http://www.icst.pku.edu.cn/CompCourse

1
????????

• ???
• http//www.icst.pku.edu.cn/CompCourse

2
??

• ??
• Generic Programming
• ????patterns
• ????(framework)???
• ??????????

3
??creational patters

• Factory Method
• ?????virtual method??????
• Abstract Factory
• ??product??factory method?????factory??
• Prototype
• ??product?????product,Cloneprototype manager
• Builder
• ?????????builder?????????????
• Singleton
• ?????,????????????????????
• Finder
• ??????????????

4
??Structural patterns

• Adapter ?bridge?facade
• adapter??????????????
• bridge???????????????????
• facade??????????????????????
• composite?decorator?proxy
• composite??????????
• decorator???????????
• proxy????????????
• flyweight
• ????????????????

5
??Behavioral Patterns

• Command
• ???????,????????????????
• Iterator
• ??????????????
• Observer
• ???????????,??????????????
• Strategy
• ?????????????????????????
• Visitor
• ????????????????????

6
??Behavioral Patterns(??)

• Chain of Responsibility
• ???????,?????,decouple???????
• Interpreter
• ???????,??????interpret??
• Mediator
• ???mediator?decouple?????
• Memento
• ??????????????
• State
• ????????????,????????????
• Template Method
• ???????????,???????????

7
??Behavioral Patterns(??)

• Strategy?Iterator?Mediator?State?command
• ????????????,????????????????
• Mediator?Observer
• Observer???subject?observer????????
• mediator????????? -gt????
• command?Chain of Responsibility?interpreter
• command????????????
• Chain of Responsibility??????????
• interpreter??????????????

8
Generic programming

• ??
• ??????????????(reuse through parameterization),?
  ??????????????????,?????????? Generic
  Programming????????????????????
• STL????generic programming??
• generic programming????????????????????,?????????
  ???????????,???????????

9
???programming

• Aspect-Oriented Programming (AOP)
• An aspect is a modular unit that cross-cuts the
  structure of other modular units
• Aspects exist in both design and implementation.
  A design aspect is a modular unit of the design
  that cross-cuts the structure of other parts of
  the design. A program or code aspect is a
  modular unit of the program that cross-cuts other
  modular units of the program.
• ??????????(??)?aspect
• ?AOP???,???aspects(??)????????????????????????comp
  ile-time,????runtime
• AOSD, ??http//aosd.net/

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generative programming

• Generative Programming
• ????????????,???????,??????????????,????,?????????
  ?????????????????
• ????
• ?????????????
• ???????????????
• ??????(compile-time)????????,??????????????
• ????????????,?????????????
• Separation of concerns borrowed from AOP
• ??
• Generative Programming??????????????
• ?Domain Engineering??
• A Model-Based Approachhttp//www.sei.cmu.edu/doma
  in-engineering/domain_engineering.html
• Active Libraries

11
C Generic Programming

• Template??
• ?C??two-level language
• metaprogram
• ???????-gt??????,?generic programming
• ?????
• ???????
• ?????,?????? partial evaluation
• ???????
• Active libraries,?????????,????????
• ????,?policy(traits)?????????
• ????????
• ??template class??template function

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C Generic Programming(?)

• ????
• ????????,???logic-programming?,?compile-time?????
  ?????,??
• ???????
• if/else,loop,switch
• ?type???????????(??)
• ??????
• ???compile-time error,???runtime error
• ?????? ???
• ????????????,????patterns

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Template?? class template

• templatelttypename T, size_t MAX_ELEMS 8 gt
• class Array
• public
• T operator(size_t n)
• if (n lt 0 ngtMAX_ELEMS) throw "Out of bounds!
  "
• return m_rgn
• protected
• T m_rgMAX_ELEMS

?? Arrayltlong, 8gt a1 Arrayltchar, 200gt a2
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Template?? ????template specialization

• templateltgt
• class Arrayltchar, 256gt
• public
• char operator(size_t n)
• if (n lt 0 ngt256) throw "Out of bounds!"
• return m_szn
• bool operator (const Arrayltchar, 256gt rhs)
• return strcmp(m_sz, rhs.m_sz) 0
• protected
• char m_sz256

15
Template?? ?????? partial template
specialization

• templateltsize_t MAX_ELEMSgt
• class Arrayltchar , MAX_ELEMSgt
• public
• T operator(size_t n)
• if (n lt 0 ngtMAX_ELEMS) throw "Out of
  bounds!"
• return m_szn
• bool operator (const Arrayltchar, MAX_ELEMSgt
  rhs)
• return strcmp(m_sz, rhs.m_sz) 0
• protected
• T m_szMAX_ELEMS
• Visual C 6?????????

