What is Abstract Factory?
- Provide an interface for creating families of related or dependent objects without specifying their concrete classes.
What is an Adapter?
- Convert the interface of a class into another interface clients expect. Adapter lets classes work together that couldn’t otherwise because of incompatibility interfaces.
What is a Bridge?
- Decouple an abstraction from its implementation so that the two can very independetly.
What is a builder?
- Separate the construction of a complex object from its representation so that the same construction processes can create different representations.
What is the Chain of Responsibility?
- Avoid coupling the sender of a request to its receiver by giving more than one object a chance to handle the request. Chain the receiving objects and pass the request along the chain until an object handles it.
What is a command?
- Encapsulate a request as an onject, thereby letting you parameterize clients with different requests, queue or log requests, and support undoable operations.
What is Composite?
- Compose objects into tree structures to represent part-whole hierarchies. Composite lets clients treat individual objects and compositions of objects uniformly.
What is a Decorator?
- Attach additional responsibilities to an object dynamically. Provide a flexible alternative to subclassing for extending functionality.
What is a Facade?
- Provide a unified interface to a set of interfaces in a system. Facade defines a higher-level interface that makes the subsystem easier to use.
What is Factory Method?
- Define an interface for creating an object, but let the subclasses decide which class to instantiate. Factory Method lets a class defer instantiation to subclasses.
What is Flyweight?
- use sharing to support large numbers of fine-grained objects efficiently. A flyweight is a shared object that can be used to multiple contexts simultaneously. The flyweight acts as an independent object in each context; it’s indistinguishable from an instance of an object that’s not shared.
What is an Interpreter?
- Given a language, define a representation for its grammar along with an interpreter that uses the representation to interpret sentences in a language.
What is an Iterator?
- Provides a way to access the elements of an aggregate object sequentially without exposing its underlying representation.
- Define an object that encapsulates how a set of objects interact. Mediator promotes loose coupling by keeping objects from referring to each other explicitly, and lets you vary their interaction independently.
What is Memento?
- Without violating encapsulation, capture and externalize an object’s internal state so that the object can be restored to this state later.
What is an Observer?
- Define a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically.
What is a Prototype?
- Specify the kinds of objects to create using a prototypical instance, and create new objects by copying this prototype.
What is a Proxy?
- Provide a surrogate or placeholder for another object to control access to it.
What is a Singleton?
- Ensure a class only has one instance, and provide a global point of access to it.
What is a State?
- Allow an object to alter its behavior when its internal state changes. The object will appear to change its class.
What is Strategy?
- Defines a family of algorithms, encapsulates each one, and make them interchangeable. Strategy lets the algorithm vary independently from clients who use it.
What is a Template?
- Define a skeleton of an algorithm in an operation, deferring some steps to subclasses. Template Method lets subclasses redefine certain steps of an algorithm without changing the algorithms structure.
What is a Visitor?
- Represent an operation to be performed on the elements of an object structure. Visitor lets you define a new operation without changing the classes of the elements on which it operates.