ASSOCIATION AND AGGREGATION RELATIONSHIP ASSOCIATION An association represents

ASSOCIATION An association represents a general binary relationship that describes an activity between two

Example of Association Given an association of two classes i. e. student registers up

AGGREGATION Aggregation is a special form of association, which represents an ownership relationship between

Student - firstname: String - lastname: String - home. Address : Address - college.

COMPOSITION Composition represents an exclusively owned relationship by an aggregating object. � It implies

COMPOSITION – cont. In composition, the object is created inside the composed class �

CLASS DIAGRAM Person Name - name: Name - address: Address - firstname: String -

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ASSOCIATION AND AGGREGATION RELATIONSHIP

ASSOCIATION An association represents a general binary relationship that describes an activity between two classes. It allows objects to call methods in other objects through object references � The UML class diagram uses solid line that connects the two classes to represent association relationship between classes as shown below: � Student Register (Course) Course

Example of Association Given an association of two classes i. e. student registers up to 10 courses. 1. . 60 Student register. Course 10 Course Program Student. java, Test. Associate. java and Course. java will illustrate the concept of Association

AGGREGATION Aggregation is a special form of association, which represents an ownership relationship between two classes. � Aggregation models has-a relationship. It is usually represented as a data field in the aggregated class. � In other words, an aggregation object is composed of other objects. � The UML class diagram uses a hollow/empty diamond be attached to the ends of association lines to indicate aggregation. � Student Address

Student - firstname: String - lastname: String - home. Address : Address - college. Address : Address + Student (String, Address, Address) + to. String(): String Address - street: String - city : String - state : String - zip : long + Adress (String, long) + to. String(): String Student. Test CLASS DIAGRAM OF AGGREGATION CONCEPT + main(String[]): void Student. java, Address. java and Student. Test. java Are Java programs that show aggregation concept

COMPOSITION Composition represents an exclusively owned relationship by an aggregating object. � It implies a whole/part relationship. � The UML class diagram uses a solid diamond be attached to the ends of association lines to indicate aggregation � Student Name

COMPOSITION – cont. In composition, the object is created inside the composed class � while in aggregation, the object is created outside the aggregated class. � In composition, when an object is destroyed, other objects belonging to it should be destroyed as well �

CLASS DIAGRAM Person Name - name: Name - address: Address - firstname: String - lastname: String + Person (Name, Address) + get. Name() : Name + to. String(): String + Name (String, String) + get. Full. Name(): String Address Person. Test + main(String[]): void - street: String - city : String - state : String - zip : long + Adress (String, long) + get. Full. Address(): String