Object Oriented Cobol

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Welcome to this short introduction to Object Oriented Cobol.
Let’s start off by acknowledging the person who led the way.

There are over 400 warships in the US Navy…
Only two of them are named in honor of a woman
One of them is named the USS Hopper

The NERSC (National Energy Research Scientific Computing Center) first
Cray XE6 petaflop supercomputer is named Hopper

Rear Admiral Grace Murray Hopper
(December 9, 1906 – January 1, 1992)
She was a champion
for increasing the
usability of computers,
understanding that
their power and reach
would be limited
unless they were made
to be more user
friendly.
Grace Hopper, was a
pioneer in the field of
software development and
programming languages
and the creator of the first
compiler.

2002 – ISO COBOL-2002 (OOC)
1959 – Short Range Committee - COBOL-60
1968 – American National Standards Institute – ANSI COBOL-68
1974 – ANSI COBOL-74
1985 – ANSI COBOL-85
1997 – ISO (Committee Draft) Draft – Object Oriented Cobol
Grace Hopper pioneered the implementation of standards for computer systems

From the ISO 2002 Cobol standard

a
compute a = b + c
b c
Cobol program - A simple program
Entry point
Variables
Procedure
Program
One program entry point
One common memory

Cobol program – Multi-procedural
One program entry point
One common memory for all procedures
a
compute a = b + c
b c d
compute d = e + f
e f
Entry point 1 Procedure 1 Procedure n Entry point n
Variables pnVariables p1
Program

a
compute a = b + c
b c d
compute d = e + f
e f
The analogy in Object Oriented Cobol
Entry point 1 Procedure 1 Procedure n
Each procedure has its own entry point
Each procedure has its own memory
Each procedure is invoked individually
Entry point n
Variables pnVariables p1
Program

Variables p1
a
compute a = b + c
b c d
compute d = e + f
e f
The OO-Cobol Class
Entry point 1 Method 1 Method n Entry point n
Variables pn
In Object Oriented Cobol, as in Java –
o a procedure is called “method”
o methods are defined in a “Class”
Class

OO-Cobol – Class
Write the Cobol source that defines the Class
a
compute a = b + c
b c
Method
Method
Variables
Class

OO-Cobol – Program invokes Class
Write the Cobol source of the Program that will use the Class
a
compute a = b + c
b c
Method
Method
Variables
Class
invoke method…
Program
Declare a reference to the Class in the program
The program can then invoke methods of the Class

For example
a
compute a = b + c
b c
Method
“COMPUTE_SALARY”
Method Variables
NAME
ID
DAILY_SALARY
Class
“Employee”
invoke method
COMPUTE_SALARY
Program
EMP_CALC
OO-Cobol – Program invokes Class

Class Definition
Class Variables
OO-Cobol – Defining a Class

Method – “new”
OO-Cobol – Class Methods
Just like a cookie cutter is used to create cookies, the Class serves as a
template for creating a live instance of itself – an object.
The “new” method creates the object that will be used by the program.

OO-Cobol – Class Methods
The “new” method giving us access to an object is similar to turning the
ignition key in a car – once we do so, we can use the functions that the car
has to offer: driving, braking, honking and so on.

Method - Compute
Method – Set
OO-Cobol – Examples of other Class Methods

Declaring the Class in the invoking program is analogous to
declaring a file in the INPUT-OUTPUT section
OO-Cobol – Referencing the Class

Defining the object to be used in the invoking program is analogous
to defining the file record in the FILE section
OO-Cobol – Defining the object

OO-Cobol – Example of invoking the “new” method

OO-Cobol – Example of invoking the “GET_NAME” method

OO-Cobol – Objects
Like putting a “new” coin in a slot machine “returns” a new ball to play with
each time, the program can work with a number of objects at the same time.

OO-Cobol – OO implementation
Encapsulation
Restricting access to an Object’s components
For example – Using method variables instead of global WORKING-STORAGE
Creating a sub-type of a Class while reusing its code and memory definition
Example – Defining a Class for computing salaries for Employees and Managers
Polymorphism
Inheritance
Invoking the same method name in different objects, different parameters
Example – “CALCULATE_SALARY” for both Manager and Employee

Class Definition - Inherits
Class Variables
OO-Cobol - Inheritance

Method Override – COMPUTE_SALARY

OO-Cobol – Java integration
Using Java Class String in an OO-Cobol program

Using JSON object

Send/Receive JSON data via Ajax with AngularJS client
Use hashmaps to store data
Define and use Java arrays (OCCURS DYNAMIC)
Define and use Java variable types such as String (PIC X ANY LENGTH)
Run as servlet under webserver using HTTP session
Monitor performance using standard Java performance tools
These are just a few of the possibilities that open up for you when you by
using Object Oriented Cobol – getting the best of both worlds

Thank you.
And one final word about Grace Hopper…

While she was working on a Mark II Computer at Harvard University in 1947, her
associates discovered a moth stuck in a relay and thereby impeding operation,
whereupon she remarked that they were "debugging" the system.
The remains of the moth can be found in the group's log book at the Smithsonian
Institution's National Museum of American History in Washington, D.C.

Object Oriented Cobol

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