- Deal with assigning responsibilities between different objects. Describe the communication mechanism between objects, define a mechanism for choosing different algorithms by different objects at runtime..
- Allow a request to be encapsulated into a object, thereby letting you parametrize clients with different request.
- Helps to interpret operations using its grammar.
- Given a language, define a representation for its grammar along with an interpreter that uses the representation to interpret sentences in the language.
- Encapsulates the direct object communication details among a set of objects in a separate (mediator).
- Define an object that encapsulates how a set of objects interact.
- Allows the state of an object to be captured and stored.
- Promotes a publisher-subscriber communication model when there is a one-to-many dependency between objects so that when one object change of state, all of its dependents are notified so they can update their state.
- Define a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically.
- Allow to encapsulate the different states of an object as an object, which specific state mapped onto an object.
- Allow an object to alter its behavior when its internal state changes. The object will appear to change its class.
- Allows each of a family of related algorithms to be encapsulated into a set of different subclasses (strategy objects) of a common superclass.
- Define a family of algorithms, encapsulated each one and make them interchangeable.
- Define the skeleton of an algorithm in an operation.
