Visitor patterns for Behavioral design patterns

structure
intent
applicability	An object structure contains many classes of objects that have different interfaces, and you want to implement some operations that depend on their specific classes for those objects. You need to do a lot of different and unrelated operations on objects in an object structure, and you want to avoid classes that let these actions "pollute" those objects. Vi s i t o r allows you to centralize related operations into one class. When the object structure is shared by many applications, the vi s i t o r mode allows each app to contain only the actions that need to be used.

1  usingSystem;2 3     Abstract classVisitor4     {5         Abstract  Public voidVisitelementa (Concreteelementa a);6         Abstract  Public voidVISITELEMENTB (Concreteelementb b);7     }8 9     classConcretevisitor1:visitorTen     { One         Override  Public voidVisitelementa (Concreteelementa a) A         { -              -         } the  -         Override  Public voidVISITELEMENTB (CONCRETEELEMENTB b) -         { -              +         } -     } +  A     Abstract classElement at     { -         Abstract  Public voidAccept (Visitor v); -     } -  -     classconcreteelementa:element -     { in          PublicVisitor Myvisitor; -         Override  Public voidAccept (Visitor v) to         { +Myvisitor =v;  -         } the  *          Public voidOperationa () $         {Panax Notoginseng              -         } the  +          Public voiddosomework () A         { the             //Do some +             // . . . -  $             //Get visitor to visit $Myvisitor.visitelementa ( This);  -  -             //Do some the             // . . . -         }Wuyi     } the  -     classconcreteelementb:element Wu     { -         Override  Public voidAccept (Visitor v) About         { $              -         } -  -          Public voidoperationb () A         { +              the         } -     } $  the     /// <summary> the     ///Summary description for Client. the     /// </summary> the      Public classClient -     { in          Public Static intMain (string[] args) the         {             theConcreteelementa EA =NewConcreteelementa (); AboutCONCRETEELEMENTB EB =Newconcreteelementb (); theConcreteVisitor1 V1 =NewConcreteVisitor1 (); the  the ea.accept (v1); + ea.dosomework (); -  the             return 0;Bayi         } the}

Visitor Mode

Visitor patterns for Behavioral design patterns