Programming Guide - Actian

External ClassesThis script first sets a value for the BonusTemp attribute and then invokes itssuperclass's version of the method. The Manager class's superclass,PermanentEmployee, also invokes the Hire method defined by its superclass,Employee. The SendSuperclass method in this script, therefore, has the effectof superseding the Hire method all the way up the hierarchy.The SendSuperclass method is effective even if the immediate superclass doesnot define the method being superseded. For example, assume that thePermanentEmployee class did not define its own version of the Hire method,but its subclass, Manager, needs to supersede the version defined at the top ofthe hierarchy for the Employee class.In this case, invoking the SendSuperclass method in the Hire method forManager automatically invokes the current method as it was defined byEmployee. The Manager class's script does not need to specify that it issuperseding the method defined for Employee.For the complete method scripts of the user classes discussed, see the userclass components in the online Videos application.External ClassesAn external class defines the class properties, methods, and events for one ormore external objects. An external class provides a wrapper for a singleexternal object so that OpenROAD can use it seamlessly in your application.This wrapper provides display and storage space for the external object in yourOpenROAD application. For instance, it allows a spreadsheet, word processor,or other application to be used within an OpenROAD application. OpenROADcan use a Microsoft Excel spreadsheet as an external object, read data from it,and use the data in OpenROAD code.ActiveX SupportExternal classes let you use ActiveX controls and ActiveX automation in yourOpenROAD applications.ActiveX objects have properties, methods, and events just like other classobjects. Therefore, they are treated as external classes in OpenROAD. Eachunique ActiveX object used in OpenROAD must have an external class torepresent it. The external class is viewed by OpenROAD as an actual systemclass. As such, external classes can be displayed and manipulated like anyother class in the system.For more information about ActiveX, see the documentation supplied with theActiveX object.Working with Classes 135