UML structure of the Composite design pattern

Composite design pattern is based on the composition of similar types of objects into the tree structure, as you know that each tree has three main parts branch, node, and leaf. So let's have a look at the following terms used in this design pattern.

Component: It is basically a branch of the tree and the branch has other branches, nodes, and leaves. Component provides the abstraction for all components, including composite objects. In the composition pattern, component is basically declared as an interface for objects.

Leaf: It is an object that implements all component methods.

Composite: It is represented as a node in the tree structure, it has other nodes and leaves, and it represents a composite component. It has methods to add the children, that is, it represents a collection of the same type of objects. It has other component methods for its children.

Let's look at the following UML diagram for this design pattern:

Benefits of the Composite design pattern

• This pattern provides the flexibility to add new component to process dynamically, with change in the existing components
• This pattern allows you to create a class hierarchy that contains individual and composite objects