Transcript Object-Oriented Programming and the Progress ABL Tomáš Kučera

Object-Oriented Programming and the
Progress ABL
Tomáš Kučera
Principal Solution Engineer / EMEA Power Team
> whoami
TKU
 Started with Progress Software Czech Republic –
Dec 19, 1994
 2 years @ Technical Support (1996 at ETSC)
 Since Dec 1996 – Consultant, Presales, Trainer,
Project Manager
 Currently – GFS Mgmt responsibilities for Cze&Pol,
Member of the EMEA Power Team – primary
responsibility for SAND
 Product Areas: OpenEdge, Sonic, some Apama and
Actional
 Contact: [email protected], Skype: tomas_kucera
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Agenda
 Obligatory Theory
 Simple Sample
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What are Objects?
 You interact with objects everyday
• A customer
• An order
• Your car
• The telephone
 All objects contains state and behavior
• What they can do and what changes when
they do
 Software objects represent these as:
• Data
• Methods
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( like 4GL variables )
( like 4GL procedures)
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Object-Oriented Principles
 Abstraction
• Break up complex problem
• Focus on public view, commonalities
 Encapsulation
• Hide implementation details
• Package data and methods together
 Hierarchies
• Build new objects by referencing or
extending other objects
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Object-Oriented Constructs
 Type
• Enforces type consistency at compile time
 Class
• Defines type with data and methods and
provides implementation
 Object
• Runtime instantiation of class
 Interface
• Defines type with only methods – no
implementation provided
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Why should I care about Object-Orientation?
Object-orientation’s big benefits
 Object-orientation is a highly structured way
to build applications
• Simpler modeling tool integration, e.g.
roundtrip engineering
 Code benefits
• Less bugs
• More reuse
 Business benefits
• Time to market
• Better maintainability
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Why should I care about Object-Orientation?
How do we get the benefits?
 Strong Typing
• Less runtime processing
• Improved quality through finding errors at
compile-time
• Class hierarchy known at compile-time
 Re-use
• Abstraction means code re-use
• Classes can be deployed for re-use
• Improved quality and higher productivity
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Unfortunately it is not totally free
 Requires more forethought than procedural
• Type hierarchies can be hard to change
– Refactoring and modeling can help
 Requires a base class library to get started
• Base classes can take a while to build
 Different mindset from procedural
• Easier, if you have worked with super
procedures before
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Object-Orientation versus Procedural
Procedural
 “Types” are created at
run-time
 Type definition is
loosely bound
 Inheritance is
determined at run-time
 Provides flexibility for
generic code
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OO
 Types are known at
compile time
 Type definition is
contractual
 Inheritance is set at
design-time
 Prevents run-time type
errors
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Mapping Procedures to Classes
Class
Procedure
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Procedure Files (.p)
Main block code
Internal Procedures
Functions
ON CLOSE
Super procedures
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Class Files (.cls)
Constructor
Void Methods
Method
Destructor
Inheritance
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Agenda
 Obligatory Theory
 Simple Sample
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Simple Sample
The Scenario
 Create a solution using Progress OOABL that
will perform the following:
• Feature #1- it will retrieve data from a specific
database table into a temp-table based on
provided WHERE phrase and will provide
access to it
• Feature #2 - it will check access privileges to
the table
• Feature #3 - it will display the data
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Simple Sample
Quiz: The Approach
 Standard Progress ABL
 Sophisticated Progress ABL with includes,
persistent procedures, super procedures
 Progress OOABL
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Simple Sample
Answer: The Approach
 Standard Progress ABL
 Sophisticated Progress ABL with includes,
persistent procedures, super procedures
 Progress OOABL
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Simple Sample
What we will see and will not see
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Encapsulation
Inheritance
Typing
Interfaces
Polymorphism
Delegation
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Simple Sample
The Model
class SimpleSample
«BusinessEntity»
BusinessEntity
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+
h_entity: HANDLE
h_query: HANDLE
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+
+
-
Constructor() : void
Destructor() : void
RetrieveData(CHARACTER) : void
CheckAccess() : LOGICAL
«inherits»
«BusinessEntity»
BECustomer
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+
+
h_custnum: HANDLE
h_name: HANDLE
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+
+
Constructor() : void
Destructor() : void
RetrieveData(CHARACTER) : void
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Simple Sample
Let‘s do it!
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Question?
customer
Tomáš Kučera
[email protected]
Skype: tomas_kucera
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Where to get more
Information resources
 OpenEdge Documentation:
• Getting Started: 10.1B Object-oriented
Programming manual
 PSDN - www.psdn.com
• Library – Products – OpenEdge –
Development Tools & Language – Advanced
Business Language (ABL)
• Library – Product Documentation – OpenEdge
Release 10.1B Product Documentation –
Getting Started
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