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IBM Software Group / DB2 Information Management

© 2005 IBM Corporation

Informix 4GL and EGL

Jerry Keesee, Director of the Informix labS. Venkatesh Gopal, Development, Informix R&D


© 2005 IBM Corporation2 February 2, 2005

Disclosure Information

PLANS ARE SUBJECT TO CHANGE OR CANCELLATION WITHOUT NOTICE



Agenda

Informix 4GL Today

Why EGL?

Overview of some EGL capabilities

4GL / EGL Syntax Comparison

JSF & EGL – Web Application Development Overview

Conversion of 4GL to EGL



Current I4GL Development/Runtime Environment

A well established development environment.

Can be deployed as either pseudo-code (P code) or C code applications– P code primarily is used for development – debugger works with P

code only– most develop with P code and deploy with C code

Connectivity to Informix database servers only– unless an Informix Gateway server is added

Small disk/memory footprint delivers very good runtime performance

Wide platform coverage.



Primary Requirements for I4GL

Provide application database connectivity to IDS & DB2

Provide a modern integrated development environment

Provide the capability to create modern applications with:

– graphical user interfaces

– and character-based user interfaces

Maintain and grow user base

– enhancements should “fit” existing users

– and be compelling for new ones…



EGL

A language as easy as I4GL to use and develop with.

Provides an industry standard IDE (Rational Application developer) for developing EGL, Java, Web and COBOL applications.

Provides an enriched set of the same capabilities.

– Text user interface (Curses based).

– Calls to “C” functions.

– SQL (embedded, dynamic and more).

– Interactive debugging capability.

– Powerful reporting capability.

– Command line based application development.

– Data types (all of I4GL and some more in addition).



EGL .....

In addition to the I4GL feature set provides

– Development and runtime capabilities for Windows platforms.

– More general programming capabilities.

– Web Application development and deployment.• Same business logic can be shared in both deployments.

– Multiple Database connectivity.• Uses JDBC and allows to connect to any DB.

– Service Oriented Architecture (Web Services).

– MQ Access.

– File I/O

– Provides for COBOL generation options (deployable in i-Series and z-Series).

– Calling out Java code from EGL.

– and more…



EGL (similarities to I4GL).

Lots of similarities.

– Basic statements and looping constructs are similar.

– SQL statements are similar to 4GL (prepare, execute, open, get (fetch), close and for each).

– Text user interface similar (with a more general programming model) to I4GL with extended capabilities.

– Reporting framework provides for a wider set of output formats (PDF, Text, XML, CSV, HTML).

– A highly interactive and visual debugging environment based on the Eclipse framework.



Examples (Comparing I4GL to EGL).

DEFINE INTVAL INTEGER

DEFINE myRecord RECORD

intval INTEGER,

floatval FLOAT,

decimalval DECIMAL

END RECORD

LET intval = 10

LET myrecord.intval = 10

CALL funcName(param1,param2)

INTVAL INT;

Record myRecordType

intval int;

floatval float;

decimalval decimal;

End

myRecord myRecordType;

myotherRecord myRecordType;

intval = 10;

myRecord.intval = 10;

funcName(param1,param2);



Examples (Comparing I4GL to EGL).while(i < 10)

let i = i + 1

end while

case (i)

when 10

…

when 20

…

otherwise

…

End case

while(i < 10)

i = i+1;

End

case(i)

when (10)

…

when (20)

…

otherwise

…

end



Examples (SQL in I4GL compared to EGL)

insert into mytable (code, quantity) values (‘abc’, 10)

prepare stmtid from "select fname,lname from customer where customer_num=10"

declare secondSet cursor for select fname,lname from customer

open secondSet

fetch secondset into fname,lname;

execute #sql{

insert into mytable(code,quantity) values('abc',10)};

prepare stmtid from "select fname,lname from customer where customer_num=10";

open secondSet

with

#sql{select fname,lname from customer };

get next from secondSet into fname,lname;



Some Infrastructure differences…

EGL being IDE based requires knowledge of Eclipse Workspace paradigms.

Everything exists in a workspace– Workspace has projects.

