Object-Oriented COBOL?

Senior Seminar Sp. 2007Trevor Simpson

Object-Oriented COBOL?

• Why the “?”

• Isn’t COBOL dead

COBOL = Lazarus

• Created in 1959

• First standard finalized by ANSI in 1960

• Latest of 4 major revisions is COBOL 2002

COBOL Background

• Procedural Language

• Tightly Structured

• Strongly Typed

• Extremely Stable

• Highly Secure

• Batch Processing

Procedural vs. Object-Oriented

• Like a recipe• Everything done in

order• Functions• Modules• Call• Variable

• Like life• Different “objects”

interacting• Methods• Objects• Message• Member

The Object-Oriented Paradigm

• 4 main tenets – Inheritance

• Dog IS AIS A Animal

– Abstraction• Hide details of implementation

– Polymorphism• Determine exact method implementation at run-time• I.e. method or operator overloading

– Encapsulation• Data and Methods in ONE location

ANSI 85 Standard COBOL

• Columnar Restrictions– Cols. 1-6 Reserved for sequence #’s– Col. 7 Reserved for special character– Cols. 8-72 usable, anything beyond 72 ignored– Other restrictions on where Names and Type

definitions can start

ANSI 85 Standard COBOL

• 4 Divisions– Identification Division– Environment Division– Data Division– Procedure Division

ANSI 85 COBOL Example

• Assign2.CBL

• Report

ANSI 2002 COBOL Standard

• Latest Revision Adds Several Features– Boolean Data Type– Recursion– Compiler Directive for Free Format– Inline Comment “*>”– Support for Object Oriented Paradigm

2002 COBOL OO Elements

• Factory– Basically a separate set of code used to

handle general object tasks.

• Class, Object Keywords

• Interfaces

• Inherits Keyword

• Parameterized Classes (Like a Java Interface Class)

2002 COBOL OO Elements

• Usage Object Reference Clause– Perhaps most powerful OO element added– Allows dataname to be a reference(pointer)– Call Object Handles– Dataname can be set to refer to a specific

object type or be set to universal

OO COBOL Examples

• Driver Student

• COBOL with VB GUI

• COBOL Using XML

COBOL’s Future

• Estimates as high as 200 Billion lines of code• New standard creation underway for release in

2008.• Add support for specific collection classes

– SortedCollections– KeyedCollections– OrderedCollections

• Even touted as better way to learn OO principles

References

• Arranga, Edmund C. (1996). Object-Oriented COBOL. New York : SIGS Books & Multimedia

• COBOL Standards. (n.d.) Various pages from www.cobolstandards.com• Flint, E. S. (1997). The COBOL jigsaw puzzle: fitting object-oriented and legacy

applications together. IBM Systems Journal, 36(1), pp 49-65. Retrieved March 10, 2007 from Wilson Database.

• Glass, Robert L. (1997). Cobol--a contradiction and an enigma. Association for Computing Machinery. Communications of the ACM 40(9) pp 11-14. Retrieved March 3, 2007 from ABI/Inform Database.

• Hardgrave, Bill C. (Mar/Apr 2000). Cobol in an Object-Oriented World: A Learning Perspective. IEEE Software, 17(2), pp 26. Retrieved March 10, 2007 from Academic Search Elite Database.

• Native COBOL Syntax for XML Support. (Mar 30, 2006). WG4 N0248 TDR24716. Retrieved March 20, 2007 from http://www.cobolstandard.info/wg4/document.html

• Sammet, Jean E. (1985). Brief Summary of the Early History of COBOL. Annals of the History of Computing 7(4) pp 288. Retrieved March 3, 2007 from ABI/Inform Database.

• Sokol, Marc. (1990). Reader Viewpoint: Why 4GLs Cannot Kill COBOL. Journal of Systems Management, 41(5) pp 35-37. Retrieved March 13, 2007 from ABI/Inform Database.

QUESTIONS???