Rectangle class to test for options...

What I am trying to do is write a class called Rectangle that maintains two attributes to represent the length and breadth of a rectangle. I've got to provide suitable get, set, and toString methods plus two methods that return the perimeter and area of the rectangle. Also, I must include two constructors for this class. One a parameterless constructor that initializes both the length and breadth to 0, and the second one that takes two parameters to initialize the length and breadth.  So far, this is what I have:


import java.io.*;

public class Rectangle
{
  protected long length;
  protected long width;
      
//....constructors go here

  public long get_length(){return length;}
  public long get_width(){return width;}
  public void set_length(long len){length = len;}
  public void set_width(long wid){width = wid;}
  public long area(){return width * length;}
  public long perimeter(){return 2 * (width + length);}
}

-----------------------------------------
//2 Constructors

public Rectangle()
   {
     length = 0;
     width = 0;
   }
      
  public Rectangle(long len, long wid)
   {
     length = len;
     width = wid;
   }
------------------------------------------
Then, after this, I've got to write a program (a driver application) that tests the above class by providing the users with the following menu options:
1 - to set the length
2 - to set the breadth
3 - to get the length
4 - to get the breadth
5 - to get the perimeter
6 - to get the area
7 - to print the object as string
0 - to quit
 
Eventually,  this program should create one Rectangle object at the beginning using the default constructor, and then repeatedly call the appropriate method for that object depending on the user selection from the above menu.

I'm not sure where to implement the code for this information or what I am missing.  Could you help me out please?  Thanks in advance!