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Template?? ????function template
????,compile-time???

• template lt class T gt
• void Swap(T a, Tb)
• T temp a
• a b
• b temp
• template ltclass Tgt
• T min(T a, T b)
• return a lt b ? a b

????,runtime???
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Template?? ??????generalized
functors(function objects)

• functor???operator()?C??,??????????,????????,??
  ????????,?????(value semantic)?????template
  class,?????
• template lt typename ResultType gt
• class Functor
• public
• ResultType operator()()
• // other member function
• private
• // implementation
• ??
• Functorltintgt MyFunctor(val1)
• int Result MyFunctor()

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Template?? ??runtime?if/else

• // Class declarations
• templateltbool Cgt
• class ConditionProcess
• class ConditionProcess lttruegt
• public
• static inline void f()
• statement1 // true case
• class ConditionProcess ltfalsegt
• public
• static inline void f()
• statement2 // false case
• // Replacement for 'if/else' statement
• ConditionProcess ltconditiongtf()

if (condition) statement1 else
statement2
Compile-time????condition??
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Template?? ??runtime?switch

• // Class declarations
• templateltint Igt
• class SwitchProcess
• public
• static inline void f() default-statement
• class SwitchProcess ltvalue1gt
• public
• static inline void f() statement1
• class SwitchProcess ltvalue2gt
• public
• static inline void f() statement2
• // Replacement for switch(i) statement
• SwitchProcess ltIgtf()

int i switch(i) case value1
statement1 break case value2
statement2 break default
default-statement break
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Template?? ??runtime?do??

• templateltint Igt
• class DoProcess
• private
• enum go (I-1) ! 0
• public
• static inline void f()
• statement
• DoProcess ltgo ? (I-1) 0gtf()
• // Specialization provides base case for
  recursion
• class DoProcess lt0gt
• public
• static inline void f()
• // Equivalent loop code
• DoProcess ltNgtf()

int i N do statement while (--i gt 0)
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Template?? ??runtime?????

• templateltint Ngt
• class countBits
• enum
• bit3 (N 0x08) ? 1 0,
• bit2 (N 0x04) ? 1 0,
• bit1 (N 0x02) ? 1 0,
• bit0 (N 0x01) ? 1 0
• public
• enum nbits bit0bit1bit2bit3
• int i countBitslt13gtnbits

int countBits(int N) int bit3 (N 0x08)
? 1 0, bit2 (N 0x04) ? 1 0,
bit1 (N 0x02) ? 1 0, bit0 (N
0x01) ? 1 0 return bit0bit1bit2bit3
int i countBits(13)
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Template?? ?? Compile-time functions

• ????
• ?????enum??
• ???????,???????????
• ????????,??????????
• ???????????
• ????????,??????
• ??
• sin x x - x3/3! x5/5! - x7/7!
• ??????pow(x,y),?x?y??

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Template?? ??pow(x,y)

• templateltint X, int Ygt
• struct ctime_pow
• enum result Xctime_powltX, Y-1gtresult
• templateltint Xgt
• struct ctime_powltX, 0gt
• enum result 1
• ??
• const int z ctime_powlt5,3gtresult

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Trait??

• ??????,???????????????(type),?????(data)
• ?????????,??????????????????,?????trait
  class?????????
• ????
• Average_type(T) -gt T
• Average_type(int) -gt float
• Trait???Average???

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Partial evaluation

• ?????????????
• ???????????
• ???????????
• ??,????????

26
Template?? ???????

• ?????????????
• templateltsize_t MAX_LENgt
• class String public Arrayltchar, MAX_LEN1gt
• public
• // additional functionality
• bool operator(const StringltMAX_LENgt rhs)
• return strcmp(m_rg, rhs.m_rg) 0

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Template?? ?????????

• ??????????????????
• ??????,??????
• templatelttypename Base, typename Policy1gt
• class Deriving public BaseltPolicy1gt

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C as a two-level language

• ?type??first-class value???
• ??
• ???? ?????
• typedef T T_average
• ???
• typedef T_average T
• ????????