• Projects have packages.– Packages have files.– Files can be either EGL source files, EGL programs or EGL libraries.

A program is equivalent to a I4GL file having the main function.

A library is equivalent to any I4GL modules that provides functions for use by other I4GL modules or I4GL globals file.



FUNCTION compute_BA(at_bats, hits) DEFINE at_bats INTEGER DEFINE hits INTEGER DEFINE BA DECIMAL (4,3)

LET BA = hits/at_bats RETURN BAEND FUNCTION

IDS

PACKAGE PlayerStatsApplication;

import InfxDbSchema.sports.stats.*;

PROGRAM player_mainuse player_ba;

player_bats rec_like_informix_atbats; batting_ave rec_like_informix_battingaverage; FUNCTION main()

BA DECIMAL (4,3);

PREPARE $_STMT_curs_at_bats FROM "select * from informix.atbats";

open curs_at_bats with $_STMT_curs_at_bats;

WHILE (SQLCODE = 0)

get next from curs_at_bats into player_bats.lname, player_bats.atbats, player_bats.hits, player_bats.walks; IF (SQLCODE = 100) EXIT WHILE; END BA = compute_BA(player_bats.atbats, player_bats.hits);

execute #sql{INSERT INTO informix.battingaverage VALUES (:player_bats.lname, :BA) }; END //WHILE commit() ; CLOSE curs_at_bats;END // FUNCTION

END // PROGRAM

PACKAGE PlayerStatsApplication;

LIBRARY player_ba

FUNCTION compute_BA(at_bats INT IN, hits INT IN) returns (DECIMAL (4,3))

BA DECIMAL (4,3); BA = hits/at_bats; RETURN( BA); END // FUNCTION

END // LIBRARY

Informix 4GL TodayInformix 4GL Today EGL TodayEGL Today

DATABASE stats

GLOBALS DEFINE player_bats RECORD LIKE informix.atbats.* DEFINE batting_ave RECORD LIKE informix.battingaverage.*END GLOBALS------------------------------------------MAIN------------------------------------------ DEFINE BA DECIMAL (4,3) DECLARE curs_at_bats cursor for select * from informix.atbats OPEN curs_at_bats WHILE (SQLCA.SQLCODE = 0) FETCH curs_at_bats into player_bats.* IF (SQLCA.SQLCODE = 100) THEN EXIT WHILE END IF CALL compute_BA(player_bats.atbats, player_bats.hits) RETURNING BA INSERT INTO informix.battingaverage VALUES (player_bats.lname, BA); END WHILE COMMIT WORK CLOSE curs_at_batsEND MAIN



Compiling and running applications.

Set up the compilation options in the build descriptor.

Generate to Java

Run the application.

Take the generate Java and deploy it to any other machine with the runtime libraries.

If you have created a web application, deploy the web archives to the test server or any J2EE server from within the IDE.



Some extended capabilities…



Integrated development environment

An industry standard IDE

Based on the Eclipse framework

Provides for different development perspectives– EGL– EGL/Web – Java and more.

Context Sensitive editor

Debugging capability (Interpretive debugger).

Page designer for JSPs and page handlers.

Code Assist (using Ctrl + Space)



Records

Different types…– Basic Records

– SQL Records

– Serial Records

– Indexed Records

– MQ Records.

Record type identifies the I/O that can be done

Same statements are used for different Record types

No I/O with Basic records.



Records

Operation Serial SQL Indexed MQ

addinsert record at end

of fileInsert record insert record at key

send record to queue

close close file close file close file close queue

delete n/adelete current

recorddelete current

recordn/a

get (key) n/arecord based on

keyrecord based on

keyn/a

get next get next record get next record get next record get next message

get previous n/a get previous record get previous record n/a

replace n/areplace current

recordreplace current

recordn/a



Records (SQL Records)

Record definitionRecord CustomerRecord type SQLRecord {tableNames=("customer") }

customer_num int {column=customer_num};

fname char(15) {column = fname};

lname char(15) {column = lname};

company char(20) {column = company};

address1 char(20) {column = address1};

address2 char(20) {column = address2};

city char(15) {column = city};

state char(2) {column = state};

zipcode char(5) {column = zipcode};

phone char(18) {column = phone};

end

A default SQL statement is generated for every SQLRecord

The SQL column information can be extracted using the IDE.



