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Updated internet draft: draft-ryan-corba-schema-01
Based on feedback from reviewers, the internet-draft:
'Schema for Representing CORBA Object References in an LDAP Directory'
has been revised. The updated version is draft-ryan-corba-schema-01
(attached) and will be available at the following IETF site in the
next few days:
http://www.ietf.org/internet-draft/draft-ryan-corba-schema-01.txt
Please review this version and send your comments to the mailing
list(s).
Thank you.
These are the changes since the -00 version:
- References to 'CORBA object' have been replaced with
'CORBA object reference' to better reflect what is being
stored in the LDAP directory.
- The corbaIor attibute now has case-ignore IA5 String
syntax rather than case-exact Directory String syntax.
- The corbaObject object class is now abstract rather than
auxiliary. (This follows the schema structure in the related
I-D: draft-ryan-java-schema-02.)
- The corbaObjectReference object class is new.
***************************************************************
NOTE: The current release of JNDI 1.2 (Beta) supports the -00
version if this I-D. The final release of JNDI 1.2 will
support this -01 version.
http://java.sun.com/jndi
***************************************************************
INTERNET-DRAFT V. Ryan
Expires 15 December, 1999 R. Lee
S. Seligman
Sun Microsystems, Inc.
12 June, 1999
Schema for Representing CORBA Object References in an LDAP Directory
<draft-ryan-corba-schema-01.txt>
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet- Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
Copyright (C) The Internet Society (1999). All Rights Reserved.
Please see the Copyright section near the end of this document for
more information.
Abstract
CORBA [CORBA] is the Common Object Request Broker Architecture
defined by the Object Management Group. This document defines the
schema for representing CORBA object references in an LDAP directory
[LDAPv3].
1. Introduction
This document assumes that the reader has a general understanding of
CORBA.
Ryan, et. al. [Page 1]
INTERNET-DRAFT Schema for CORBA Object Reference June 1999
Traditionally, LDAP directories have been used to store data. Users
and programmers think of the directory as a hierarchy of directory
entries, each containing a set of attributes. You look up an entry
from the directory and extract the attribute(s) of interest. For
example, you can look up a person's telephone number from the
directory. Alternatively, you can search the directory for entries
with a particular set of attributes. For example, you can search for
all persons in the directory with the surname "Smith".
CORBA applications require access to CORBA objects. Traditionally,
CORBA applications have used the COS Naming service for storage and
retrieval of CORBA object references. When deployed in environments
with a directory, CORBA applications should be able to use the
directory as a repository for CORBA object references. The directory
provides a centrally administered, and possibly replicated, service
for use by CORBA applications distributed across the network.
For example, an application server may use the directory for
"registering" CORBA objects representing the services that it
manages, so that a client can later search the directory to locate
those services as it needs.
The motivation for this document is to define a common way for
applications to store and retrieve CORBA object references from the
directory. Using this common schema, any CORBA application that
needs to read or store CORBA object references in the directory can
do so in an interoperable way.
Note that this schema is defined for storing CORBA "object
references," not CORBA objects in general. There might be other ways
to store CORBA objects in an LDAP directory but they are not covered
by this schema.
2 Representation of CORBA Object References
This document defines schema elements to represent a CORBA object
reference in LDAP directory. Applications in possession of a
reference to an object can invoke calls on that object. Such a
reference is termed an "interoperable object reference," or IOR.
Access to CORBA objects by using IORs is achieved transparently to
the application, by means of the Internet Inter-ORB Protocol.
A CORBA object reference is represented in the directory by the
object class corbaObjectReference. corbaObjectReference is a subclass
of the abstract corbaObject object class. corbaObjectReference is an
auxiliary object class, which means that it needs to be mixed in with
a structural object class.
Ryan, et. al. [Page 2]
INTERNET-DRAFT Schema for CORBA Object Reference June 1999
The object class corbaContainer represents a directory entry
dedicated to storing a CORBA object. It is a structural object class.
corbaContainer is not required when a subclass of corbaObject (such
as corbaObjectReference) is mixed in with another structural object
class.
The definitions for the object classes corbaObject,
corbaObjectReference, and corbaContainer are presented in Section 4.
