Software Architecture

What is soa:

It’s an approach that helps systems remain scalable and flexible while growing, and that also helps bridge the business/IT gap.

The approach consists of three major elements:

A service is a piece of self-contained business functionality. The functionality might be

simple (storing or retrieving customer data), or complex (a business process for a customer’s

order). Because services concentrate on the business value of an interface, they

bridge the business/IT gap.

An enterprise service bus (ESB) is the infrastructure that enables high interoperability

between distributed systems for services. It makes it easier to distribute business processes

over multiple systems using different platforms and technologies.

Loose coupling is the concept of reducing system dependencies. Because business processes

are distributed over multiple backends, it is important to minimize the effects of

modifications and failures. Otherwise, modifications become too risky, and system failures

might break the overall system landscape. Note, however, that there is a price for

loose coupling: complexity. Loosely coupled distributed systems are harder to develop,

maintain, and debug.

SOA is a paradigm for improved flexibility

Loose coupling is the concept of minimizing dependencies. When dependencies are minimized, modifications have minimized effects, and the systems still runs when parts of it are broken or down. Minimizing dependencies contributes to fault tolerance and flexibility

The key feature of the ESB is that it enables you to call services between heterogeneous

systems. Its responsibilities include data transformation, (intelligent) routing, dealing with

security and reliability, service management, monitoring, and logging.

SOA is not the same as Web Services.

SOA is the paradigm; Web Services are one possible way to realize the infrastructure

by using a specific implementation strategy.

One type of interface is a signature,...