IEEE SOFTWAREMarch/April 2001 - PDF document

IEEE SOFTWAREMarch/April 2001 ThoughtWorks higher-level tasks that did several of the in-sign principle thatÕs served mearate from everything else. ItÕs abut itÕs often not followed, whichmat it for display. A clearly separated piececlasses (based on your languageÕs organiz-the WIMPinterfaceÑwithout copying anycode from the WIMPinto the commandcomplexity. Any successful presentation re-line example, and also by writing a higher-Separating User InterfaceMartin Fowler March/April 2001IEEE SOFTWAREwithout porting, itÕs common to findfunctionality.Different screens often require sim-ilar validation logic, but when itÕsdling, itÕs difficult to spot. I remem-time, this was hyped as part of theand browser-based presentations, canto routines is far easier. Separating thetest. Testability is often ignored as ato modify.The difficultiesSo why donÕt programmers sepa-donÕt reveal the price for ignoringing WIMPinterfaces: Visual Basic,Delphi, Powerbuilder, and the like.putting WIMPinterfaces onto SQLmenu bound to a SQL query. Suchquickly build a WIMPinterface thattools donÕt provide any place to ex-ever, once domain logic gets compli-Web interfaces. If the domain logic isstuck inside a WIMPinterface, itÕsnot possible to use it from a Webbrowser.However, the Web interfaces of-code. To avoid this, make a separateWeb site, www.martinfowler.com, bybecome a bit of an XSLT whizÑandthe tools for that arenÕt even adoles-plain and follow. After all, whatprinciple isnÕt always easy to fol-low. I think itÕs a key principle inwell-engineered software. If we everMartin Fowleris the chief scientist for ThoughtWorks, anInternet systems delivery and consulting company. For a decade,in developing business information systems. HeÕs worked with Pulling away thedomain code alsomakes it easier tospotÑand avoidÑduplication in domain code.