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Difference in Aggregation and Composition

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#1

How is Object Association’s Composition different from Aggregation? And what makes Composition stronger than Aggregation?

#2

Hi @Shantanu_Das !!
Object association, composition, and aggregation describe relationships between objects.

  1. Object Association:

    • Object association is a generic term for a relationship between two or more objects in a system.
    • It can be a one-to-one, one-to-many, or many-to-many relationship.
    • The association doesn’t specify the strength or lifetime of the relationship.

  2. Aggregation:

    • Aggregation is a specific type of association where one object is composed of or owns another object.
    • It represents a whole-part relationship where the child object can exist independently of the parent.
    • Aggregation is generally considered to be a weaker relationship, and the child objects can be shared among multiple parent objects.

  3. Composition:

    • Composition is a stronger form of aggregation where the child objects are considered integral parts of the parent object.
    • The child objects have a strong lifecycle dependency on the parent, meaning they are created and destroyed along with the parent.
    • If the parent is destroyed, the child objects are usually destroyed as well.

Strengths of Composition over Aggregation:

  • Stronger Relationship: In composition, the objects are more tightly bound, and the relationship is stronger compared to the relatively loose relationship in aggregation.
  • Better Encapsulation: Composition often results in better encapsulation as the internal details of the composed object are hidden within the parent.
  • Simplifies Interfaces: Since the child objects are part of the parent, their interfaces can be simplified, and the overall design becomes more intuitive.

In summary, composition is considered stronger than aggregation because it implies a more significant level of dependency and ownership between the objects involved. The choice between composition and aggregation depends on the specific requirements and the nature of the relationship between the objects in a given system.
I hope it helps. Happy Learning :blush: