WebSphere

An ESB in a stock quote scenario

The stock quote scenario shows a business scenario for getting stock quotes, that is implemented using the IBM® service connectivity scenario.

Introduction

This scenario assumes a financial services company that provides stock quotes. The company has a number of existing information technology (IT) services that must be reused under new business conditions.

A stock quote sample is provided with WebSphere® Enterprise Service Bus and WebSphere Process Server. For more information on the sample, see: Click this link to go to the topic for WebSphere ESB. Click this link to go to the topic for WebSphere Process Server.

Requirements

After analysing their business processes the company defines the following, SOA-related, business requirements:
  • Different levels of service must be provided, depending on the type of customer making the request. To start with there will be two types of customers: standard customers and premium customers.
  • If the company creates further levels of service, these must be added without impacting existing customers.
The business requirements lead to the following IT requirements:
  • Flexibility and reusability requirements. The solution must be flexible, scalable and reusable; therefore, the services must be loosely coupled.
    • The service requester only needs to know the interface to invoke, rather than the location, or physical nature, of the endpoint.
    • Messages and interfaces must be defined using WSDL.
    • The service requester provides the customer identifier, in the input message; and the ESB routes the service request based on the customer identifier.
    • Customer details must be stored in a database and accessed using a customer identifier.
    • The solution must be able to transform the format of a request or response, because the service requester and service providers use different message formats.

Stock quote scenario version 1.0

The stock quote scenario uses a customer identifer to look up customer details in a database, and the customer details are used to route the message. The stock quote scenario assumes that an input message needs its message body transforming to make it suitable for a service endpoint.
Figure 1. Service connectivity scenario for stock quotes: overview
A service connectivity scenario showing a message being routed using from a service requester to a service provider.

In version 1.0 of the scenario, stock quote inquiries are routed to one of two service providers. However, the flexibility and scalability of the ESB mean that you can add service providers, and change the existing service endpoints, without impacting the service requesters.

Version 1.0 of the scenario stores endpoint addresses in a mediation module. However, later versions of the scenario store endpoint addresses in a database, or a registry, for increased flexibility and governance.

The following message flow shows the ESB:
  • Logging the input message, (for audit purposes).
  • Looking up customer details, using a customer identifier.
  • Routing the message, based on the customer details.
  • Transforming the message format, so that it is suitable for the service provider.
Figure 2. Service connectivity scenario for stock quotes: version 1.0 message flow overview
This figure shows an example of message routing

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Timestamp icon Last updated: 20 June 2010 00:38:46 BST (DRAFT)


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