Objects and Components. The adaptive organization. The competitive environment of businesses continuously changing , and the pace of that change is increasing at an accelerating rate.
simply because there appears to be no other way to economically produce an enduring and resilient programming system.
objects are the enabling technology for adaptive business systems
Project proposal report
tests of system performance
audit , feed-back
- intermediate reports
- go/nogo intervals
With the increasing complexity of the systems,
the traditional techniques suffer from two illusions:
develop a series of solutions to a problem ,
each of them closer to satisfying the requirements
( also called : evolutionary development )
Builds system functionality a little at a time.
The results are not entire solutions.
Matthew Pittman proposes iterative analysis and design combined with incremental development
coordination and reuse
OO - system
whereby operations are encapsulated together with the data structures on which they are defined
1 y comp
From: Grady Booch
Abstraction focuses upon the essential characteristics of some object,
relative to the perspective of the user
From: Grady Booch
Encapsulation hides the details of the
implementation of an object
classes are set up at design time
The task of software development is to engineer the illusion of simplicity.
The set of messages an object commits to respond to.
1. A receiver object
2. A method the receiver knows how to execute
3. An ordered set of parameters that this method requires to carry out this function (optional)
Vehicle Turn : 90
receiver method parameter
Messages conform to signatures
students and staff members are sub-classes of person
it is possible to
This is not inheritance (but Aggregation)
The IDL specification allows objects from different vendors, written in different languages to interact without any knowledge of one another's classes.
The use of interfaces can eliminate most class dependencies.
Exception made for inheritance where class references remain unavoidable.
Microsoft COM technology for ActiveX objects does not includes inheritance.
Object Request Broker
1. Condition: variable or method that evaluates to true or false
2. Action: method defined within the class that contains the rule