How HATS engine works?

How HATS engine works?

HATS is an IBM Rational tool that transforms IBM 5250, 3270 and VT green screen applications to web applications. To understand better how HATS engine internally works we need to see what “HATS screen recognition criteria” is.

HATS uses screen recognition criteria to match host screens. Host screens can be recognized by HATS engine through any criteria, for example total fields are on the screen, cursor coordinates, and specific text strings on the screen at a defined place or anywhere on the screen. When a host shows a screen, HATS engine picks it and searches to see whether the current screen matches any of the defined screen recognition criteria within the project. If HATS engine catches a match, the programmed actions for the screen customization are executed.

Following diagram illustrates the flow, how HATS engine performs the transformation.


Host shows a screen, HATS performs a comparison among screen recognition criterion defined in the project, this is done in the order defined by project’s event priority.
When a match is found, HATS performs the specified actions for the recognized screen customization, these actions may include,

  • Application of a transformation
  • Execution of business logic
  • Interaction with global variables
  • Forwarding to a URL
  • Playing a specific macro.

If there is no matching screen recognition criteria for the host screen, HATS processes an event designed for unmatched screens. The default action of this unmatched event is to show the host screen by the default transformation and only applying the project’s default template, this creates a webpage on the fly using the text and fields present on host screen.

As the 5250/3270 host displays new screen, HATS initiates with all these steps again and proceeds through these the each step.

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About Asif Hussain

In the software industry from 2002, having experience in design, development, and analysis of enterprise software products, project management and public speaking.

Handled dozens of e-commerce web projects. Involved in development and implementation of financial applications and online stock trading platforms for banks and brokerage houses. Also worked on projects for Oil & Gas Marketing companies and Car Tracker systems.

Specializes in Enterprise Application Modernization, Islamic Murabaha / Margin Financing solutions, Portfolio management, Trade Settlement, and Online Stock Trading Engines.

Have worked as lead implementer for Customer Relationship Management systems (Oracle's Siebel CRM on demand & Sugar CRM).

Also have worked as lead analyst, project manager, and data migration expert for huge projects in government sector.

Currently working as 'Project Manager', Trainer and Senior Consultant, IBM Rational Enterprise Modernization' using IBM Rational HATS/HOD for Royal Cyber projects worldwide.

I am an MBA(Marketing) from College of Business Management(CBM/IoBM). Prior to that, graduated in Computer Engineering from Bahria University.

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