Advantages (+)

• Simplifies clients.
  • Clients can treat all objects in the hierarchy uniformly, which greatly simplifies client code.
• Makes adding new components easy.
  • Clients refer to the common Component interface and are independent of its implementation.
  • That means, clients do not have to be changed when new Composite or Leaf classes are added or existing ones are extended.
• Allows building and changing complex hierarchies dynamically at run-time.
  • The pattern shows how to apply recursive composition to build complex hierarchical object structures dynamically at run-time.

Disadvantages (–)

• Uniformity versus type safety.
  • There are two main design variants to implement child-related operations: design for uniformity and design for type safety (see Implementation).
  • The Composite pattern emphasizes uniformity over type safety.