29
Template?? typelistfrom Modern C Design

• ??????????
• template ltclass T, class Ugt
• struct Typelist
• typedef T Head
• typedef U Tail

• ??Length??
• template ltclass TListgt struct Length
• template ltgt struct LengthltNullTypegt
• enum value 0
• template ltclass T, class Ugt
• struct Lengthlt TypelistltT, Ugt gt
• enum value 1 LengthltUgtvalue
  

• typelist????
• Length
• TypeAt
• IndexOf
• Append
• Erase
• Replace
• MostDerived
• ...

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Template?? typelist(??)

• typelist??
• define TYPELIST_1(T1) TypelistltT1, NullTypegt
• define TYPELIST_2(T1, T2) TypelistltT1,
  TYPELIST_1(T2) gt
• define TYPELIST_3(T1, T2, T3) TypelistltT1,
  TYPELIST_2(T2, T3) gt
• template ltclass T1, class T2, template ltclassgt
  class Unitgt
• class GenScatterHierarchyltTypelistltT1, T2gt,
  Unitgt
• public GenScatterHierarchyltT1, Unitgt
• , public GenScatterHierarchyltT2, Unitgt
• template ltclass AtomicType, template ltclassgt
  class Unitgt
• class GenScatterHierarchy public
  UnitltAtomicTypegt
• template lttemplate ltclassgt class Unitgt
• class GenScatterHierarchyltNullType, Unitgt

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Template?? typelist(??)

• GenScatterHierarchy??
• template ltclass Tgt
• class Holder
• T m_value

typedef GenScatterHierarchy lt TYPELIST_3(int,
string, CustomClass), Holder gt MyTypeTree
32
Template?????? ????????
templatelttypename T, typename Derivinggt class
Array public ... bool operatorlt(const
ArrayltTgt rhs) return static_castltDeriving
gt(this)-gt Compare(rhs) lt 0 bool
operatorgt(const ArrayltTgt rhs) return
static_castltDeriving gt(this)-gt Compare(rhs) gt
0 bool operator(const ArrayltTgt rhs)
return static_castltDeriving gt(this)-gt Compare(
rhs) 0

• templatelttypename Tgt
• class Array
• public
• virtual int Compare(const ArrayltTgtrhs)0
• bool operatorlt(const ArrayltTgt rhs)
• return this-gtCompare(rhs) lt 0
• bool operatorgt(const ArrayltTgt rhs)
• return this-gtCompare(rhs)gt 0
• bool operator(const ArrayltTgt rhs)
• return this-gtCompare(rhs) 0

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policy

• Aliases strategy, behavior class, trait, aspect
• ???????????????,???????????,??????????,???????????
  
• ?????????????

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Policy(??)

• ???policy??????????
• ???????????????????,???policy class???,??
• ????
• ????
• policy????????
• ?????,???????????,????????(RefCountPolicy)?????(St
  oragePolicy)
• policy??host??????runtime????,????compile-time????

35
Policy(??)

• ???????policy class
• ????compile-time?host class????
• ??
• templatelt typename ThreadingModelSingleThreaded
  gt
• class Widget
• templatelttemplateltclass Createdgt class
  CreationPolygt
• class WidgetManager

36
Policy(??)

• Policy??,?mn?????nm???,??
• template
• lt
• class T,
• template ltclassgt class CheckingPolicy,
• templateltclassgt ThreadingModel
• gt
• class SmartPtr
• typedef SmartPtrltWidget, EnsureNotNull,
  SingleThreadedgt SafeWidgetPtr
• templateltclass Tgtstruct EnsureNotNull
• static void Check(T ptr)
• if (!ptr) ptr GetDefaultValue()

37
Policy(??)

• ?????Policy???
• ?compile-time??host class,????????????,??generic
• ??????????,??policy????????,?class-level???
• ??????????????,???????policy,???policy???
• ????hook???,????????policy class,???????????
• ??
• ???????policy??????,??????????????????

38
Visitor??(GoF)
39
Visitor????
????
Visitor??
EleVisitor
ElementAVisitor
ElementBVisitor
ConcreteElementA Accept(EleVisitor) OperationA
ConcreteElementB Accept(EleVisitor) OperationB
MyConcreteVisitor
40
Lazy??

