最全的design pattern 概述.

http://en.wikipedia.org/wiki/Software_design_pattern

Classification and list

Design patterns were originally grouped into the categories: creational patterns, structural patterns, and behavioral patterns, and described using the concepts of delegation, aggregation, and consultation. For further background on object-oriented design, see coupling and cohesion. For further background on object-oriented programming, see inheritance, interface, and polymorphism. Another classification has also introduced the notion of architectural design pattern that may be applied at the architecture level of the software such as the Model-View-Controller pattern.

Name	Description	In Design Patterns	In Code Complete^[12]	In POSA2^[13]	In PoEAA^[14]
Creational patterns
Abstract factory	Provide an interface for creating families of related or dependent objects without specifying their concrete classes.	Yes	Yes	No	No
Builder	Separate the construction of a complex object from its representation so that the same construction process can create different representations.	Yes	No	No	No
Factory method	Define an interface for creating an object, but let subclasses decide which class to instantiate. Factory Method lets a class defer instantiation to subclasses.	Yes	Yes	No	No
Lazy initialization	Tactic of delaying the creation of an object, the calculation of a value, or some other expensive process until the first time it is needed.	No	No	No	Yes
Multiton	Ensure a class has only named instances, and provide global point of access to them.	No	No	No	No
Object pool	Avoid expensive acquisition and release of resources by recycling objects that are no longer in use. Can be considered a generalisation of connection pool and thread pool patterns.	No	No	No	No
Prototype	Specify the kinds of objects to create using a prototypical instance, and create new objects by copying this prototype.	Yes	No	No	No
Resource acquisition is initialization	Ensure that resources are properly released by tying them to the lifespan of suitable objects.	No	No	No	No
Singleton	Ensure a class has only one instance, and provide a global point of access to it.	Yes	Yes	No	No
Structural patterns
Adapter or Wrapper	Convert the interface of a class into another interface clients expect. Adapter lets classes work together that couldn't otherwise because of incompatible interfaces.	Yes	Yes	No	No
Bridge	Decouple an abstraction from its implementation so that the two can vary independently.	Yes	Yes	No	No
Composite	Compose objects into tree structures to represent part-whole hierarchies. Composite lets clients treat individual objects and compositions of objects uniformly.	Yes	Yes	No	No
Decorator	Attach additional responsibilities to an object dynamically keeping the same interface. Decorators provide a flexible alternative to subclassing for extending functionality.	Yes	Yes	No	No
Facade	Provide a unified interface to a set of interfaces in a subsystem. Facade defines a higher-level interface that makes the subsystem easier to use.	Yes	Yes	No	No
Flyweight	Use sharing to support large numbers of fine-grained objects efficiently.	Yes	No	No	No
Proxy	Provide a surrogate or placeholder for another object to control access to it.	Yes	No	No	No
Behavioral patterns
Blackboard	Generalized observer, which allows multiple readers and writers. Communicates information system-wide.	No	No	No	No
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.	Yes	No	No	No
Command	Encapsulate a request as an object, thereby letting you parameterize clients with different requests, queue or log requests, and support undoable operations.	Yes	No	No	No
Interpreter	Given a language, define a representation for its grammar along with an interpreter that uses the representation to interpret sentences in the language.	Yes	No	No	No
Iterator	Provide a way to access the elements of an aggregate object sequentially without exposing its underlying representation.	Yes	Yes	No	No
Mediator	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 it lets you vary their interaction independently.	Yes	No	No	No
Memento	Without violating encapsulation, capture and externalize an object's internal state so that the object can be restored to this state later.	Yes	No	No	No
Null object	Avoid null references by providing a default object.	No	No	No	No
Observer or Publish/subscribe	Define a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically.	Yes	Yes	No	No
Specification	Recombinable business logic in a boolean fashion	No	No	No	No
State	Allow an object to alter its behavior when its internal state changes. The object will appear to change its class.	Yes	No	No	No
Strategy	Define a family of algorithms, encapsulate each one, and make them interchangeable. Strategy lets the algorithm vary independently from clients that use it.	Yes	Yes	No	No
Template method	Define the 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 algorithm's structure.	Yes	Yes	No	No
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.	Yes	No	No	No
Concurrency patterns
Active Object	Decouples method execution from method invocation that reside in their own thread of control. The goal is to introduce concurrency, by using asynchronous method invocation and a scheduler for handling requests.	No	No	Yes	No
Balking	Only execute an action on an object when the object is in a particular state.	No	No	No	No
Binding Properties	Combining multiple observers to force properties in different objects to be synchronized or coordinated in some way.^[15]	No	No	No	No
Messaging pattern	The messaging design pattern (MDP) allows the interchange of information (i.e. messages) between components and applications.	No	No	No	No
Double-checked locking	Reduce the overhead of acquiring a lock by first testing the locking criterion (the 'lock hint') in an unsafe manner; only if that succeeds does the actual lock proceed. Can be unsafe when implemented in some language/hardware combinations. It can therefore sometimes be considered an anti-pattern.	No	No	Yes	No
Event-based asynchronous	Addresses problems with the Asynchronous pattern that occur in multithreaded programs.^[16]	No	No	No	No
Guarded suspension	Manages operations that require both a lock to be acquired and a precondition to be satisfied before the operation can be executed.	No	No	No	No
Lock	One thread puts a "lock" on a resource, preventing other threads from accessing or modifying it.^[17]	No	No	No	Yes
Monitor object	An object whose methods are subject to mutual exclusion, thus preventing multiple objects from erroneously trying to use it at the same time.	No	No	Yes	No
Reactor	A reactor object provides an asynchronous interface to resources that must be handled synchronously.	No	No	Yes	No
Read-write lock	Allows concurrent read access to an object but requires exclusive access for write operations.	No	No	No	No
Scheduler	Explicitly control when threads may execute single-threaded code.	No	No	No	No
Thread pool	A number of threads are created to perform a number of tasks, which are usually organized in a queue. Typically, there are many more tasks than threads. Can be considered a special case of the object pool pattern.	No	No	No	No
Thread-specific storage	Static or "global" memory local to a thread.	No	No	Yes	No

Published on May 21, 2010 in categories