//specification.h

#pragma once

template<class T>
class Specification
{
public:
 virtual bool IsSatisfiedBy(T candidate) = 0;
 virtual Specification<T>* And(Specification<T>* other) = 0;
 virtual Specification<T>* Or(Specification<T>* other) = 0;
 virtual Specification<T>* Not() = 0;
};

template<class T>
class CompositeSpecification : public Specification<T>
{
public:
 virtual bool IsSatisfiedBy(int candidate) = 0;
 virtual Specification<T>* And(Specification<T>* other);
 virtual Specification<T>* Or(Specification<T>* other);
 virtual Specification<T>* Not();
};

template<class T>
class AndSpecification : public CompositeSpecification<T>
{
public:
 AndSpecification(Specification<T>* x, Specification<T>* y)
 {
  m_one = x;
  m_other = y;
 }
 virtual bool IsSatisfiedBy(int candidate)
 {
  return m_one->IsSatisfiedBy(candidate) && m_other->IsSatisfiedBy(candidate);
 }

private:
 Specification<T>* m_one;
 Specification<T>* m_other;
};

template<class T>
class OrSpecification : public CompositeSpecification<T>
{
public:
 OrSpecification(Specification<T>* x, Specification<T>* y)
 {
  m_one = x;
  m_other = y;
 }
 virtual bool IsSatisfiedBy(int candidate)
 {
  return m_one->IsSatisfiedBy(candidate) || m_other->IsSatisfiedBy(candidate);
 }

private:
 Specification<T>* m_one;
 Specification<T>* m_other;
};

template<class T>
class NotSpecification : public CompositeSpecification<T>
{
public:
 NotSpecification(Specification<T>* x)
 {
  m_wrapped = x;
 }
 virtual bool IsSatisfiedBy(int candidate)
 {
  return !m_wrapped->IsSatisfiedBy(candidate);
 }
private:
 Specification<T> *m_wrapped;
};

//CompositeSpecification
template<class T>
Specification<T>* CompositeSpecification<T>::And(Specification<T>* other)
{
 return new AndSpecification<T>(this, other);
}
template<class T>
Specification<T>* CompositeSpecification<T>::Or(Specification<T>* other)
{
 return new OrSpecification<T>(this, other);
}
template<class T>
Specification<T>* CompositeSpecification<T>::Not()
{
 return new NotSpecification<T>(this);
}

//test.cpp

#include "specification.h"

#include <vector>
#include <algorithm>
using namespace std;

class OddSpecification : public CompositeSpecification<int>
{
public:
 virtual bool IsSatisfiedBy(int candidate)
 {
  return candidate % 2 != 0;
 }
};

class PositiveSpecification : public CompositeSpecification<int>
{
public:
 virtual bool IsSatisfiedBy(int candidate)
 {
  return candidate > 0;
 }
};

int main(int argc, char* argv[])
{
 vector<int> vint;
 for (int i = -5; i < 10; i++)
  vint.push_back(i);

 Specification<int> *oddSpec = new OddSpecification();
 Specification<int> *positiveSpec = new PositiveSpecification();
 Specification<int> *oddAndPositiveSpec = oddSpec->And(positiveSpec);

 for (vector<int>::iterator it = vint.begin(); it != vint.end(); ++it)
 {
  if (oddAndPositiveSpec->IsSatisfiedBy(*it))
   //if (oddSpec->IsSatisfiedBy(*it))
   printf("%d\n", *it);

 }

 delete oddSpec;
 delete positiveSpec;
 delete oddAndPositiveSpec;
 system("PAUSE");
 return 0;
}

//vs2013測試通過