• Lazy Initialization,??????????
• Singleton SingletonInstance()
• if (!pInstance)
• pInstance new Singleton
• return pInstance
• COW(Copy on write),??????????
• Lazy ProtocolDCOM??

41
Double-Checked Locking Pattern

• ??mutex???Mutex??,?????pInstance???????,?????
• Singleton SingletonInstance()
• Lock guard(mutex)
• if (!pInstance)
• pInstance new Singleton
• return pInstance

42
Double-Checked Locking Pattern(??)

• ??????????,????new??????,?????????????,??
• Singleton SingletonInstance()
• if (!pInstance)
• Lock guard(mutex)
• pInstance new Singleton
• return pInstance

• ??race condition????

43
Double-Checked Locking Pattern(??)

• Double-Checked Locking Pattern
• Singleton SingletonInstance()
• if (!pInstance)
• Lock guard(mutex)
• if (!pInstance)
• pInstance new Singleton
• return pInstance

44
Table-driven pattern

• ??runtime switch
• ???????????CShape??????,?????
• ReadWord(stream, typeid)
• switch (typeid)
• case Line_ID
• pObj (CShape )new CLine
• pObj-gtLoad(stream)
• break
• case Poly_ID
• pDoc.Add(pObj)

45
Table-driven pattern(?)

• ?????(typeid, fnCreator)
• ??typeid???????,??????,??????
• ReadWord(stream, typeid)
• FnCreator fn TableInstance().Lookup(typeid)
• pObj fn()
• pObj-gtLoad(stream)
• pDoc.Add(pObj)
• ?MFC/ATL????table-driven???
• ????????double-dispatch??multi-dispatch??

46
??????union

• Union??????
• Discriminated union tag union
• ??VARIANT
• ???????????union,????????union???????
• ??Java
• ????????
• ?????
• ???????
• ????
• ????????????(OO)
• ??Effective Java

47
????????union
48
??enum??

• Enum?????
• ??????????????
• ????,??enum??????????
• ??????????
• ?????(?????)?????
• typesafe enum pattern, from Effective Java
• ????????????????,????????????????,???????final?,?
  ?????????????????

49
framework

• ????
• ???? gt????
• ????????
• ???
• ??????,??????????????????
• ??????framework
• ????????framework,??MMC
• ??????framework,??MFC

50
??????framework

• ??
• ??????????????
• ???????
• ??????
• ??
• ??????
• ????,??????????
• ????
• ???????????
• ???????????
• ????????
• ??????????

51
??????framework

• ??
• ??????,??????????,????????
• ??????????
• ????
• ???????????
• ???????????????

52
????????????????

• ??
• ???????????????????,??????????????????
• ???generic programming????,?????????????????(?????
  )
• ????
• ?????????? runtime???
• ??????????,???????????????,?????????????????
• ????????framework??

53
Framework??

• ???????framework

IFrameSite
SnapIn DLL
SnapIn DLL
SnapIn DLL
ISnapInfo
SnapIn??
SnapIn??
SnapIn??
SnapIn??
FrameSite
FrameSite
FrameSite
Snap-In???
Security???
Database???
UI???
54
????????(?)

• ?????????,???????????????,???
• ?????????
• ????????
• ??????
• ????????????????,???????????
• ?????
• ?????????????????????????
• ???????
• ????

55
????????(?)

• ?????
• ???????,?????????
• ?????C/C
• ??????????
• ??????????
• facade??
• ????
• ?????????????
• ?????
• out??????????????size?
• ?????????????,???????????

56
????????(?)

• ??????
• ?????,?????
• policy??????????
• ????????????????????,??????????
• ?????????????????????
• ??????????????????
• ????????
• ????????compile-time????
• ????????
• ????????

57
????????(?)

• ???????
• ???????????
• ???? ????????
• ??functor??????
• ??(??)?????????
• ???????
• ????
• ?????
• ??????????,????????
• ??????policy????,?????????
• ???policy???,????????????

58
????????(?)

• ?????
• ??????,??assert??
• ?????
• ????????????
• ?????
• ????????
• ??
• ????

59
????????(?)

• ??MFC/ATL
• MFC
• ?????????????
• ??????C??,?Win32?????
• ??????????,????
• ?????patterns,??Windows????
• ???????????
• ?Wizard????????
• ATL
• ???generic programming???????
• ????
• ??????

60
??

• C??
• COM??
• COM??
• COM
• Design Patterns
• ??????