• A new way of thinking about software based on abstractions that exist in the real world
• The essence of object-oriented development is the identification and organization of application demain concepts, rather than their final representation in a programming language.

• Coad/Yourdon
• Rumbough-Object modeling techniques (OMT)
• Objectory and Object-oriented sofware Engineering
• Object-oriented system analysis (OSA)
• .......

Object Modeling Techniques (OMT)

• An object-oriented development methodology that uses object, dynamic and functional medels throughout the development life cycle.
• Software stage
 
• Analysis
• A stage in the development cycle in which real world problem is examined to understand its requirement wihout planning the implementation.
• System design
• The first stage of design, during which high-level decisions are made about the overall structure of the system, its architecture, and the stratergies used to implement the system.
• Object Design
• A stage of the development cycle during which the implementation of each class, association, attribute, and operation is determined.
• Implementation
• A stage in the development life cycle in which a design is realized in an executable form, such as a programming language or hardware.

• The OMT uses three models to describe a system
• Object Models, Dynamic Models & Functional Medels
• Object Model (WHAT)
• The static structure of the object in a system that includes the identity, relationships to other objects, attributes and operation.
• Dynamic Model (WHEN)
• The aspect of a system that change overtime - concerned control, including time, sequencing operation and interaction of objects.
• Functional Model (HOW)
• The aspect of a system that tranform values using functions, mapping, constraint and functional dependencies.

Capture the static structure of a system

1. relationship between objects
2. the attributes and operations that characterize each class of objects

• Important concepts
• object and class
• link and association
• aggregation
• generalization and inheritance
 

• Object - refer to exactly one thing and can be distinguished
• Example:
 

• refer to a group of similar thing
• a group of similar object with similar properties (operation), common relationships to other objects and common semantics.
• Example :

A formal graphic notation for modeling objects, classes and their relationship to one another.

• Class diagram
• schema, pattern or template for describing many possible instances.
• Instance diagram
• how a particular set of objects relate to each other.
• example :
 

• A named property of a class describing a data value held by each object of the class.
• Example :
 

• Operations
• is a function or tranformation that may be applied to object in a class
• Method
• is the implementation of an operation for a specific class
• Example:
 

• A link
• is a physical or conceptual connection between object instances
• An association
• describes a groups a group of links with common structure and common semantics.
 
 
                             One-to-one association and link
 
 
 
 
 
                      Many-to-many association and links
 
 
                        Ternary association and links
 

• specify how many instances of one class may relate to a single instance of an associated class.
• specify with a number or set of intervals:
• "1"            exactly one
• "1+"          one or more
• "3-5"         three to five, inclusive
• "2,4,18"    two, four, or eighteen
• example :
 

• Aspecial form of association between a whole and its part, in which the whoke is composed of the parts.
• Example:
 

• Powerful abstraction for sharing similarities among classses while preserving the differences.
• Generalization
• is the relationship between a class and one or more refined version of it.
• subclass
• superclass
• Inheritance
• is an object-orientaed mechanism that permits classes to share attributes and operations based on a relationship, usually generalization.
 
 

Latihan

Latihan 1

1. List the object classes that is needed to make up this course. Prepare an object diagram that shows the relationship among the object classes. Include association, aggregations and generalizations.
2. Prepare an instance disgram for the class diagram below for the expression (X+Y/2)/(X/3+Y)

Kuiz 1

Preapare an object diagram for a graphical document editor that supports gouping, which is a concept used in a variety of graohical editors, including text, geometrical objects and groups. A group is simply a set of drawing object, possibly including other groups. A group must contain at least two drawing objects. A drawing object can be a direct member of at most one group. Geometrical objects include circles, ellipses, rectangle, line and squares.
 
 

Assignment

Sediakan object diagram untuk menunjukkan sekurang-kurangnya 10 hubungan di antara object classes berikut. Termasuk association, aggregation dan generalization. Gunakan qualified association dan tunjukkan multipicity dalam rajah anda. Anda tida perlu menunjukkan atrribut dan operasi. Gunakan nama association jika diperlukan.Dalam menyediakan rajah, kemungkinan ada penambahan object classes baru.
 

1. school, playground, principal, school board, classroom, book, student, teacher, cafeteria, rest room, computer, desk, chair, ruler, door, swing.
2. castle, moat, drawbridge, tower, ghost, stairs, dungeon, floor, corridor, room, window, stone,lord, lady, cook.
3. expression, constant, variable, function, argument list, relational operator, term,factor, arithmetic operator, statement, program.
4. file system, file, directory, file name, ASCII file, executable file, directory file, disk, drive, track, sector.
5. automobile,engine, wheel, brake, brake light, door, battery, muffler, tail pipe.
6. gas furnace blower, blower motor, room thermostat, furnace thermostat, humidifier, humidity sensor, gas control, blower control, hot air vents.
7. chess piece, rank, file, square, board, move, position, sequence of moves
8. sink, freezer, refrigerator, table, light, switch, window, smoke alarm, burglar alarm, cabinet, bread, cheese, ice, door, kitchen.