www.cs.vu.nl/~eliens/online/courses/cmg/oo

Topics:

• OO technology
• The OO life cycle
• Project Management
• Application Frameworks
• Current developments and trends

Keywords and phrases

• the OO lifecycle -- modeling
• encapsulation, inheritance, delegation, polymorphism
• specification and implementation inheritance
• design by contract
• interfaces, components and frameworks
• idioms, patterns, software architecture

Characterizations

• OO = encapsulation + inheritance
• OO = data abstraction + polymorphism
• OO = interfaces + components
• OO = types + implementations
• OO = CORBA + Application Frameworks
• OO = Java + nothing else
• OO = a metaphor + hype
• OO = everything I can sell ...

Let's have a look at the Introduction from Principles of Object-Oriented Software Development

   Did
      YOU
         ever
  	    manage
  		    a 
  		       project?
  

Critical Success Factors

• use incremental scheduling and staging
• find and fix failing ideas
• develop a habit of delivering
• Get: sponsor, project manager, technical leader

Key Failure Indicators

• absence of incremental development
• use of C++ in commercial IS

see Surviving Object-Oriented Projects: A managers Guide

OO - Success and Failure

• OO = technology + mind-set
• it might be new technology to your organisation
• developers love it!
• requires and enables communication between groups
• adopting OO may succeed or fail!

Possible benefits - responsiveness

• responsiveness - variations on a theme
• responsiveness to change!
• time-to-market
• communication - developers, users, executives
• maintenance, reuse, productivity
• GUI development
• morale -- cutting-edge technology

Drawbacks

• Are YOU underestimating?
• productivity takes time
• hazards of C++ (and Java, ...)
• reuse is difficult
• establishing a software process
• business-modeling or software design?
• CASE helps?
• You will pay for: training, experience, tools, consultants, ...

The hazards of C++?

• C++ won the language war over Eiffel, Objective-C, SOM, C@+, and Java?
• Java -- relative simplicity and portability

Managing (the complexity of) C++

• misconception: C++ is like C
• consider using another language
• Why does C++ exist? - engineering and systems programming
• create a subset of the language
• design and coding standards
• use people with knowledge!

Risk-reduction Strategies

• look carefully all around the project
• detect the risks!
• list the risks in order
• work on the risks in order of danger

see Risk Avoidance Patterns

Applications Frameworks

• The hush Framework

Design by Contract

• formal basis -- pre and post conditions
• refinement -- by inheritance or polymorphism
• runtime checks -- division of responsibility

see Ch. 3, Contracts

Frameworks = Components + Patterns

Ralph Johnson, CACM Nov. 1997

Self-documentation Principle

Bertrand Meyer, OO Software Construction 2nd ed.

the designer of a module should strive to make all information about the module part of the module itself ...

A Framework defines an Architecture?

see patterns

A Catalogue of Design patterns

• a common design vocabulary
• documentation and learning aid
• an adjunct to existing methods
• a target for redesign

see the GOF Design Patterns and the Patterns Homepage

CORBA

• the issue is standardization
• by means of interfaces
• looking for consensus
• this differs from a de-facto standard
• imposed by market share ...

See Ch 6: Component Technology

Dimensions of Risks

• Knowledge
• Teaming
• Productivity
• Ownership
• Distractions

Don't discuss risks, unless you know how to do Project Management

knowledge

• clear the fog -- get to the real issues
• early and regular delivery -- discover what you don't know
• prototype! -- discover how it really works
• create microcosm -- do something real, but with care

teaming

• holistic diversity -- coordinate specialists!

productivity

• gold rush -- start immediatly, adjust slowly

ownership

• function / component owners -- create responsibility

distraction

• someone always makes progress -- no total interruption
• team per task -- a subteam deals with diversions
• sacrifice one person -- and preserve the team

training

• day care -- hire an expert to take care of novices

OO offers

• a valid metaphor for SE
• powerful technology
• maturing design methods and notations
• a rich set of patterns

Yet beware of

• the learning curve
• simplified hype
• cutting edge technology
• (over) ambitious projects