#The Adapter Pattern
Intent
Convert the interface of a class into another interface clients expect. Adapter lets classes work together that couldn't otherwise because of incompatible interfaces.
Motivation
- Sometimes a toolkit or class library cannot be used because its interface is incompatible with the interface required by an application
- We cannot change the library interface
- Even if we did have the source code, we should not change the library
Structure
- An adapter relies on object composition
Participants
Target- Defines the domain-specific interface that Client uses.Adaptee- Defines an existing interface that needs adapting.Adapter- Adapts the interface of Adaptee to the Target interface.Client- Collaborates with objects conforming to the Target interface.
Applicability
Use the Adapter pattern when: You want to use an existing class that performs similar functions but with a different interface. For example, a third-party report generator based on xml input.