Enterprise application integration methods

 So done with choosing the right integration architecture? Now its time to choose the right integration method. Let's have a look at them.

EAI has five common integration methods:

• Data-level integration
• User interface (UI)-level integration
• Application-level integration
• Method-level integration

Lets have a quick run through each of them.

DATA LEVEL INTEGRATION

Data level integration can be push or pull. ie push based integration or pull based integration.With push-based, one application makes SQL calls (through database links or stored procedures) on another application's database tables. Push-based data-level integration pushes data into another application's database. In contrast, pull-based data-level integration utilizes triggers and polling. Triggers capture changes to data and write the identifying information to interface tables. Adaptors can then poll the integrated application's interface tables and retrieve the pertinent data. You'd use pull-based data-level integration when an application requires passive notification of changes within another application's data.

UI LEVEL INTEGRATION

This is where the logic is tied to the user interface code. Again here we can have two classification.It can be scripting based or proxy based.

Scripting-based UI-level integration embeds integration code into the UI component events, common with client/server applications such as PowerBuilder or Vantive. For example, when you click the Submit button of an Add Customer screen, data must be sent to the application's database and a JMS (Java Message Service) topic. Proxy-based UI-level integration uses the integrated application's interface (through screen scraping) to pass data to and from the legacy system.

APPLICATION LEVEL INTEGRATION

This is probably the best way of integration. This uses the integrated application's integration frameworks and APIs. Application interfaces let you invoke business logic to preserve data integrity. Integration API examples include Siebel's Java DataBeans and SAP's JCA (J2EE Connector Architecture). Prefer application-level integration because it is transparent to the integrated application and preserves the application's data integrity.

METHOD LEVEL INTEGRATION

 
Method-level integration, a less frequently used superset of application-level integration, aggregates common operations on multiple applications into a single application that fronts the integrated applications.

Use method-level integration when each integrated application provides a similar set of API or functional methods. Typically, you'd create an aggregating (front) application, which fronts the aggregated applications using distributed components (CORBA, Enterprise JavaBeans (EJB), DCOM (Distributed Component Object Model), and so on).