Object-oriented Software in Ada 95

Preface
xix
Instance
attribute
A data component contained in an object. In Ada the data components are
contained in a record structure in the private part of the package.
type Account is record
Balance_Of : Money := 0.00; --Instance attribute
end record;
Instance method
A procedure of function in a class that accesses the instance attributes (data
items) contained in an object. For example, the method Balance accesses
the instance attribute Balance_Of.
function Balance( The:in Account ) return Money is
begin
return The.Balance_Of;
end Balance;
Instantiation
The act of creating a specific instance of a generic unit. For example, the
generic package Integer_Io in the package Ada.Text_Io can be
instantiated to deliver the package Pack_Mark_Io which performs I/O on
the integer type Exam_Mark as follows:
type Exam_Mark is range 0 .. 100;
package Pack_Mark_Io is new
Ada.Text_Io.Integer_Io(Exam_Mark);
Then a programmer can write
Miranda : Exam_Mark;
Pack_Mark_Io.Put( Miranda );
to write the contents of the Integer object Miranda.
Message
The sending of data values to a method that operates on an object. For
example, the message 'deposit £30 in account Mike' is written in Ada as:
Deposit( Mike, 30 );
Note: The object to which the message is sent is the first parameter.
Meta-class
Method
Multiple
inheritance
An instance of a meta-class is a class. Meta-classes are not supported in Ada.
Implements behaviour in an object. A method is implemented as a procedure
or function in a class. A method may be either a class method or an instance
method.
A class derived from more than one base class. Multiple inheritance is not
directly supported in Ada.
© M A Smith - May not be reproduced without permission