Managing Information Access to an Enterprise Information System Using J2EE and Services Oriented Architecture

Chapter 7. Using Web services 169

7.2 Web services for EIS integration

In general Web services are appreciated for the following reasons:

򐂰 Interoperability

Any Web service can interact with any other Web service. Thanks to SOAP,

the new standard protocol supported by all of the major vendors (and most of

the minor ones too), the difficulties of converting between CORBA, DCOM,

and other protocols should be over. Because Web services can be written in

any language, developers do not need to change their development

environments to produce or to use Web services.

򐂰 Ubiquity

Web services communicate using HTTP and XML. Therefore, any device

which supports these technologies can both host and access Web services.

Soon, Web services will be present in phones, cars, and even soda

machines. If the soda supplies are getting low, then soda machine can

contact the local supplier's Web service via a wireless network and can order

what it needs.

򐂰 Low barrier to entry

The concepts behind Web services are easy to understand. Many vendors

such as IBM and Microsoft offer tools that allow developers to quickly create

and deploy Web services. In addition, some of these tools allow pre-existing

COM components and JavaBeans to be easily exposed as Web services.

򐂰 Industry support

All of the major vendors are supporting SOAP and the surrounding Web

services technology. For example, WebSphere Application Server supports

these technologies inside the J2EE architecture, and the Microsoft.NET

platform supports all the proprietary Microsoft languages.

The following sections explain why Web services are ready for an extensive

deployment in scenarios that integrate business partners and that expose

existing enterprise information systems (EIS).

7.2.1 Integrate business partners

A current business and technology challenge is to accelerate inter-company

communication to gain more reactive business. Web services provide a low cost

technology to realize this kind of need. When a new technology is introduced in

the business activity, it is important for technology to offer a strong quality of

service.

170 Managing Information Access to an EIS Using J2EE and Services Oriented Architecture

In the scenario (described in Chapter 3, “Scenario overview and design” on

page 65), we introduced Web services technology because the relationship

between the bank and the stock analyst firm is changeable partnership and

cannot justify the implementation of a private communication infrastructure. The

bank wants to provide a new service which prevents its customers from buying

stocks that fluctuate wildly in value. To give impartial advice, the bank relies on

an external information service that is provided by a specialized stock analyst

firm.

As in our scenario, there are several situations that have similar conditions and

requirements:

򐂰 The business does not justify a private network.

򐂰 There is a need to exchange information with a remote partner.

򐂰 The service request does not have a side effect on the remote system (basic

inquiry).

򐂰 The service request triggers a remote transaction; however, that transaction

can be isolated by a local one.

򐂰 There is a need for quick implementation.

Web services technology can provide answers to each of these requirements.

7.2.2 Expose the EIS

In almost all organizations, it is common to find a great variety of software

platforms provided by different software vendors. In addition to mainframe

solutions, there are many vertical solutions for ERP, eCommerce, Office

Automation, CRM, and so on. There is also horizontal application technology for

client and server computing such as J2EE application servers and Microsoft.Net.

Niche technology (for example PHP, Perl, Python, and Borland Delphi) can also

be used.

To make this different software work together, there are two options:

򐂰 Create an ad-hoc point-to-point translator.

򐂰 Modify all the components to speak a common language.

The first option leads potentially to the implementation of (n-1)! translator. The

second option, in the worst case, leads to the implementation of n translator. In

the recent years, many software vendors have provided Web services

implementation. The choice to use the Web services as a common language is

one of the least expensive and most viable options.

Many legacy EIS solution do not offer Web services interfaces, or if they do offer

an interface, it often lacks in terms of features. So, we suggest that you wrap