EAI - Enterprise Application Integration, the understanding!

Today I thought of sharing some simple concepts of Enterprise Application Integration (EAI). What is this all about? Types of EAI, and its methodologies. From my personal experience at times we forget about the most basic things in our life. Some definition are too tough to explain or if someone is gathering some information or basic knowledge; such handy tips always help us.

So I am sharing a vast topic but with a simple and basic definition –

What is EAI?

EAI (i.e. enterprise application integration) is a business computing term used for the methods, plans, and tools that are aimed at revolutionizing, consolidating, and handling all the computer applications in an enterprise.

Fundamentally, it is all about sharing and distributing data and processes amongst different applications and data sources of that enterprise.

We all know, an enterprise platform has an existing legacy applications and its databases that need to be continued as per the requirements and need however, in addition to that we put a new set of applications that are used in the Internet, e-commerce, extranet, and other new technologies within the enterprise.

Types of EAI

Its majorly distinguish into 4 integration levels:

1. Data Level
2. Application Interface Level
3. Method Level
4. User Interface Level

Data Level: It is actually a database-centric approach that involves the extracting of data from one database and updating it in other. At times the extracted data can be changed before entering it into that target database, for example, to apply specific business rules. It’s commonly done through ETL (Extract, Transform, and Load).

The main benefits of this approach are its low cost and low risk profile. Because in this, we don’t have to make any modifications to the existing code of the application. So, we don’t need to undergo any expenses related to the developing, testing, or deploying any new sorts of these applications.

Application Interface Level: It consists of leveraging the interfaces distributed by custom or packaged applications to access business processes and easy information. Usually, this kind of integration is done in a three-step process:

1. Extract the information from one application through a provided application interface.
2. Convert the data in a format understandable by the target application.
3. Transmit the information to the target application.

The main benefits of this approach are the point that the interfacing between the different applications is easy due to the fact that the application interfaces are provided by application. A negative aspect of this approach is the cost of the message broker technology.

Method level: It is actually similar to application interface level but have a lower level of granularity. Here, idea here is not to share any business functions (as in application interface level), but to share directly the different methods used to compose a given business function. In this, methods can be reuse for business logic

User Interface Level: It’s commonly known as "Refacing" and consists of substituting existing text-based user interfaces of the legacy systems and graphical interfaces of PCs by a standardized interface, typically known as browser-based. This kind of integration is less expensive than any other approaches, as the code of the existing applications is not revised. However, this approach is then less flexible too.

What are the Methodologies?

EAI includes methodologies like –

• Distributed, cross-platform program communication using message brokers with Common Object Request Broker Architecture and COM+
• Object-oriented programming
• Enterprise-wide content and data distribution using common databases and data standards implemented with the Extensible Markup Language (XML)
• Modification of enterprise resource planning (ERP) to fit new objectives
• Middleware, message queuing, and other approaches.

For further reading and other references are –

• David Linthicum, Next Generation Application Integration: From Simple Information to Web Services, Addison-Wesley, 2003.
• Michael-richardson.com
• Gregor Hope and Bobby Woolf, Enterprise Integration Patterns, Addison-Wesley, 2003.
to make this approach very suited for EAI.