The corbaObject class has two optional attributes: corbaRepositoryId
and description. corbaRepositoryId is a multivalued attribute that
is used to store the repository ids of the interfaces implemented by
a CORBA object. description is used to store a textual description
of a CORBA object.
The corbaObjectReference class has one mandatory attribute: corbaIor.
corbaIor is used to store the object's stringified IOR.
corbaIor and corbaRepositoryId are defined in Section 3; description
is defined in [v3Schema].
3 Attribute Type Definitions
The following attribute types are defined in this document:
corbaIor
corbaRepositoryId
3.1 corbaIor
This attribute stores the string representation of the interoperable
object reference (IOR) for a CORBA object. An IOR is an opaque handle
for the object which contains the information necessary to locate the
object, even if the object is in another ORB.
This attribute's syntax is 'IA5 String' and its case is
insignificant.
Ryan, et. al. [Page 3]
INTERNET-DRAFT Schema for CORBA Object Reference June 1999
( 1.3.6.1.4.1.42.2.27.4.1.14
NAME 'corbaIor'
DESC 'Stringified interoperable object reference of a CORBA object'
EQUALITY caseIgnoreIA5Match
SYNTAX 1.3.6.1.4.1.1466.115.121.1.26
SINGLE-VALUE
)
3.2 corbaRepositoryId
Each CORBA interface has a unique "repository id" (also called "type
id") that identifies the interface. A CORBA object has one or more
repository ids, one for each interface that it implements (for
example, as a result of interface inheritance).
The format of a repository can be any string, but the OMG specifies
four standard formats:
a. IDL-style
IDL:Prefix/ModuleName/InterfaceName:VersionNumber
For example, the repository id for the "NamingContext" in OMG's COS
Naming module is: "IDL:omg.org/CosNaming/NamingContext:1.0".
b. RMI-style
RMI:ClassName:HashCode[:SUID]
This format is used by RMI-IIOP remote objects [RMI-IIOP].
"ClassName" is the fully qualified name of the class (for example,
"java.lang.String"). "HashCode" is the object's hash code (that is,
that obtained by invoking the "hashCode()" method). "SUID" is the
"stream unique identifier", which is a 64-bit number that uniquely
identifies the serialization version of the class; SUID is optional
in the repository id.
c. DCE-style
DCE:UUID
This format is used for DCE/CORBA interoperability [CORBA-DCE].
"UUID" represents a DCE UUID.
d. "local"
Ryan, et. al. [Page 4]
INTERNET-DRAFT Schema for CORBA Object Reference June 1999
This format is defined by the local Object Request Broker (ORB).
The corbaRepositoryId attribute is a multivalued attribute; each
value records a single repository id of an interface implemented by
the CORBA object. This attribute need not contain a complete list of
the interfaces implemented by the CORBA object.
This attribute's syntax is 'Directory String' and its case is
significant.
( 1.3.6.1.4.1.42.2.27.4.1.15
NAME 'corbaRepositoryId'
DESC 'Repository ids of interfaces implemented by a CORBA object'
EQUALITY caseExactMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.15
)
4 Object Class Definitions
The following object classes are defined in this document:
corbaContainer
corbaObject
corbaObjectReference
4.1 corbaContainer
This structural object class represents a container for a CORBA
object.
( 1.3.6.1.4.1.42.2.27.4.2.10
NAME 'corbaContainer'
DESC 'Container for a CORBA object'
SUP top
STRUCTURAL
MUST ( cn )
)
Ryan, et. al. [Page 5]
INTERNET-DRAFT Schema for CORBA Object Reference June 1999
4.2 corbaObject
This abstract object class is the root class for representing a CORBA
object.
( 1.3.6.1.4.1.42.2.27.4.2.9
NAME 'corbaObject'
DESC 'CORBA object representation'
SUP top
ABSTRACT
MAY ( corbaRepositoryId description )
)
4.3 corbaObjectReference
This auxiliary object class represents a CORBA object reference. It
must be mixed in with a structural object class.
