Can CORBA & Web services live together?
Web services, once hyped as the replacement for corba, is now being
repositioned as a technology that can coexist with CORBA. It is not just the
smaller players who are saying this: Microsoft, the main driver behind Web
services, has now taken this stance. Still, a few die-hards insist Web services
is the next technology wave.
However, the move toward coexistence has been boosted by the Object
Management Group (OMG), which owns the CORBA specification. The OMG is planning
additions to CORBA that would see CORBA and Web services come under the umbrella
of the organization's Model Driven Architecture (MDA).
Why the shift in thinking? First, Web services vendors are recognizing that
corporations have invested so much in legacy systems, including CORBA, that they
do not want to throw them away. Second, Web services lacks fundamental, robust
functionalities such as authentication, security and access control. This
renders them unfit for prime-time, mission-critical applications, especially
outside the corporate firewall.
The result: Microsoft and other vendors in both the CORBA and Web services
markets agree that Web services will be used as a front end to legacy systems.
Many observers say Web services will leverage CORBA's robust security features.
Web services believers
Robert Wegener, national
director, solutions, at the Chicago offices of technology consultants RCG
Information Technology, is among those who believe Web services will replace
''I see CORBA just dropping off. Why would you use the proprietary stuff when
you have all the open-source Web services?,'' said Wegener, who has extensive
experience in various process, development, QA and testing methodologies. He
believes the migration of the installed base over to Web services is ''a natural
progression, especially for people who are already doing distributed processing.
This will be a no-brainer.''
Wegener said Web services will get a boost because large vendors such as
PeopleSoft and Oracle are adding Web services to their products; in addition,
SAP has exposed ''about 500 Web services'' in MY SAP for its supply chain.
Further, larger companies will push Web services to suppliers because ''they can
offload processing power to other people,'' Wegener explained. He predicted that
some of the larger companies -- ''the Wal-Marts, Sears, General
Motors'' -- will be doing this ''within one year.''
Unlike the push to do business with suppliers over EDI -- which failed
because it required heavy investment in equipment and services -- this push
with Web services will succeed because ''the technology is in place -- most
people have an application server so they won't need to make an infrastructure
change,'' Wegener explained, ''and those people who don't have the
infrastructure can get cheap solutions out there.''
For example, brokers will spring up who own UDDI directories for Web services
and will let people use their Web services for a fee, Wegener said. Smaller
companies will be able to use the services of such brokers relatively
inexpensively, he added.
Another believer is Anne Thomas Manes, chief technology officer at Cambridge,
Mass.-based Systinet Corp., which builds Web services infrastructure such as
SOAP and UDDI servers. ''I would not qualify CORBA as dead, but it has
definitely been hospitalized,'' she said. CORBA ''has always been a niche
player; it has never been a pervasive technology because it is very hard to use.
Java and J2EE are much more easy to use than CORBA,'' she added.
The advantage of Web services is faster time to market, Manes said. For
example, one Systinet customer making network devices is ''very concerned with
processing speed'' because it processes large amounts of traffic going over the
network. That customer is considering a Web services router device to handle the
traffic. The alternative is to build the device with CORBA or a proprietary
Using CORBA would require ''maybe six engineers who understand the
stuff -- which means they're very, very expensive -- and they'd have
to work for nine months, and it would cost X dollars to accomplish that. Or they
could take much more junior programmers who understand Web services, have them
build it on SOAP in two months, and give them a much bigger piece of hardware to
run on,'' Manes said. The cost to build in Web services would be the same, ''but
they'll get it out to market that much sooner. There's still a tradeoff, but
hardware is so powerful that it's a good tradeoff,'' she said.
Manes agrees that CORBA is more robust than Web services, but ''that's only
because we haven't developed the additional services -- transactions,
security, a naming service -- that normally operate around the CORBA broker
in the Web services world,'' she said. She expects these to be created ''within
the next couple of years.''
Yes, we can all get along
The trouble is that there are
other gaps in Web services technology. ''There's a whole bunch of standards
missing,'' said Eric Blankenburg, engineering director at system integrator
Avanade Inc., Seattle. ''Security, transactions ... How do I compose more than
one service that is not a logical unit of work? Can I not call these services
The solution is a queuing mechanism, but developing the solution has
fragmented the Web services community. ''Microsoft has SOAPR, SOAP Reliable, but
IBM is using HTTPR, which is HTTP Reliable,'' Blankenburg said. To call services
in a non-linear fashion, Microsoft offers XLanguage, while IBM has Web Services
Flow Language, he said.
The result: ''You can do some rudimentary things with Web services, but
that's about all right now,'' Blankenburg said. ''I'm a big fan of Web services,
but to think that somehow this technology is immediately going to replace IIOP,
RMI, or COM and DCOM is a stretch.''
CORBA is not going away anytime soon, if only because the telecommunication
and aircraft industries have a huge installed base of CORBA technology.
