A Natural Web Front End using CICS Transaction Gateway

11/19/15
A Natural Web Front End using
CICS Transaction Gateway
Michael Erichsen, CSC
GSE Nordic and UK CICS Conference
Hursley, May 1999
Session N25

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Agenda
 CSC
 Covering Students’ Living Costs
 The US2000 Project
 A three Tier Architecture
 Three different views of Data
 The Program Flow
 Java Development
 Other Challenges

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CSC
 A “Collection of Small Companies” - 51,000 employees

Management Consulting

Systems Integration & IT Consulting

Technology Management
 CSC Scandinavia

CSC Denmark

CSC Computer Management

CSC Sweden

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Agenda
Covering Students’ Living Costs

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Covering Students’ Living Costs
 SU (Statens Uddannelsesstøtte) is the Danish State
Education Grants and Loan Scheme Agency
 Provides for 250,000 students every year
 Tuition is free at public and most private educational
institutions
 Supports students with grants and loans
 Annual budget over 8,000,000,000 DKK - 0.6% of GNP

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Agenda
The US2000 Project

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The US2000 Project
 The current system consists of 70+ 3270 applications
running Software AG Natural and Adabas on CICS/VSE
 The Agency decided in 1997 to modernise system
 Asked three partners for proposals November 1997
 A technical model was prepared by CSC in May 1998
 Specification made in June 1998
 CSC on project July 1998
 Pilot production 2Q 1999
 Full implementation 4Q 1999

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Why a Web Interface?
 A modern graphical user interface
 Safeguard the investment in business logic
 Maintain a stable environment
 Easier to learn for new users
 Can cooperate with PC environment
 Relieve the Agency of the responsibility for the users’
network connections and software distribution
 Enabling self service by students

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Agenda
A Three Tier Architecture

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PC UNIX Server VSE
WEB
Browser
CICS Client
CICS
Gateway
for Java
WEB Server
VTAM
CICS
Natural
HTTP
APPC
ADABAS
Personal
Comm
A Three Tier Architecture

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The Communication Architecture
 A classic Windows Client/server model was rejected due
to configuration and software distribution problems
 A general transaction format is designed to simplify
programming
 Application logic in Client and on CICS/VSE, not on
middle tier
 Fundamentally just a new incarnation of the well-tested,
rock-solid transaction processing model

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Why a Middle Tier?
 CICS/VSE has no direct Web interface - yet
 Design prepared for interfacing directly with CICS
 Two different proposals:

SAG Entire Broker

 The Agency bought a complete IBM package with
RS/6000, AIX, LDGWS, and CICS Transaction Gateway
for the middle tier

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The Server Architecture
 Total separation of user dialogue from business logic
and data access
 Natural programmers can concentrate on business logic
 Willing to reprogram 3270 applications to server
programs
 Prepare architecture for the future
 Two simple CICS Assembler programs make up server
end of "Pipeline"

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The NATCALL Interface

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The Client Architecture
 Visual classes
 Formatting classes
 Transaction classes
 The architecture has matured through three steps to
Client heaven

Step 1: The decision to use Java

Step 2: Applets or Applications

Step 3: Java Beans

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Step 1: The Decision to use Java
 Better function than plain HTML
 Enables mouseless operation
 Java Applets are easy to distribute on-line
 Response time proves acceptable

Averaging 0.5 seconds on browser

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Step 2: Applets or Applications
 Applications run Stand-alone on the desktop
 Applets run inside a browser
 Problems with caching of jar files
 Browsers are not compatible
 Applications can also be distributed on-line
 But loses some functionality

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Step 3: Java Beans
 Java Beans is a component technology
 Helps to design for code reuse
 Visual builder tools understands the components
 Systems programmers can encapsulate complexities
and validation in Java Beans
 Application programmers can concentrate on user
interfaces
 Both applets and applications can be built from Java
Beans

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Agenda
Three Different Views of Data

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Three Different Views of Data
 Java classes

Internal fields/properties with names and types

Accessed through "setter" and "getter" methods
 CICS Program

One long buffer (Commarea) with an implicit structure

Each end must understand offsets, lengths and types
 Natural Programs

Positional parameters with names and types

Accessed by name

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How to Map a Commarea?
 Different models

Self describing format

Variable length fields

Predefined structure known by both ends

...
 Characters only or binary numeric data?

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Predefined Transaction Format
SSeeggmmeenntt UUsseedd bbyy CCoonntteennttss
A Pipeline only Password
Natural and
Adabas identifiers
Internal response
time
B Pipeline
Natural Control
Userid
Error information
C Natural Control
Server Programs
Personal ID No.
Response text
Journal
information
D Specific Server
Program only
Transaction
specific fields

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Data Inversions
SSuubbssyysstteemm DDaattaa vviieewweedd aass DDaattaa aacccceesssseedd bbyy
Client front-end Visual fields Getters and
setters
Client back-end Bean Properties Getters and
setters
Pipeline Data buffer -
Natural programs Positional
parameters
Name

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Agenda
The Program Flow

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PC UNIX
Server
VSE
Java
Client
CICS
Transaction
Gateway
ADABAS
The Program Flow
Front
end
Back
end
Boot
strap
Control
Server

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The US2000 Java Client

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Formatting Beans
A M O U N T _ N 8
B e a n
D D _ M M _ Y Y Y Y
B e a n
C P R N R
B e a n
E t c .
N a t u r a lF o r m a t e r in g
( A b s t r a c t )
C o m p o n e n t
O b je c t