( 1.3.6.1.4.1.42.2.27.4.2.11
NAME 'corbaObjectReference'
DESC 'CORBA interoperable object reference'
SUP corbaObject
AUXILIARY
MUST ( corbaIor )
)
5. Security Considerations
Obtaining a reference to an object and storing it in the directory
may make a handle to the object available to a wider audience. This
may have security implications.
6. Acknowledgements
We would like to thank Sanjeev Krishnan of Sun Microsystems, Simon
Nash of IBM, and Jeffrey Spirn of Oracle for their comments and
suggestions.
7. Copyright
Copyright (C) The Internet Society (1999). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
Ryan, et. al. [Page 6]
INTERNET-DRAFT Schema for CORBA Object Reference June 1999
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
8. References
[CORBA] The Object Management Group, "Common Object Request Broker
Architecture Specification 2.2," http://www.omg.org
[CORBA-DCE] Distributed Systems Technology Center and Digital
Equipment Corporation, "DCE/CORBA Interworking Specification," May
1998.
http://www.omg.org/library/schedule/DCE_CORBA_Interworking_RFP.html
[LDAPv3] M. Wahl, T. Howes, S. Kille, "Lightweight Directory Access
Protocol (v3)," RFC-2251, December 1997.
http://www.ietf.org/rfc/rfc2251.txt
[RMI-IIOP] IBM and Java Software, Sun Microsystems, Inc., "RMI over
IIOP," June 1999. http://java.sun.com/products/rmi-iiop/index.html
[v3Schema] M. Wahl, "A Summary of the X.500(96) User Schema for use
with LDAPv3," RFC-2256, December 1997.
http://www.ietf.org/rfc/rfc2256.txt
9. Authors' Addresses
Ryan, et. al. [Page 7]
INTERNET-DRAFT Schema for CORBA Object Reference June 1999
Rosanna Lee
Sun Microsystems, Inc.
Mail Stop UCUP02-206
901 San Antonio Road
Palo Alto, CA 94303
USA
+1 408 863 3221
rosanna.lee@eng.sun.com
Vincent Ryan
Sun Microsystems, Inc.
Mail Stop EDUB03
901 San Antonio Road
Palo Alto, CA 94303
USA
+353 1 819 9151
vincent.ryan@ireland.sun.com
Scott Seligman
Sun Microsystems, Inc.
Mail Stop UCUP02-209
901 San Antonio Road
Palo Alto, CA 94303
USA
+1 408 863 3222
scott.seligman@eng.sun.com
10. Appendix - LDAP Schema
-- Attribute types --
( 1.3.6.1.4.1.42.2.27.4.1.14
NAME 'corbaIor'
DESC 'Stringified interoperable object reference of a CORBA object'
EQUALITY caseIgnoreIA5Match
SYNTAX 1.3.6.1.4.1.1466.115.121.1.26
SINGLE-VALUE
)
( 1.3.6.1.4.1.42.2.27.4.1.15
NAME 'corbaRepositoryId'
DESC 'Repository ids of interfaces implemented by a CORBA object'
EQUALITY caseExactMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.15
)
-- from RFC-2256 --
Ryan, et. al. [Page 8]
INTERNET-DRAFT Schema for CORBA Object Reference June 1999
( 2.5.4.13
NAME 'description'
EQUALITY caseIgnoreMatch
SUBSTR caseIgnoreSubstringsMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.15{1024}
)
-- Object classes --
( 1.3.6.1.4.1.42.2.27.4.2.9
NAME 'corbaObject'
DESC 'CORBA object representation'
SUP top
ABSTRACT
MAY ( corbaRepositoryId description )
)
( 1.3.6.1.4.1.42.2.27.4.2.10
NAME 'corbaContainer'
DESC 'Container for a CORBA object'
SUP top
STRUCTURAL
MUST ( cn )
)
( 1.3.6.1.4.1.42.2.27.4.2.11
NAME 'corbaObjectReference'
DESC 'CORBA interoperable object reference'
SUP corbaObject
AUXILIARY
MUST ( corbaIor )
)
-- Matching rule from ISO X.520 --
( 2.5.13.5
NAME 'caseExactMatch'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.15
)
Ryan, et. al. [Page 9]