Bug 316148

Description Stephan Herrmann 2010-06-08 10:52:08 EDT

OTJLD §4.8(d) currently reads:
" Multiple precedence statements

  All precedence statements are collected at the outer-most team. At that level
  all precedence declarations involving the same base method are merged using
  the C3 algorithm [3]. It is an error to declare incompatible precedence lists 
  that cannot be merged by the C3 algorithm."

While this ensures that the actual precedence will _conform_ to all individual
precedence declarations, this fails to determine the actual ordering
when class-based and binding-based precedence declarations need merging.

Consider this team:

public team class MyTeam {
  precedence MyRoleB.bl1, MyRoleA;
    protected class MyRoleB playedBy MyBase {
      precedence bl1, bl2;
      void rm() {
        System.out.println("RoleB.bl1");
      }
                
      bl1: rm <- before bm;
                
      void rm2() {
        System.out.println("RoleB.bl2");
      }
      bl2: rm2 <- before bm;
    }

    protected class MyRoleA playedBy MyBase {
      void rm() {
        System.out.println("RoleA");
      }
      rm <- before bm;
    }
}

calling bm() currently produces:

RoleB.bl1
RoleA
RoleB.bl2

whereas the following would be legal too:

RoleB.bl1
RoleB.bl2
RoleA

Actually, the latter seems more intuitive because it gives priority
to inner precedence declarations ("bl1, bl2") over outer precedence
declarations ("MyRoleB.bl1, MyRoleA").

The OTJLD should be updated to disambiguate the behavior and the 
implementation be adjusted accordingly.