SQL Records (example)mycustomer CustomerRecord;

myCustomerArray customerRecord[];

open resultSet for mycustomer;

try

while(sqlcode = 0)

get next from resultSet;

//mycustomer.customer_num has the value.

if(sqlcode = 100)

exit while;

end

end

onException

End

get myCustomerArray;



File I/O using Records

Create a serialRecord.Record FileRecord type serialRecord {filename="customer"}

customer_num num(10);fname char(15);lname char(15);

End

Create a Resource Association.

Write your code.myfilerecord FileRecord;

myfilerecord.customer_num = 100;

myfilerecord.fname = “John”;

myfilerecord.lname = “Doe”;

add myfilerecord;



Message Queue Access

Easy MQ handling.– Create Record definitions.

Record myMQRecord type MQRecord { queueName = "mqRA" }fname char(10);lname char(10);

End– Create a Resource Association between the queueName attribute and the MQ system.– Write your code.

mqr myMQRecord;mqr.fname="Venkatesh";mqr.lname="Gopal";add mqr;

get mqr;

– Take full advantage using a package called “MQReusableParts”, a part of your standard distribution.



Web Development with EGL.

Sun PetStore Reference Application:

Hand-Coded in Java IDE MDD Competitor

WebSphere StudioJSF & EGL*

507.5 Hours 330 Hours 55 Hours

*Internal Study



Web Development using JSF

JSF is a J2EE Web UI / programming framework

User interface component model - Set of standard widgets

Specification allows creation of custom UI components

Event handlers to process client-driven events

Actions to call business logic

Validation framework to allow server side validation

Internationalization/Localization



How do JSF and EGL fit together?

JSF

Servlet

(Faces Servlet)

JSP

(View)

Request

Response

Invokes

Controller

EGL

EGL

EGL

Model



How do JSF and EGL fit together?

A perspective (EGL Web) that allows users to create a view (JSP) containing standard controls and widgets.

Easy Drag and Drop to bind the data components to presentation items in the view.

Automatic creation of a page handler that implements the controller

– Has an onPageLoad function, which is invoked the first time the web page is rendered.

– A set of event handlers, each of which is invoked in response to a specific user action (like clicking on a button or a link).

– Validation functions to validate web-page input fields.

Page handler can call other EGL library functions that implement the actual business logic.

Data can be passed between pages using simple EGL statements.



Taking your applications from 4GL to EGL



What is the Conversion Strategy?

Goal is to convert an I4GL application to the equivalent EGL application that uses:– the same display device– the same database server– I4GL TUI applications will be converted to EGL TUI applications

Convert, on a program-by-program basis, using the conversion utilities:– provided as part of the IDE– also available from the command line

Separate conversion passes required for:– database metadata extraction– shared libraries (C code or combination of C and I4GL code)– I4GL source code

Automated conversion should convert most 4GL source code– but, some 4GL programs may require manual intervention



Conversion Assumptions

I4GL code is “legal”– it will compile with I4GL 7.32 compiler

– conversion will not “fix” invalid I4GL code

Multiple passes are required

Functions that can not be resolved during conversion are assumed to be C code functions– if function is later found to be an I4GL function, re-conversion

would be required

C code functions do not use undocumented I4GL internal functions



How is this Going to be Done?

WebSphere Studio conversion plug-in– runs within the EGL development environment (Windows or

Linux)• I4GL source directories can be mounted from current environments• or copied to the EGL development environment

– GUI wizard collects information about I4GL source environment:• I4GL source and EGL destination directories• I4GL source files (.4gl, .per, .c, .so, message files, etc)• database connection information• locale information

– generates configuration XML files

– invokes the conversion utility• displays conversion log upon completion



How is this Going to be Done?

