Database Reference
In-Depth Information
SCA components to be realized through a technology-agnostic generic programming
model that decouples the components' implementation from their communication, allow-
ing a high level of reuse. JBI SEs communicate with each other at the technology level,
leaving business communications to the services. This communication model is defined as
a WSDL contract that we mentioned earlier. All communications are decoupled by a mes-
sage dispatcher, called the
normalized message router
(
NMR
), which physically support
all MEPs, as declared in WSDL.
Ideally, we should be able to choose any engine for our abstract operation (that is, trans-
formation or BPEL interpretation) and use a certain engine in any part of our frameworks.
In fact, the Rule Engine and its SDK are unified across the Oracle Service Bus, orchestra-
tion, and even DB. (It is worth mentioning here that the Glassfish application server and
OpenESB support JBI.)
From a service implementation prospective, architects should realize that the service mod-
els (such as entity, utility, or task) define the needs of certain engines. Therefore, the task-
orchestrated services are rather special, as they strongly require the BPEL engine along
with the DB infrastructure, as compared to the simple utility service, which can be imple-
mented as a lightweight portable jar. Service layering within Service Inventory must be
done with extra caution to avoid performance overhead and excessive infrastructure costs.
The design time part of Fusion Middleware hosts the rest of the compulsory frameworks
such as the XML and Object Development frameworks and Automated Testing and
Deployments frameworks. They are covered by several Oracle tools, linked to the source
control and the Enterprise Repository. The two main developer tools are JDeveloper and
Eclipse with the Oracle pack for OSB.
The security layer is a form of ESB as it basically serves similar features such as message
screening (a form of validation), transformation, and exposure-only services designated
for the outside world (that is, hiding and abstracting the internal Service Inventory). So,
can it be implemented using Oracle Service Bus? Hmmm…yes! Firstly, OSB is integrated
with
Oracle Web Service Manager
(
OWSM
). OWSM allows you to define policies,
store them in the policy store, and attach them to a particular service. OSB can support
message encryption and digital signature, the two main mechanisms for establishing mes-
sage confidentiality, nonrepudiation, and integrity. Integrity guarantees that a message has
not been altered on transit, confidentially ensures that only authorized people or processes
have access to the message's content, and nonrepudiation signifies that the act of message
transmission cannot be denied by the sender.
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