Component Selection and Specification

Component Selection and Specification

Problem

Very often requirements for IT systems begin life as business process descriptions.

How do these translate into specifications for components that will support the process?
What effect does physical distribution have on the translation process?

An example BPD is given below.

What is the set of components that best supports this?
Is the resulting solution a distributed system? If so, why?

Example

Diagram

Step definitions

Customer submits order

The Customer submits and order for goods to the sales office in London.

Order valid?

The order is valid if:

The address given has a valid postcode
The goods ordered are in stock

New customer?

The customer is new if the name and address does not match a record on file.

Accept order?

An order from a new customer is accepted only if the Credit Controller agrees. If so, the new customer details are put on file.

Notify customer

The customer is called by the Credit Controller or Sales Clerk and told why their order is not accepted.

Transmit invoice

An invoice is sent to the customer.

Notify warehouse

The warehouse (in Leeds) is notified of the order.

Assemble order

A Warehouseman picks and packs the order.

Customer pays order

The Customer sends payment for the order. Payment records are updated and the money/cheque is banked. Note that credit-card payments are not accepted.

Ship order

A Post Room Worker prepares the order for shipping.

Close order

An audit entry for the order is written to file.