Ray's playground

摘要： When Would You Use the Composite Pattern? You would naturally think about using the pattern whenYou want to have abstract tree representation of objects (part-wholehierarchies). You want clients to treat all objects in the composite structure andindividual objects uniformly. 阅读全文

摘要： Defines a one-to-many dependency between objects so that whenone object changes state, all its dependents are notified and updated automatically. 阅读全文

摘要： The Mediator pattern is used to define a centralized place where interactions amongobjects can be handled in one mediator object. Other objects don’t need to interact witheach other directly, so it reduces dependency among them. 阅读全文

摘要： There are three common situations in which you would consider using this pattern: Your subsystem is getting complex. A lot of classes are evolved fromapplying patterns. You can use a façade to provide a simpler interfacefor the subsystem classes. You can use façades to layer your subsystem 阅读全文

摘要： Abstraction is the parent interface that defines the high-level abstraction interface usedby clients. It has a reference to an instance of Implementor, which defines the interfacefor implementation classes. This interface doesn’t need to correspond to Abstraction’sinterface; in fact, they can be qu. 阅读全文

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摘要： #import"Singleton.h"@implementationSingletonstaticSingleton*sharedSingleton=nil;+(Singleton*)sharedInstance{if(sharedSingleton_==nil){sharedSingleton_=[[superallocWithZone:NULL]init];}returnsharedSingleton_;}+(id)allocWithZone:(NSZone*)zone{return[[selfsharedInstance]retain];}-(id)copyWith 阅读全文

摘要： We discussed Abstract Factory in the last chapter. You might have realized that both the Abstract Factoryand Builder patterns are similar in many ways in terms of being used for abstract object creation. However,they are very different. Builder focuses on constructing a complex object step-by-step,. 阅读全文

摘要： The Abstract Factory and Factory Method patterns are very similar in many ways. It’s very confusing tomany people when to use which one of them. Both of them can be used for the same purposes of creatingobjects without letting clients know what exact concrete objects are being returned. The followi. 阅读全文

摘要： The abstract Product defines the interface of objects the factory method creates. TheConcreteProduct implements the Product interface. The Creator defines the factorymethod that returns an object of Product. It may also define a default implementation ofthe factory method that returns a default Con. 阅读全文