Command line conversion utility

– Java program can be run in current I4GL build environments

• perhaps via current makefiles

– requires XML configuration file describing current 4GL environment:

• could be generated using the IDE plugin

• or generated via shell script

– generates EGL conversion “projects” containing

• database meta data

• makefiles to re-link C code with new EGL stack library

• EGL source files

• report designs and other reporting artifacts



Conversion Artifacts

Configuration file

– XML file generated from interaction with conversion wizard

– contains required conversion project information

Manifest file

– XML file generated during conversion of shared libraries

– contains declaration and usage information about each of the functions (C and I4GL) used in the shared library

– used to resolve function declarations in dependent I4GL shared libraries

– required for subsequent I4GL source code conversions

Log file

– contains warnings and errors

– status of each source file

– summary of conversion



Order of Conversion is Important!

Database metadata– conversion creates EGL packages for each database used in

the project

– schema metadata will become a separate EGL project which can be referenced by other EGL projects

Shared libraries– conversion generates Manifest file and makefile

I4GL source files– .4gl files

– .per (form) files

– message files



Pre-Conversion Tasks Identify & locate all the components of the 4GL

application to be converted– (.4gl, .per, message files, shared libraries)

Identify connection information for each database used

Start Informix database instances

Mount/copy source code to EGL development machine, if required

Determine destination directory for converted EGL source code & conversion artifacts

Identify “Client” locale – used to convert message files



Conversion Utility Processing

Map all I4GL constructs into equivalent EGL constructs

Convert existing “.4gl” source files into “.egl” source files

Convert existing “.per” form specification files into “.egl” TUI specification files– No special file extensions for EGL form definitions

Migrate existing I4GL error message files into EGL error messages

Convert existing I4GL reporting logic into equivalent EGL reporting logic

Generate a “makefile” that will be used to link the C shared libraries to the converted EGL project – makefile will have targets for different operating systems

Report all warnings and errors

Generate log file to indicate the status of conversion

Create default EGL build descriptor file for the project



Conversion tool within the IDE….



Conversion tool…



Conversion tool….



Conversion tool (artifacts)…



Conversion tool (conversion log).



Post-Conversion Tasks

Review log file

Fix identified problems

– on the 4GL side and re-convert or

– in the new EGL file

– shared libraries may have to be re-converted if functions cannot be resolved

Open the project in the IDE

Verify EGL packages and source files

View/update EGL build descriptor file

“Generate” Java code for the project

– fix problems in the EGL code

Set runtime properties from existing environment variables

Launch new EGL project



Conversion Limitations

Database connections cannot be shared between EGL and C code

C code cannot call EGL functions

Default values set in syscolval table are not accessed

I4GL Dynamic Arrays (7.32 release) will not be converted in initial release



main.4gl

BL

inventory.4gl

BL

catalog.4gl

BL

BL

IDSText

Reports

c_code.so

C functions

main.egl

BL

inventory.egl

BL

catalog.egl

BL

BLSchemaLib.egl

c_code.so

C functionsText

Reports

I4GL to EGL Conversion

Typical I4GL Program … Becomes Typical EGL Program

form.per

form.egl



IDSDB2

main.egl

BL

inventory.egl

BL

catalog.egl

BL

BL

SchemaLib.egl c_code.so

C functions

Text

Reports

PDF Output

HTML Output

XML Output

Webmain.egl

Webinventory.egl

Use your I4GL Business

Logic in EGL Web Services

Use your I4GL Business Logic with Message Queues

Use your I4GL Business Logic

in whatever comes next!!!

Now What Can You Do With It …



EGL Releases…

6.0 ega 12/3/2004, GA 1/7

fix001 ega 12/20/2004 (first release for Informix)

ifix003 ega 2/28/2005 (Release with conversion tool available through Rational updater).

6.0.0.1 ega 4/8/2005 (Conversion tool available through Rational updater)



EGL information

EGL site

http://www-128.ibm.com/developerworks/rational/products/egl/

EGL downloads

http://www-106.ibm.com/developerworks/rational/library/egldoc.html



http://www.ibm.com/software/data/informix

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Documents

egl capabilities

egl similarities

egl programs

egl libraries

bats integer

i4gl file

ba decimal

bats record