This class is the parent for all IspecModel objects, and provides all the functionality of the system Ispec. The generated instances of IspecModel contain all the usage input, usage input/output, and usage inquiry fields from the corresponding Ispec. The IspecModel instances contain methods to:
Get and set the values of fields (known as getters and setters).
Enquire about the type and other properties of fields.
Establish listeners for VetoableChangeEvents and PropertyChangeEvents. These events notify interested parties when the value of a field is changed and can be used to invoke user-supplied validation code.