At CODA we are heavily into the implementation of design patterns within our Java and .Net based products, and as such found ourselves quickly wanting to benefit from them on the Salesforce platform as we embarked on our CODA2go project to build a new Finance system. To date we have implemented Domain Model, Unit of Work, Identity Map, Lazy Load, Data Mapper and Service Layer. The platform also provides a solid implementation of the Model View Controller pattern through its new Visualforce technology. It’s very likely that CODA is amongst the first, if not the first software vendor to implement these patterns on this platform and I’m pleased to say despite the infancy of the Apex language they have taken very well. For those unfamiliar with design patterns, think of them as generic cook books for developers that describe solutions and strategies to building well structured and critically, well defined, consistent and thus maintainable implementations. This Wikipedia article is a good general reference. The above links are taken from Martin Fowler’s excellent site. Implementing these patterns alongside a representation of our product’s domain model has also been critical to our desire to keep code relating to aspects such as business logic, data representation, querying, persistence and user interface code separate. This approach has been base architecture design for all CODA products ever since our first client server application, CODA-Financials.