guava - Java comparator by using priority for classes that extend a common parent class -

i need implement several comparators in java.

i have lot of known classes, a1, a2, a3, ..., an, extends class a. want to comparator class based on guava ordering, following:

ordering<a> sortertype1 = new ordering<a>() {         // here, provide set or similar keeps in memory         // class types , associated priority.           @override         public int compare(a left, right) {            // return -1 if class of left has higher priority wrt class of right;             // return  0 if class of left has same priority wrt class of right;             // return  1, otherwise.         } 

since need develop lot of different comparators, don't want put priority inside class type, since there several priorities differentiated each comparator. i'm missing parts comments.

what effective , efficient implementation of parts comments?

don't write compare implementation yourself, use ordering super powers (ordering#explicit(list) exact):

list<class<? extends a>> myorder = immutablelist.of(     a1.class, a4.class, a3.class, a2.class); ordering<a> explicitbyclassordering = ordering.explicit(myorder)     .onresultof(new function<a, class<? extends a>>() {       @override public class<? extends a> apply(a a) {         return a.getclass();       }     });  system.out.println(explicitbyclassordering.sortedcopy(     immutablelist.of(new a3(), new a2(), new a3(), new a1(), new a4()))); // [test$a1, test$a4, test$a3, test$a3, test$a2]