All creational design patterns – library MetaTrader 5
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//+------------------------------------------------------------------+//| PatternOrganizer.mqh |//| 2019-2020, dimitri pecheritsa |//| 792112@gmail.com |//+------------------------------------------------------------------+//| 23 design patterns |//+------------------------------------------------------------------+// design patterns: elements of reusable object-oriented software// gof > erich gamma, richard helm, ralph johnson, john vlissides // published in 1994//+------------------------------------------------------------------+//| classification |//+------------------------------------------------------------------+// purpose > creational > 5// abstract factory, builder, factory method, prototype, singleton// purpose > structural > 7// adapter, bridge, composite, decorator, facade, flyweight, proxy// purpose > behavioral > 11// chain of responsibility, command, interpreter, iterator, mediator// memento, observer, state, strategy, template method, visitor// scope > class > 3 > factory method, interpreter, template method// scope > object > 20 > all other//+------------------------------------------------------------------+//| relationships |//+------------------------------------------------------------------+//// +-------------->|memento| |proxy|// | ^ |adapter|// saving state | |bridge |// of iteration avoiding// | hysteresis// |builder| |iterator|<---+ | | chain of |// ^ ^ | |command| |responsibility|// | | | | |// creating enumerating | composed defining// composites children | using the chain// | | | | |// +---------|composite|<---|---------+---------------+// | | | |// adding | defining------------+ defining// responsibilities | traversals | grammar// to objects | | |// | +--------adding------>|visitor| |// v | operations |// |decorator| sharing | |// ^ composites +--------|interpreter|---+// | | |// | v sharing |// changing skin |flyweight|<-----terminal----+// vs. guts ^ symbols |observer|// | sharing | |// | strategies---+---sharing |// v | states complex// |strategy|------+ | |mediator|<----dependency// ^ |state| management// |// sharing// algorithm's----------|template method|----often uses---+// steps |// |// |prototype|<--+ |// | v// configure factory implement---->|factory method|// dynamically using// | |// |abstract factory|---+---------+// |// single// |singleton|<-----------instance------------|facade|////+------------------------------------------------------------------+//| code refactoring |//+------------------------------------------------------------------+// create objects < explicitly > create indirectly// abstract factory, factory method, prototype// dependence > specific operations > avoid > hard-coded requests// chain of responsibility, command// dependence > hardware and software > limit // abstract factory, bridge// dependence > object representations/implementations// hide from clients > keep changes from cascading// abstract factory, bridge, memento, proxy// algorithmic dependencies > isolate > algorithms that may change// builder, iterator, strategy, template method, visitor// tight coupling > decouple < abstract coupling and layering// abstract factory, bridge, chain of responsibility,// command, facade, mediator, observer// extending functionality < subclassing // composition/delegation > combine behavior// bridge, chain of responsibility, composite, decorator,// observer, strategy// inability to alter classes conveniently > adapter, decorator, visitor//+------------------------------------------------------------------+//| creational > abstract factory |//+------------------------------------------------------------------+// interface > families of related/dependent objects// without specifying concrete classes// variable aspect > families of product objects//// | AbstractFactory|<-----------------------------------------|Client|// |----------------| |// |CreateProductA()| |// |CreateProductA()| |AbstractProductA|<-------+// ^ ^ |// | | |// +-----------+----------+ +-----+-----+ |// | | | | |//|ConcreteFactory1|- + |ConcreteFactory2|- + ->|ProductA2| |ProductA1|<- + |//|----------------| | |----------------| | | |//|CreateProductA()| |CreateProductA()| |//|CreateProductB()| | |CreateProductB()| | | |// |AbstractProductB|<----+--+// | | ^ |// |// | | +-----+-----+ |// | |// | + ->|ProductB2| |ProductB1|<- +// |// + - - - - - - - - - - - - - - - - - - - - - - - - - +////+------------------------------------------------------------------+//| creational > builder |//+------------------------------------------------------------------+// for a complex object > separate construction from representation// same construction process can create different representations// variable aspect > the way a composite object gets created//// builder// | Director |o--------->| Builder |// |-----------------------------| |-----------|// |Construct() | |BuildPart()|// | for all objects in structure| ^// | builder.BuildPart() | |// |ConcreteBuilder|- - ->|Product|// |---------------|// |BuildPart() |// |GetResult() |////+------------------------------------------------------------------+//| creational > factory method |//+------------------------------------------------------------------+// interface for creating an object > defers instantiation to subclasses// subclasses decide which class to instantiate// variable aspect > subclass of object that is instantiated//// | Creator |// |------------------------|// |FactoryMethod() |// |AnOperation() |// | ... |// | product=FactoryMethod()|// |Product| | ... |// ^ ^// | |// |ConcreteProduct|<- - - - -| ConcreteCreator |// |---------------------------|// |FactoryMethod() |// | return new ConcreteProduct|////+------------------------------------------------------------------+//| creational > prototype |//+------------------------------------------------------------------+// create objects > by copying a prototype// variable aspect > class of object that is instantiated//// prototype// | Client |------------>|Prototype|// |--------------------| |---------|// |Operation() | |Clone() |// | p=prototype.Clone()| ^// |// +-----------+------------+// | |// | ConcretePrototype1 | | ConcretePrototype2 |// |--------------------| |--------------------|// |Clone() | |Clone() |// | return copy of self| | return copy of self|////+------------------------------------------------------------------+//| creational > singleton |//+------------------------------------------------------------------+// ensure > one instance of a class with a global point of access// variable aspect > the sole instance of a class//// | Singleton |// |----------------------|// |static Instance() |// | return uniqueInstance|// |SingletonOperation() |// |GetSingletonData() |// |----------------------|// |static uniqueInstance |// |singletonData |////+------------------------------------------------------------------+//| interface for patterns |//+------------------------------------------------------------------+interface ClientExample //pattern client
{
string Output(void); //returns headervoid Run(void); //execute the pattern client
