Re: Comparator in the driver

thufir wrote:
>     79          static final Comparator<Guest> BY_NAME = new 
> Comparator<Guest>(){
>     80                  public int compare(Guest g1, Guest g2){
>     81                          ContactInfo c1 = g1.getContactInfo();

What if g1 or g2 are null?

>     82                          ContactInfo c2 = g2.getContactInfo();
>     83                         
System.out.println("******************");

Don't put output in a Comparator.

>     84                          String s1 = c1.getLastName();
>     85                          String s2 = c2.getLastName();

What if c1 or c2 are null?

If the design of ContactInfo guarantees non-null elements, use 'assert' to

assure the invariants.

>     86                          int foo = s1.compareTo(s2);
>     87                          System.out.println(foo);

Really, don't put output in Comparators.  Also, "System.out.println()" may
be 
ugly and inflexible, but at least it causes lots of unnecessary overhead
in 
production without providing any benefit as used here.

>     88                          return foo;
>     89                  }
>     90          };

> I'd like to put this Comparator into a00720398.util.CollectionUtil and 

That's an interesting package name.

> still keep the collections in the driver to meet other requirements.
> 
> Any pointers as to how to do that?

Just declare a top-level class in that package.

package a00720398.util;

public class GuestComparer implements Comparator <Guest>
{
  @[EMAIL PROTECTED]
  public int compare( Guest g1, Guest g2 )
  {
   if ( g1 == null )
   {
     return (g2 == null? 0 : -1);
   }
   if ( g2 == null )
   {
     return 1;
   }
   ContactInfo
     c1 = g1.getContactInfo(),
     c2 = g2.getContactInfo();
   return (c1 == null? (c2 == null? 0 : -1)
            : c1.compareTo( c2 ));
  }
}

If you want to make it a nested class (why in the world would one do
that?), 
that's easy enough to do.

-- 
Lew