''AT&T manages its entire network infrastructure on our stuff,'' said
John Rymer, vice president of product marketing at Iona, a leader in the CORBA
field with headquarters in Dublin, Ireland. ÒBoeing runs its entire aircraft
manufacturing operation -- 70,000 users, 7,000 servers, huge throughput,
multiple plants and sites -- on a CORBA-based architecture, which is our
Tony Goodhew, product manager for .NET Framework at Microsoft Corp., Redmond,
Wash., agrees that Web services will coexist with CORBA because of corporations'
huge existing investments in technology. ''Not throwing away existing
investments makes a lot of sense,'' he said. ''The CORBA guys are right in that
they're going to be around for a long time.''
The strongest argument for coexistence is that Web services do not mean
anything by themselves. ''Web services, as currently formulated, are nothing
more than client/server with XML protocol,'' said Hugh Grant, chief technical
officer, Cape Clear Software, Campbell, Calif., which offers CapeConnect, a
product for integrating Web services with existing systems such as J2EE and
CORBA. ''Web services applications are solving exactly the same problem as
client/server, but not adding business value; whereas if you leverage CORBA or
some other back-end technology with Web services, there's a business win
there,'' he said.
The lipstick on the bulldog
Web services solve the main
problem with CORBA: The front end. ''The Achilles' heel of CORBA development was
always that you'd end up with good servers but getting access to them is a
problem,'' said Cape Clear's Grant, who was previously chief architect at Iona.
This is because ''CORBA is a more technical thing to program and so there
weren't enough front-end developers,'' he said.
Currently, Web services are being used as the best way to Web-enable access
to CORBA systems to link them behind the corporate firewall. At AT&T, for
example, Web services have been defined as the standard for all inter-domain
registration going forward, Iona's Rymer said. AT&T has asked Iona to
''provide Web service front ends to their applications,'' Rymer said. The
payoff: Better integration between the various back-end systems -- such as
billing, customer management, call and marketing systems -- and the front
end, leading to greater efficiency and, ultimately, a stronger bottom line.
Sridhar Iyengar, distinguished engineer, application and integration
middleware at IBM in Irvine, Calif., described Web services as ''the lipstick on
the bulldog.'' The bulldog is ''in back running on a mainframe or a Unix server,
doing core transactions; it's reliable, secure and never fails,'' Iyengar said.
The lipstick is the front end. When a new lipstick comes along, ''you write some
code to generate a wrapper and now you're Web-enabled or Web services-enabled,''
The key thing about Web services, Iyengar said, is that the base standard of
interoperability has been agreed upon ''by everybody,'' which means there is no
differentiation and the playing field gets leveled for certain types of simple
interoperability, for example, among a user's various devices. ''Today, when my
secretary sets up a meeting, I have to synch my Palm and my laptop,'' Iyengar
said. ''And different calendars on PCs have different proprietary standards. But
if we use Web services, synching between Palm and laptop will be as easy as
synching between the Palm and the mainframe. The tough thing in Web services
will be agreeing upon what the schema are.''
There will be a guarantee for interoperability between CORBA and Web services
because the OMG plans to create a standard way of mapping between CORBA's
Interface Definition Language (IDL) and the Web Services Definition Language
(WSDL), which is XML-based, Iyengar said. The OMG already has one request for
proposals (RFP) out on mapping IDL to WSDL, as well as another on mapping WSDL
to IDL. The first ''will let you invoke a CORBA object as a Web service; the
second will let you invoke a Web service to a CORBA object,'' Iyengar said.
The OMG's MDA is ideal for running Web services because ''Web services is the
integration of multiple middleware performing a function that gets exposed as
Web services'' and an MDA development tool ''can generate invocations in any
middleware,'' said Jon Siegel, the OMG's vice president of technology transfer.
''If you have two different platforms with different applications written in
MDA, you just bring them into an MDA tool, draw a line between them, and get the
tool to generate a cross-platform invocation.''
Modifications to CORBA will make it more suitable for transactions over the
Internet. While CORBA has a tightly coupled architecture that is not suitable
for conducting B2B transactions over the Internet, Siegel said this problem has
been solved with a ''very nice'' asynchronous messaging definition, consisting
of asynch invocation interfaces, that was added in CORBA 2.4 (the current
version of CORBA is 2.6). This interface ''goes through the firewall, goes to
Port 80 and looks like HTTP, and everyone says they need it,'' Siegel said. At
the time of his interview for this story, Siegel said a firewall specification
would soon be added.
Mapping to new technologies with MDA will be easy ''because the basic
requirement hasn't changed in 20 years -- you make a request for something
and it comes back,'' IBM's Iyengar said. ''At the end of the day, customers will
be able to use existing Web services with CORBA objects.''
Like COBOL, CORBA is here to stay. And newer technologies will have to cope
with the legacy systems.