The Need for Service-Orientation (Part I)
After repeated generations of traditional distributed solutions, the severity of the previously described problems has been amplified. This is why service-orientation was conceived. It very much represents an evolutionary state in the history of IT in that it combines successful design elements of past approaches with new design elements that leverage conceptual and technology innovation.
The consistent application of the eight design principles we listed earlier results in the widespread proliferation of the corresponding design characteristics:
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increased consistency in how functionality and data is represented
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reduced dependencies between units of solution logic
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reduced awareness of underlying solution logic design and implementation details
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increased opportunities to use a piece of solution logic for multiple purposes
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increased opportunities to combine units of solution logic into different configurations
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increased behavioral predictability
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increased availability and scalability
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increased awareness of available solution logic
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When these characteristics exist as real parts of implemented services they establish a common synergy. As a result, the complexion of an enterprise changes as the following distinct qualities are consistently promoted:
Increased Amounts of Agnostic Solution Logic
Within a service-oriented solution units of logic (services) encapsulate functionality not specific to any one application or business process. These services are therefore classified as agnostic and reusable IT assets.
Figure: Business processes are automated by a series of business process-specific services (top layer) that share a pool of business process-agnostic services (bottom layer). These layers correspond to the task, entity, and utility service models described at www.WhatIsSOA.com.
continued on next page...
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