Distributed Objects technology is all about having co-operating objects anywhere on a network. As such, it can (will be?) more powerful than current client/server and database technologies. True distributed objects require many features which are not readily apparent. CORBA has defined many of these and at various layers, as has OLE/COM.
So what are distributed objects? Take my course ;-) But seriously, CORBA does as good a job as any at thinking about objects. Start with services and add layers. The Corba services include: object life cycle, naming, persistence, relationships, querying, concurrency, transactions, security, collections ( abstract data types ), externalization, events, and a few others. Then you layer on integration with the UI via OpenDoc. We won't worry ourselves too much with picky details like requirements tracking, testing. As none of commercial products are available on all platforms, with Java interfaces, asynchronous messaging, integrated with OLE/COM (except OLE/COM), lightweight Java clients, an architect has quite a job to do.
A summary of some information and places to find more might be in order.
The most complete page on all facets of object-orientation is Cetus - Some Links: Object-Orientation
Contents:
CORBA
OpenDoc
Beans
Microsoft
CORBA Orbs
Java Orbs
Articles
Conferences
Persistence
Modeling Tools
OpenDoc layers upon CORBA to provide structured storage and merging of UI features. Some of the same features and more as OLE.
CI Labs is responsible for the OpenDoc standard
Bill has migrated everywhere. COM contains interfaces for how talk to objects, OLE provides the structured storage and merging of UI features. ActiveX provides a standard for integrating components using OLE together. Yeah, this is sparce.. more later.
Iona, jointly owed by Sun, makes Orbix, a CORBA 2.0 compliant ORB for 21 platforms, including OS/2, AIX, NT, 95, etc. Tight integration with OLE/COM Few Object Services supported. Java IDL mapping
PostModern Computing Offers ORBeline, a CORBA 2.0 compliant ORB for many platforms. Web pages have not been kept up. Unknown Object Services support. Java IDL mapping via Black Widow
IBM offers SOM, a CORBA 2.0 compliant ORB for windows, OS/2. SOM is the basis for OpenDoc. No Java IDL mappping. Naming, Persistence, Event, Transaction, Concurrence, LifeCycle, Security, Externalization Common Object Services supported, as well as proprietary Collection and Binary compatibility between object versions (No fragile base class problem Microsoft..) Looks like Iona has adopted SOM
DEC offers ObjectBroker a CORBA 1.2 compliant ORB for 20 platforms, including NT, 95, All major Unixi, . DCE Security and Tight OLE/COM integration - without recompiling, objects can be treated as COM/OLE objects. Nifty Explorer of Remote objects. No Java IDL binding. Poor Web site. Unknown COS.
Expersoft offers PowerBroker, a CORBA 2.0 compliant ORB. Heavy PR for asynchronous messaging, only Life-Cycle and naming CORBA Services. Objects also comply with OLE/COM. Available for all Unixi including AIX, as well as NT, but NO 95. It really touts itself as a development environment. No Java IDL binding.
HP offers ORBPlus, a CORBA 2.0 compliant ORB with events, naming and life-cycle CORBA Services.
Comparison Between Object Oriented and Relational Databases
OODBMS
Gemstone offers a leading OODBMS. However, you have to use Smalltalk to interface.
Gensym's ReThink is a modeling tool, highly recommended by Kalev Ruberg, IBM's ICBC project architect.
MultiQuest makes S-CASE, supports Booch and UML, Outputs C++ using TCL ( but could be customized for Java ), Avail for 95/NT. $495 for single-user, $795 for floating license. Version 2.1 has no UML but avail for OS/2.
Verilog makes ObjectPartner, an OMT compliant CASE tool for Unixii and NT, outputs many C++ types - only Microsoft C++ 2.0 though… Has all 4 models - object, use-case, dynamic and data flow. Has template mechanism to handle language, platform, and coding standard changes. No pricing available
Dirk makes Object Domain, a $100 tool which is Booch and OMT compliant. 6 booch models, missing the data flow diagram for OMT. Very powerful Object editor though, handles many aspects of attributes, visibility, behaviour. Fonts can be a bit ugly.
Rational Rose is another modelling tool.