Parameterized classes

A parameterized class is a skeleton class definition that when passed the appropriate parameters will create a new class tailored to perform a given function. Parameterized classes allow developers to create classes that have common behavior. For example, a single parameterized collection class can be used to define many types of collection classes.

Example:   Let's consider container classes which are typically used to hold references to objects of a given class. In a banking application, a specific type of container class, say AccountCollection, could be used to hold the list of identifiers to each account object. To generate a collection class that is capable of holding or managing only identifiers of checking account objects, the class name CheckingAccount is specified as a parameter when the collection class is created.   Suppose AccountCollection is a parameterized class whose definition is given elsewhere. Part of its class definition is as follows:   CLASS-ID. AccountCollection INHERITS Base USING X. ENVIRONMENT DIVISION. CONFIGURATION SECTION. REPOSITORY. CLASS Base CLASS X. ....     In another source unit, the following would create a class which is a collection of checking accounts and an object reference for this new kind of class.   ENVIRONMENT DIVISION. CONFIGURATION SECTION. REPOSITORY. CLASS CheckingAccountCollection EXPANDS AccountCollection USING CheckingAccount. ... DATA DIVISION. WORKING-STORAGE SECTION. 01 a-checking-account-collection USAGE OBJECT REFERENCE CheckingAccountCollection. ...