Application Integration general guidelines

To help you determine if the Application Integration pattern is appropriate for the design of your Web-based application, the following information details the business and IT scenario into which a solution using the Application Integration pattern will fit. This page also details the e-business services required in an Application Integration solution.

Business and IT Drivers
Businesses developing a solution needing the following characteristics should consider using the Application Integration business pattern:

• The business process needs to be integrated with existing business systems and information.
• The business processes need to integrate with processes and information that exist at partner organizations.
• The business activity has a need to aggregate, organize, and present information from various sources within and outside of the organization.

Context
Application Integration patterns can be observed in solutions that call for close integration with systems and databases that exist within the organization or across organizational boundaries. It serves as a back-end integration pattern, and is critical for the successful implementation of certain Business patterns. For example, it is hard to conceive of a solution that uses the Self-Service business pattern or an Extended Enterprise business pattern without using the Application Integration pattern within it. Similarly, it is hard to think of custom designs and Composite patterns existing without using Application Integration application patterns. Application Integration application patterns can be classified according to the following four (4) attributes:

• By the function or work that they perform:
  • Message pass-thru
  • Message routing
    • Message enhancement
    • Message workflow
• By the focus of integration:
  • Data
  • Process (or Message)
• By the mode of connection deployed:
  • Asynchronous
  • Synchronous
• By the targeted topology:
  • Point-to-point
  • Multi-point

Solution
The Application Integration business pattern typically consists of:

• Business applications and data that need to communicate, interact and integrate with other business applications and data that exists within the organization or in business partner organizations
• A network, which
  • Is based on TCP/IP and other Internet technologies
  • Can be a dedicated LAN connection or WAN connection
• Other business applications and data which can be:
  • Custom developed systems (old and new)
  • Enterprise Resource Planning systems and other Packaged applications such as SAP, BAAN and PeopleSoft
  • Databases
• Application Integration services that include:
  • Protocol adapters
  • Message handlers
  • Data transformation
  • Decomposition/Re-composition
  • Routing/Navigation
  • State management
  • Security
  • Local business logic
  • (Business) unit-of-work management

Putting the Application Integration business pattern to use
This is probably one of the most common patterns and it can be observed in any solution where an application needs to integrate with other applications, legacy systems and databases, or applications and processes in external organizations. Examples include:

• Any online store that needs to integrate the online shopping process with core business systems and databases such as the inventory management system and an order fulfillment system.
• Many Web sites today syndicate content from content providers and integrate this content into their own Web site. In these cases, individual solutions are integrated with an application that exists outside the organization.

What's Next
If you have determined that the Application Integration pattern is appropriate for use in your solution, the next step is to select an Application pattern.

If the Application Integration pattern is not appropriate for your development efforts, review the Business patterns to determine which pattern best addresses your e-business needs.