OpenL Tablets is an open source business rules management system that Exigen has been developing since 2004. It has the usual components – a rule engine, rule repository, web-based rule editing and management environment and a web services deployment front end. They also have a constraint engine (Constrainer) and a mapping framework (Mapper) for integration. The focus of OpenL Tablets is on allowing business analysts to create and manage business rules independently from a technical team. As such they support both web editing and an Excel format.
A variety of rule tables are supported – rule sheets, lookup tables, cross-reference decision tables and tables designed to represent decision trees (though these are a little awkward obviously as they are in a table). Documentation and more advanced formulae can be embedded in these tables using business expressions (however, Java 5 syntax can be also used by default). Human-readable versions of data elements defined in the domain model and any vocabulary are used in the rules for clarity. The overall flow of a decision is sequential and managed by tables themselves using nested calls to other tables. Algorithm tables can include loops and other programming constructs and other tables are used to manage the domain model as well as to define a vocabulary (allowed values for instance) and test data.
Rules are loaded up into the web environment from Excel – most customers will do initial rules development in Excel, then do a mix of online and Excel-based editing. Once in the web-based environment rules can be tested using test data, edited in the web environment or re-opened in Excel. Changes to the rules in the web editor are made directly to the Excel files and the file can be opened again to show all the changes as well as original documentation, layout etc.
Tables in the web editor can be set up to prevent overlaps or gaps in conditions and properties. Test cases can be defined and run online and test results are displayed showing which tests passed or failed. The decision tables involved can be accessed directly from the test results and each test can be traced using the logging features. Similarly compile or data errors are displayed inline and can be used to navigate directly to the table with an error. The web-based environment supports undo/revert, access to versioning/source code control, check-in/check-out, visualization of changes made, effective dates etc. The online environment supports deep linking to a specific table and the web editor can be embedded in other environments as a separate component.
Logging of rules fired is supported and changes can be applied to a running system. Deployment can be to a company’s own servers or to Exigen SaaS servers as REST or other services.
Future features include internationalization, database lookup for vocabulary and values, ACL security for access control and improvement in rule execution logs (specifically better access to them, replay and more details) plus support for Google Spreadsheets and Excel Live365.
Copyright © 2013 http://jtonedm.com James Taylor