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 |