Comparare due oggetti

[tv9vision]

Ciao a tutti,
qualcuno sa dirmi dove sbaglio?

  private void insertSorted( Object i ) {
      if ( first == null ) {
         // initial list is empty
         first = new ObjectListElem( i, null );
      } else {
         // initial list has at least one element
         if ( compare(i,first.value) < 0 ) {
            // add as first
            addFirst( i );
         } else {
            // add someplace after the first
            ObjectListElem elem = first;
            while ( elem.next != null ) {
               if ( compare(i,elem.next.value) < 0 ) {
                  // insert between e and e.next
                  elem.next = new ObjectListElem( i, elem.next );
                  return;
               }
               elem = elem.next;
            } // end while()
            // end of list reached and not yet inserted: add last
            addLast( i );
         }
      }
   } // end insertSorted()
} // end class ObjectList

L'errore che mi da il compilatore è

docking-hg-48-181-dhcp:~/Desktop matteo$ javac ObjectList.java
ObjectList.java:211: cannot find symbol
symbol  : method compare(java.lang.Object,java.lang.Object)
location: class ObjectList
         if ( compare(i,first.value) < 0 ) {
              ^
ObjectList.java:218: cannot find symbol
symbol  : method compare(java.lang.Object,java.lang.Object)
location: class ObjectList
               if ( compare(i,elem.next.value) < 0 ) {
                    ^
2 errors

Grazie

[pozzad]

Devi implementare il metodo "compare" per poterlo usare....

ciao