Working with the Framework - Effective C# - page 189

return left.CompareTo(right) >= 0 ;
}
private static RevenueComparer revComp = null ;
// return an object that implements IComparer
// use lazy evaluation to create just one.
public static IComparer < Customer > RevenueCompare
{
get
{
if (revComp == null )
revComp = new RevenueComparer ();
return revComp;
}
}
public static Comparison < Customer > CompareByReview
{
get
{
return (left,right) =>
left.revenue.CompareTo(right.revenue);
}
}
// Class to compare customers by revenue.
// This is always used via the interface pointer,
// so only provide the interface override.
private class RevenueComparer : IComparer < Customer >
{
#region IComparer<Customer> Members
int IComparer < Customer >.Compare( Customer left,
Customer right)
{
return left.revenue.CompareTo(
right.revenue);
}
#endregion
}
}