import java.util.*;

 interface Sortable {
/*
 *This interface models a protocol for things that can sorted relative to each other 
 */
 
 //Interface Sortable  Methods
 //============================
 
 public boolean canCompare(Sortable aSortable);
 //answer whether this Sortable and  aSortable can be compared
 //this method should answer true if the object this and aSortable are instances of the same class
 //This could be implemented as follows
 /*
    if(( this instanceof SomeClass ) && (aSortable instanceof SomeClass))
     return true;
   else {
   	 System.out.println("canCompare: ERROR: OBJECTS ARE NOT COMPARABLE");
   	 return false;
   }
 */

 
 public boolean comesBefore(Sortable aSortable);
 //answer whether this Sortable should come before aSortable in sorted order
 //this method should check that this and aSortable are can be compared and if not
 //an error message should be printed 
 
 public boolean comesAfter(Sortable aSortable);
 //answer whether this Sortable should come after aSortable in sorted order 
 //this method should check that this and aSortable are can be compared and if not
 //an error message should be printed 

 
}