 2003</p>
* <p>Company: </p>
* <p>author Irfan Noor Bukhari ID=12748237</p>
* <p>version 1.0</p>
public class SimpleEmailManager
     SimpleEmailManager manager = new Collection();
     public SimpleEmailManager()
          SimpleEmail m1 = new SimpleEmail ("Wag The Dog", "[email protected]", "[email protected]");
          Mail m2 = new Mail ("[email protected]", "[email protected]", "Is this the subject", "Wag The Dog");
          m1.setCreateDate(new Date("Jan 1, 2002"));
          m2.setCreateDate(new Date("June 16, 1997"));
          manager.add(m1);
          manager.add(m2);
          SimpleEmail m = manager.getNewestMail();
          //JOptionPane.showInputDialog("Enter Date")
//          Collection c;
//          c.add(m1);
//          c.add(m2);
//m1.setCreateDate(new java.util.Date("Jan 1, 2002"));
//m2.setCreateDate(new java.util.Date("June 16, 1997"));
//manager.add(m1); // Add Mail m1 to the collection
//manager.add(m2); // Add Mail m2 to the collection
//SimpleEmail m = manager.getNewestMail();
// Return one of the SimpleEmail in the collection with the most recent creation
// date. Return null if the collection is empty
//java.util.Iterator iterator1 = manager.getMailMadeBefore("Jan 1, 1998");
// Return an Iterator of the Simple Mails in the collection created Before
// the specific date
//java.util.Iterator iterator2 = manager.iterator()
// Return an Iterator of the collection managed by the manager
//manager.remove(m1)
//     public Collection add(SimpleEmail o)
//          Collection c;
//          c.add(o);
//          return c;
     public SimpleEmailManager getNewestMail()
          Iterator i = manager.iterator();
          if (manager == null)
               return null;
          else
               while ( i.hasNext() )
                    System.out.println(i.next().toString());
          return     i.next();
     public static void main(String[] args)
          new SimpleEmailManager();
please help me

Answer 1

How much of java do you know? Since you have started working on Collections I take it that you have covered the basics of class, constructors, variables & their types & such like. From your code it is apparent that you still haven't understood these basic concepts. I'd recommend that you read your notes, read a good book on java, read the tutorials on sun's website (the 1st few trails), get a firm grasp of these basic concepts first and then go back to your Collections assignment. Yes, this is a lot of work; yes it will take time; but nothing of value can be learned without expending time & energy.
Since I'm feeling rather magnanimous at this time, I'll give you a hint. You have class called SimpleEmailManager; you are declaring a variable called manager of type SimpleEmailManager in the constructor; but you are trying to create it as a Collection type. Decide whether the var manager is SimpleEmailManager or Collection.