Issue 1619:  Abstract Interfaces issue (java2idl-rtf)
Source:  (, )
Nature:  Revision
Severity: 
Summary: Summary: The current Java to IDL mapping spec does not fully address support
 for abstract interfaces.  There is support for these in the
 Portability Interfaces chapter, but not in the RMI/IDL Subset or
 IDL Mapping chapters. 
 

Resolution: 
Revised Text: 
Actions taken:
June 30, 1998: received issue
February 24, 1999: closed issue
Discussion: 

End of Annotations:=====
Return-Path: <nash@sp3at21.hursley.ibm.com>
Date: Tue, 30 Jun 1998 11:24:01 +0100
From: Simon Nash <nash@hursley.ibm.com>
Reply-To: nash@hursley.ibm.com
Organization: IBM
To: java2idl-rtf@omg.org
Cc: issues@omg.org
Subject: Abstract Interfaces

The current Java to IDL mapping spec does not fully address support
for abstract interfaces.  There is support for these in the
Portability Interfaces chapter, but not in the RMI/IDL Subset or
IDL Mapping chapters. 

The reason the support was omitted from these chapters was that 
Java RMI does not support abstract interfaces in JDK 1.1, and it
was a goal of the submission to make RMI/IDL a strict subset of
current Java RMI.  However, given the forthcoming release of
JDK 1.2, which does contain support for abstract interfaces, it
is appropriate to reconsider this.

We are working on an implementation of the mappings for both
JDK 1.1 and JDK 1.2.  It is important that we have a specification
of how support is to be provided for abstract interfaces so that we
can add it to our 1.2 implementation.

Whether or not abstract interfaces are supported is purely a 
compile-time issue.  No extra support is needed in the runtime.
It is therefore possible, with a suitably enabled compiler, to
support abstract interfaces on JDK 1.1 for both JRMP and IIOP.
For IIOP, Java RMI abstract interfaces are mapped to IDL abstract
interfaces (part of the OBV spec).

Given all this, I propose extending the Java to IDL mappings to 
support abstract interfaces by making the following changes to 
the orbos/98-04-03 spec:

1. In section 4.3 on page 24, remove numbered item 3.
2. In section 4.3 on page 24, in numbered item 4, change "in the
   interface" to "in the interface (including inherited methods)".
3. In section 4.4 on page 25, remove footnote 1 from numbered
   item 5.
4. In section 5.8 on page 42, first para after the bullets, 
   change "IDL value type" to "IDL type".
5. In section 5.8 on page 42, replace last para by:
     Non-conforming Java classes are mapped to concrete IDL value 
     types with no data members.  Non-conforming Java interfaces 
     are mapped to IDL abstract interface types if all their method
     definitions throw java.rmi.RemoteException, and to IDL abstract
     value types otherwise.
6. In section 5.8.3 on page 42, change "inherited value type" to
   "inherited type".
7. In section 5.8.4 on page 42, replace existing text by:
     For non-conforming Java interfaces that are mapped to IDL 
     abstract interface types, methods and constants are mapped 
     according to the rules specified in sections 5.4.4 and 5.4.5.
     For non-conforming Java classes and interfaces that are mapped
     to IDL value types, we do not specify a mapping for methods
     and constants.
8. In section 5.8.5 on page 43, add a Java type:
     public interface Bear {
         public int getSize() throws RemoteException;
     }
   and an IDL type:
     abstract interface Bear {
         long getSize();
     };
9. In section 7.4.4 on page 60, change the return type of the narrow
   method from java.rmi.Remote to java.lang.Object.  In the 
   description of narrow, change "object reference" to "object 
   reference or local object".
 
   Simon
-- 
Simon C Nash, IBM Java Technology Centre, Hursley, UK
MailPoint 146, x245156  Tel. 01962 815156 or +44-1962-815156
Internet: nash@hursley.ibm.com  Notes mail: Simon Nash@ibmgb