Static Class Structure

• Client
  • Refers to the Component interface.
• Component
  • Defines a common interface for Leaf and Composite objects.
• Leaf
  • Defines individual objects that get composed.
• Composite
  • Maintains a container of child Component objects (children).
  • Forwards requests to these children (for each child in children: child.operation()).

Dynamic Object Collaboration

• In this sample scenario, a Client object sends a request to the top-level Composite object in the hierarchy.
• The request is forwarded to the child Component objects (lower-level Leaf and Composite objects) recursively, that is, the request is performed on all objects downwards the hierarchy.
• A Composite object may do work of its own before and/or after forwarding a request, for example, to compute total prices (see Sample Code / Example 2).
• See also Sample Code / Example 1.