Java Reference
In-Depth Information
Concerns
• The Spring MDP is easy to develop and use but is not based on Java EE standard
specifications. Using the MDP and Spring message container may not be suitable
for large-scale enterprise requirements.
Web Service Broker
Problem
Generating policy quotations was one very important service provided by the eInsure
application. This service would accept the bare minimum information: the policy
amount, the number of years of coverage (the “term”), the frequency of premiums, and,
of course, the insurance product against which the policy is underwritten. Given these
inputs, the output would be the tentative premium to be paid by the client.
This service was available in the online eInsure application and was used heavily
at the counters by the underwriters and support executives. However, the partners,
resellers, and agents of the company using eInsure but without direct access to the appli-
cation also wanted to use this functionality. There were others like the affiliates who
wanted to integrate only this functionality into their utility web sites as widgets. The pol-
icy quotation service was accessible remotely through a session facade. However, the
actual functionality was implemented as a POJO application service. Most of these exter-
nal applications were running on PHP, and others were running on the Microsoft .NET
platform. It is possible to have a non-Java client for EJB, but this was not within the skill
set of the team developing those external applications. In such situations, an alternative
is to expose these services in a technology- or platform-independent manner. Web serv-
ices are a perfect solution. Exposing the policy quote function as a web service would
enable any external application to consume it without being inhibited by technology
barriers.
Forces
• It is required to expose internal services to external clients.
• The services should be exposed in a technology-neutral way.
• Open standards are preferred for exposing services while integrating with external
systems.
