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X 2.2 COBOL Class Definition Structure




X A COBOL class definition describes a class or a metaclass. A class
X definition constitutes a compilation unit.


X Class

X The entity that defines common behavior and implementation for zero,
X one, or more objects. The objects that share the same implementation
X are considered to be objects of the same class.


X Method

X Procedural code that defines one of the operations supported by an
X object, and that is executed by an INVOKE statement on that object.


X Instance Data

X Data defining the state of an object. The instance data introduced by
X a class is defined in the Working-Storage Section of the Data Division
X of the class definition. The state of an object also includes the
X state of the instance variables introduced by bases classes that are
X inherited by the current class. A separate copy of the instance data
X is created for each object instance.


X Subclass

X A class that inherits methods and instance data from another class.
X When two classes in an inheritance relationship are considered
X together, the subclass is the inheritor or inheriting class; the
X super-class is the inheritee or inherited class.


X Metaclass

X A special type of class whose instances are called class-objects.
X Class-objects are the run-time objects that represent SOM(R) classes.
X Any class descended from SOMClass is a metaclass.


X With the exception of the COPY and REPLACE statements and the END CLASS
X header, the statements, entries, paragraphs, and sections of a COBOL class
X definition are grouped into the following four divisions:


X The end of a COBOL class definition is indicated by the END CLASS header.


X Following is the format for the entries and statements that constitute a
X separately-compiled COBOL class definition.


 X  ___ Format--COBOL Class Definition _____________________________________ 
 X |                                                                        |
 X | >>__ _IDENTIFICATION DIVISION._ ___CLASS-ID.__class-name-1___._______> |
 X |     |_ID DIVISION._____________|                                       |
   |                                                                        |
 X | >__ _________________________________ _______________________________> |
 X |    |_identification-division-content_|                                 |
   |                                                                        |
 X | >___ENVIRONMENT DIVISION.__class-environment-division-content________> |
   |                                                                        |
 X | >__ _______________________________________________ _________________> |
 X |    |__DATA DIVISION.__class-data-division-content__|                   |
   |                                                                        |
 X | >__ __________________________________________________ ______________> |
 X |    |__PROCEDURE DIVISION.__ _______________________ __|                |
 X |                            | <___________________  |                   |
 X |                            |___method-definition_|_|                   |
   |                                                                        |
 X | >___END CLASS__class-name-1.________________________________________>< |
   |                                                                        |
   |________________________________________________________________________|

X END CLASS

X Specifies the end of a class definition.

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