GeneralTradingSarl
187 lines
16 KiB
Plaintext
187 lines
16 KiB
Plaintext
//+------------------------------------------------------------------+
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//| PROGRAMMING PATTERNS - STRATEGY |
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//| Incapsulate a family of interchangeable algorythms which can be |
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//| modified independently from the client. |
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//| |
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//| OOP CONCEPTS: Abstraction, Encapsulation, Polymorphism, |
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//| Inheritance |
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//| |
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//| RULES: |
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//| Encapsulate changes |
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//| Composition is better than inheritance. |
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//| Engineer with interfaces, not real classes. |
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//| |
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//| A good architecture is extendable, supportable, and reusable. |
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//| Patterns help build hq systems. |
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//| Patterns are proven to be good by experience. |
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//| Patterns are generic solitions for software engineering |
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//| challenges. |
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//| Choose your pattern, don't invent it. |
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//| Most patterns are designed to manage changes of the architecture.|
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//| Most patterns incapsulate variable aspects of the systems. |
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//| Developers know patterns and effectively communicate with each |
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//| other. |
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//+------------------------------------------------------------------+
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//+------------------------------------------------------------------+
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//| BEHAVIOR A INTERFACE |
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//+------------------------------------------------------------------+
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interface I_BehaviorA
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{
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void Act();
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};
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//+------------------------------------------------------------------+
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//| BEHAVIOR B INTERFACE |
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//+------------------------------------------------------------------+
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interface I_BehaviorB
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{
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void Act();
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};
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//+------------------------------------------------------------------+
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//| REAL BEHAVIOR A - OPTION A |
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//+------------------------------------------------------------------+
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class C_BehaviorAA : public I_BehaviorA
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{
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public:
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void Act() { Print(" • Doing A the a way"); }
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};
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//+------------------------------------------------------------------+
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//| REAL BEHAVIOR A - OPTION B |
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//+------------------------------------------------------------------+
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class C_BehaviorAB : public I_BehaviorA
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{
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public:
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void Act() { Print(" • Doing A the b way"); }
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};
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//+------------------------------------------------------------------+
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//| REAL BEHAVIOR A - OPTION C |
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//+------------------------------------------------------------------+
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class C_BehaviorAC : public I_BehaviorA
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{
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public:
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//--- empty implementation
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void Act() { Print(" • Doing A is impossible"); }
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};
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//+------------------------------------------------------------------+
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//| REAL BEHAVIOR B - OPTION A |
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//+------------------------------------------------------------------+
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class C_BehaviorBA : public I_BehaviorB
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{
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public:
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void Act() { Print(" • Doing B the a way"); }
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};
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//+------------------------------------------------------------------+
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//| REAL BEHAVIOR B - OPTION B |
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//+------------------------------------------------------------------+
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class C_BehaviorBB : public I_BehaviorB
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{
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public:
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void Act() { Print(" • Doing B the b way"); }
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};
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//+------------------------------------------------------------------+
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//| REAL BEHAVIOR C - OPTION C |
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//+------------------------------------------------------------------+
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class C_BehaviorBC : public I_BehaviorB
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{
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public:
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//--- empty implementation
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void Act() { Print(" • Doing B is impossible"); }
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};
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//+------------------------------------------------------------------+
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//| ABSTRACT OBJECT |
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//+------------------------------------------------------------------+
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class A_Object
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{
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public:
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~A_Object()
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{
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if(CheckPointer(behavior_a)==POINTER_DYNAMIC) delete behavior_a;
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if(CheckPointer(behavior_b)==POINTER_DYNAMIC) delete behavior_b;
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}
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virtual void Name()=0;
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void ActA() { behavior_a.Act(); }
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void ActB() { behavior_b.Act(); }
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void ActC() { Print(" • Doing C the common way"); }
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void SetBehaviorA(I_BehaviorA *b)
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{
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if(CheckPointer(behavior_a)==POINTER_DYNAMIC) delete behavior_a;
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behavior_a=b;
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}
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void SetBehaviorB(I_BehaviorB *b)
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{
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if(CheckPointer(behavior_b)==POINTER_DYNAMIC) delete behavior_b;
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behavior_b=b;
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}
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protected:
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I_BehaviorA *behavior_a;
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I_BehaviorB *behavior_b;
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};
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//+------------------------------------------------------------------+
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//| REAL OBJECT A |
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//+------------------------------------------------------------------+
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class C_ObjectA : public A_Object
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{
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public:
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//--- default behavior
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C_ObjectA()
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{
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behavior_a=new C_BehaviorAA();
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behavior_b=new C_BehaviorBA();
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}
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void Name() { Print("Object A"); }
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};
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//+------------------------------------------------------------------+
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//| REAL OBJECT B |
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//+------------------------------------------------------------------+
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class C_ObjectB : public A_Object
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{
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public:
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//--- default behavior
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C_ObjectB()
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{
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behavior_a=new C_BehaviorAB();
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behavior_b=new C_BehaviorBA();
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}
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void Name() { Print("Object B"); }
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};
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//+------------------------------------------------------------------+
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//| CLIENT |
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//+------------------------------------------------------------------+
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void OnStart()
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{
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//--- default real object behavior
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A_Object *object_a=new C_ObjectA;
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object_a.Name();
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object_a.ActA();
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object_a.ActB();
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object_a.ActC();
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//--- dynamically change behavior
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A_Object *object_b=new C_ObjectB;
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object_b.Name();
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object_b.ActA();
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object_b.ActB();
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object_b.ActC();
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object_b.SetBehaviorA(new C_BehaviorAA);
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object_b.ActA();
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object_b.SetBehaviorA(new C_BehaviorAC);
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object_b.ActA();
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//---
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delete object_a;
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delete object_b;
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}
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//+------------------------------------------------------------------+
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//| OUTPUT |
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//| |
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//| Object A |
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//| • Doing A the a way |
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//| • Doing B the a way |
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//| • Doing C the common way |
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//| Object B |
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//| • Doing A the b way |
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//| • Doing B the a way |
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//| • Doing C the common way |
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//| • Doing A the a way |
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//| • Doing A is impossible |
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//+------------------------------------------------------------------+
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