};
//+------------------------------------------------------------------+//| interface for patterns |//+------------------------------------------------------------------+void Run(ClientExample* client) //launches a pattern
{
printf("---n%s",client.Output()); //print pattern header
client.Run(); //execute client collaborationsdelete client; //exit
}
//+------------------------------------------------------------------+//| include > patterns |//+------------------------------------------------------------------+namespace Creational
{
#include "CreationalAbstractFactory.mqh"#include "CreationalBuilder.mqh"#include "CreationalFactoryMethod.mqh"#include "CreationalPrototype.mqh"#include "CreationalSingleton.mqh"
}
//+------------------------------------------------------------------+
//+------------------------------------------------------------------+//| Pattern.mq5 |//| 2019-2020, dimitri pecheritsa |//| 792112@gmail.com |//+------------------------------------------------------------------+#include <SRCPatternsPatternOrganizer.mqh>
//+------------------------------------------------------------------+//| run |//+------------------------------------------------------------------+voidOnStart() //launch pattern clients one by one and check result
{
//---creational
Run(new Creational::AbstractFactory::Client);
Run(new Creational::Builder::Client);
Run(new Creational::FactoryMethod::Client);
Run(new Creational::Prototype::Client);
Run(new Creational::Singleton::Client);
}
//+------------------------------------------------------------------+//| output > abstract factory |//+------------------------------------------------------------------+// Creational::AbstractFactory::Client::Output// client is requesting to create factory 1// client is requesting to create the factory client// client is requesting the factory client to manage factory 1// factory 1: 3145728 constructed// factory client created and received abstract factory 3145728// factory client is requesting to accept/switch the factories// factory client is accepting new factory 3145728// factory client saved the new factory// factory client is requesting its new factory to create product a// factory 1 is creating and returning product a1// product a1 constructed// factory client is requesting its new factory to create product b// factory 1 is creating and returning product b1// product b1 constructed// client is requesting the factory client to operate// factory client is running abstract product b// product b1: 5242880 is interacting with product a: 4194304// client is requesting to create new factory 2 and asking factory client to switch factories// factory 2: 6291456 constructed// factory client is switching old factory 3145728 to new factory 6291456// factory client saved the new factory// factory client is requesting its new factory to create product a// factory 2 is creating and returning product a2// product a2 constructed// factory client is requesting its new factory to create product b// factory 2 is creating and returning product b2// product b2 constructed// client is requesting the factory client to run again// factory client is running abstract product b// product b2: 8388608 is interacting with product a: 7340032//+------------------------------------------------------------------+//| output > builder |//+------------------------------------------------------------------+// Creational::Builder::Client::Output// client is requesting to create a new concrete builder// client is requesting to create a director and give him the builder// director created and received builder 10485760// client is requesting the director to perform the construction// director has started the construction// director is requesting its builder to build the product parts// builder is requesting the product to add part a to itself// product added part a to itself// builder has made part a and added it to the product// builder is requesting the product to add part b to itself// product added part b to itself// builder has made part b and added it to the product// builder is requesting the product to add part c to itself// product added part c to itself// builder has made part c and added it to the product// director's builder constructed the product from parts// client is requesting the builder to return the result product// builder is returning the product// client is requesting the product the describe itself// product is showing all parts that it is made of// part a// part b// part c//+------------------------------------------------------------------+//| output > factory method |//+------------------------------------------------------------------+// Creational::FactoryMethod::Client::Output// requesting to make a creator// requesting creator to run its factory method to return the product// creator is running a factory method// concrete creator is creating and returning new concrete product// concrete product: 15728640 created// requesting creator to run its operation// creator is running its operation// creator is running a factory method// concrete creator is creating and returning new concrete product// concrete product: 16777216 created// creator has saved the product received from a virtual factory method//+------------------------------------------------------------------+//| output > prototype |//+------------------------------------------------------------------+// Creational::Prototype::Client::Output// requesting to create a concrete prototype 1 with id 1// prototype 18874368, id: 1 created// concrete prototype 1: 18874368, id: 1 created// requesting prototype 18874368 to create its clone// cloning concrete prototype 1: 18874368, id: 1// prototype 19922944, id: 1 created// concrete prototype 1: 19922944, id: 1 created// requesting to create a concrete prototype 2 with id 2// prototype 20971520, id: 2 created// concrete prototype 2: 20971520, id: 2 created// requesting prototype 20971520 to create its clone// cloning concrete prototype 2: 20971520, id: 2// prototype 22020096, id: 2 created// concrete prototype 2: 22020096, id: 2 created//+------------------------------------------------------------------+//| output > singleton |//+------------------------------------------------------------------+// Creational::Singleton::Client::Output// requesting singleton instance 1// singleton instance method is running// unique instance of the singleton is empty// singleton 24117248 created// singleton assigned to unique instance// unique instance contains singleton: 24117248// returning the unique instance 24117248 of the singleton// requesting singleton instance 2// singleton instance method is running// unique instance contains singleton: 24117248// returning the unique instance 24117248 of the singleton// instances 1 and instance 2 are same objects// requesting singleton operation on instance 1// running singleton operation > setting singleton data// requesting singleton data via singleton instance 2// reading and returning singleton data// singleton data//+------------------------------------------------------------------+
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