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Transaction Beans
D is p la y S t u d e n t I n fo r m a t io n
B e a n
D is p la y P a r e n t I n c o m e
B e a n
E t c .
C s c A b s t r a c t T r a n s a c t io n
O b je c t

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Front-ending Natural
TS Queue

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3GL Front End on CICS
 Distributed Program Link with a Commarea from CICS
Client through APPC
 Saves Commarea in a Temporary Storage queue
 Saves User id, response time etc. in a Data Table for
surveillance and performance monitoring
 Links to Natural Boot Strap with a list of dynamic
parameters including data from the A and B segments

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Natural Boot Strap Program
 Does Natural initialisation and housekeeping behind the
covers
 Cannot be called with data
 Calls out again to another 3GL program
 Just two lines of code

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3GL Back End on CICS
 Reads the Commarea from Temporary Storage
 Allocates extra storage for communication between
Natural subprograms to prevent storage violations
 Calls Natural Parameter List Builder Program
 Calls Natural Control Subprogram with Commarea as a
single positional parameter
 Afterwards data is returned through Temporary Storage
 A dummy back end seems to be necessary to get
around Natural’s Menu system...

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Natural Subprograms
 Natural Control Subprogram

Subdivides the Commarea into positional parameters

Gives control to the appropriate server subprogram

Saves response time returned from the Client

Assembles data from server subprogram back into a single
positional parameter
 Natural Server Subprogram

Validates data

Does business logic

Accesses Adabas

Eventually about 100 server programs with as many
different D segments

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Agenda
Java Development

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Java Development
 Objects, reuse, and components
 Division of work
 Education
 Designing the component architecture
 Visual builder tools and how to choose them

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Objects, Reuse, and Components
 Object technology still hasn’t fulfilled the promises of
code reuse
 Have to consciously build code reuse into the design of
classes and applications
 Components can help doing this
 Supported by a new generation visual builders
 Need to organise the project group division of work
 Need to adopt an iterative development process

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Division of Work
 Visual application programmers

User interface
 Systems programmers

Communication

Complex technical matters
 Tools for each kind of person
 Optimal use of differentiated qualifications and interests
 Make it fun for everybody to ensure motivation and to
reduce staff turnover

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Education
 Java is difficult to learn for a Natural or 3GL developer

Objects is a different ballgame than structured (or even
unstructured) programming

Components are something else again
 Three distinct education needs

User interface design

Object design

Using the specific tool

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Designing the Component Architecture
 Generalise common functionality into abstract parent
classes

Secures optimal reuse of code

Concrete, derived classes only contain what is specific to
them
 An iterative development process

Continuous identification of functions to be moved from
application to systems programming
 Keep classes small and simple

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Visual Builder Tools
 Visual Café from Symantec
 Visual Age from IBM
 More than 20 others
 Started with Visual Café 2.5
 Changed to Visual Age 2.0

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Criteria for Visual Builder Choice
 Import/export of source
 Support for the preferred division of work
 Support for programming styles and services
 External support

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Keeping Java classes in Sync
with Natural Development

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Natural in - Java out
16:23:44 Subprogram ISTA Library U
0010 ************************************
0020 * PROGRAM : ISTA
0030 * FUNKTION : Stamoplysninger
0040 * BESKRIVELSE : Viser stamoplysnin
0050 * støtteår.
0060 * Programmør : Finn Jørgensen
0070 * OPRETTET : 16-12-1998
0080 ************************************
0090 * Versionsændringer:
0100 *
0110 * Version Init Dato Beskrivelse
0120 * ------- ---- -------- ------------
0130 * 001 FJ 16-12-98 VERSION 1.
0140 ************************************
0150 DEFINE DATA PARAMETER
0160 *
0170 USING A-PARMTR
0180 *
0190 LOCAL USING T-PERSON
0200 LOCAL USING T-REKVIS
0210 *
package dk.su.us2000.trans;
import java.beans.*;
import com.sun.java.swing.*;
/*** This class represents the commarea b
* It is generated by the CSC Commarea Ge
* <p>This class contains accessors and m
* in the D segment of the transaction de
* It inherits accessors and mutators
* for the A, B, and C segments from its
* @version Natural: 981216 16:23, Java:
* @author Finn Jørgensen
*/
public class ISTA extends dk.su.us2000.tr
/** No-arg constructor
*/
public ISTA() {
super();
initialize();
} // No-arg c:tor
/** Gets the VERSION property (String) va
* @return The VERSION field.
* @see #setVERSION
*/
public String getVERSION() {
byte[] ba = new byte[3];
System.arraycopy(commarea, 830, ba, 0, 3)
String sout = new String(ba);
if (isDebug()) {
System.out.println("Method getVERS
} // if debug
return strip(sout, "N");
} // getVERSION()

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Properties of a Generated Transaction Bean

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Agenda
Other Challenges

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State Handling
 CICS pseudo transactions have states - web
transactions are stateless
 User can go away without telling CICS
 Retaining sign-on between calls
 Achieving update integrity by serialisation using
timestamps on each database record

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New Version Problems on Old Bottles
 Web distribution solves the old version problems
 But the most common browsers do not implement Java
identically

Can be remedied by using the Java Plug-In
 Still have to handle a multitude of version
interdependencies and incompatibilities

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Security
 Logon is done with userid and password and is
validated by Natural Security
 A user profile is retrieved from Adabas and sent to the
Client to control the dynamic menu
 Security of userids, passwords, and data when running
on the open network is currently being analysed

A Natural Web Front End using CICS Transaction Gateway

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