In concurrent object-oriented languages, customizable meta-objects are powerful
abstraction for extending and optimizing crucial implementation mechanisms such as
method dispatch and mutual exclusion. However, interpretive execution of meta-objects
causes severe performance penalty. Our previous study shows that applying partial evaluation
to meta-interpreters is useful for alleviating the problem, but partial evaluation
of existing meta-objects virtually fails, because they are concurrent objects and designed
as state-transition machines. This paper proposes a new meta-object design for our reflective
language ABCL/R3, which can be effectively optimized using partial evaulation.
The crux of the meta-object design is separation of state-related operations, which is
realized by using the reader/writer methods in our concurrent object-oriented language
Schematic. Our benchmarks showed that a non-trivial program with partially evaluated
meta-objects runs (1) 6.8 times faster than the one with merely compiled meta-objects,
and (2) only 2.2 times slower than the directly compiled program without meta-objects,
which is supposed to have the best performance. In addition, a program that uses a
customized meta-object for guarded method invocation runs as efficient as a directly
compiled program that implements the same functionality with application-level methods.