How to sort an vector of Object ?

[Engin Okucu]

I have some Objects in my Vector.
I want to sort it by using comparable interface.
It works fine when i sort by "username" but when i want to sort by "username" AND "lastname" AND "date" it doesn't work.
When it's more then 1 criterion i have problems to do it,
can you help me? thanks.

[Stan James]

I'm guessing the objects in your vector are really some type that you made up with those fields. Going from there ... your comparator probably looks like:

compare(Object one, Object two)
{
   MyClass myOne = (MyClass)one;
   MyClass myTwo = (MyClass)two;
   return myOne.field.compareTo(myTwo.field);
}

Is that close? It needs some checks for nulls, instance of and such at the beginning to be very safe.

So now you want to sort by two or three fields. I do something like this:

   int result = myOne.field1.compareTo(myTwo.field1);
   if (result == 0) result = myOne.field2.compareTo(myTwo.field2);
   if (result == 0) result = myTwo.field3.compareTo(myOne.field3);
   return result;

Does that make sense? If the 1st field doesn't match I'm done. But if it does match I check the 2nd field. And if those match I check the 3rd field.

Note that I reversed myTwo and myOne in the 3rd test to sort descending order on that field. Does that look useful?
[ December 07, 2004: Message edited by: Stan James ]

[Engin Okucu]

Hi Stan,

I would like to thank you very much. Now it works fine.