| Bacchus has been long-time
business partners with IBM. Our development environment
has been based on VisualAge Smalltalk for more than 10 years.
VisualAge is a pure object-orientated language which allows
for the rapid development of portable, scalable, multi-tier
business applications. As we have also learnt in recent
years, VisualAge is the ideal architecture to deliver the
frameworks required for Web Services.
VisualAge provides a framework that enable e-business services
to be described, published, discovered, and invoked dynamically
in a distributed computing environment. The Web Services
are self-contained, modular applications that can be:
- Described using a service description
language. The description language that is being used
is WSDL (Web services Description Language).
- Published by registering their descriptions
and use policies with a well-known registry. The registry
being supported is the UDDI (Universal Description, Discovery
and Integration) registry.
- Found by sending queries to UDDI registry
and receiving the binding details of the service(s) that
fit the parameters of the query.
- Bound by using the information contained
in the service description to create a callable service
instance or proxy.
- Invoked over a network by using the
information contained in the binding details of the service
description.
- Composed with other services into new
services and applications.
VisualAge Web services have focused on enhancing the ability
of a Web service to be found, bound, invoked and composed,
which provides a robust and extensible Web services platform
that promotes maintenance of the object paradigm when building
Web services in Smalltalk.
Fundamentally, Web services are nothing more than a set
of distributed computing specifications that describe how
to marshal objects from one endpoint to another over a particular
transport. Many of the specifications, for example the Web
Services Definition Language (WSDL) describe the types and
message structure of a Web service.
Successful applications in Smalltalk rely on object models
that accurately represent a specific user domain. Therefore,
the VisualAge Smalltalk Web services platform was designed
to automatically serialize and de-serialize objects based
upon the (WSDL) description of a service.
To support automatic object conversion, new content handlers
were created for usage with the XML SAX parser. With a minimal
amount of mapping for complex types, users will be able
to work with objects from their business domain.
So, why go for Smalltalk?
"Over-complexity? Gartner reports that 70% of Java projects
fail. They also report that something like 80% of J2EE projects
don't use EJB (or much at all from J2EE) - mostly they use
these products as scalable app servers for JSP. That's an
awfully expensive strategy"...James Robertson, Product Manager,
Cincom Smalltalk
See also: http://www.cincomsmalltalk.com/blog/blogView?showComments=true&entry=3217524055
With Web services support, VisualAgeŽ Smalltalk V6.0 promotes
the creation of self-contained, modular applications. Using
industry-standard protocols such as Simple Object Access
Protocol (SOAP) messaging and WebSphereŽ Open Servlet Engine
(OSE) plug-in, our existing Smalltalk code can be integrated
with anyone, anywhere on the net.
Features include:-
- One-step deployment of proxy services based upon the
Web Services Definition Language (WSDL)
- Pluggable transport mechanism (HTTP and HTTPS e.g.)
- Ability to host Web services
- Ability to wrap existing business objects and expose
them as Web services
Secure Socket Layer (SSL) support enables our applications
to use Open SSL to heighten security for any transactions
running over TCPIP.
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