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  1. #include <iostream>
  2. #include <iterator>
  3. #include <algorithm>
  4. #include <vector>
  5. #include <tr1/memory>
  6. #include <tr1/functional>
  7.  
  8.  
  9. struct Data
  10. {
  11.     int A, B, C;
  12. };
  13.  
  14.  
  15. class DataSpecification
  16. {
  17. public:
  18.     virtual bool IsSatisfiedBy(Data&) const = 0;
  19. };
  20.  
  21. typedef std::tr1::shared_ptr<DataSpecification> DataSpecificationPtr;
  22.  
  23.  
  24. class Validator
  25. {
  26. public:
  27.     void AddSpecification(DataSpecificationPtr spec)
  28.     {
  29.         specs_.push_back(spec);
  30.     }
  31.  
  32.     bool IsValid(Data& data)
  33.     {
  34.         using std::tr1::placeholders::_1;
  35.         return specs_.end() != std::find_if(specs_.begin(), specs_.end(), 
  36.             std::tr1::bind(&DataSpecification::IsSatisfiedBy, _1, data));
  37.     }
  38. private:
  39.     std::vector<DataSpecificationPtr> specs_;
  40. };
  41.  
  42.  
  43. class DataLoader
  44. {
  45. public:
  46.     DataLoader(bool breakIfInvalid, const Validator& validator) :
  47.         validator_(validator),
  48.         breakIfInvalid_(breakIfInvalid), 
  49.         a(0), b(1), c(2)
  50.     {
  51.  
  52.     }
  53.  
  54.     template<typename OutIter>
  55.     void Load(OutIter out)
  56.     {
  57.         while(HasNext())
  58.         {
  59.             Data data = LoadNext();
  60.             if (!validator_.IsValid(data))
  61.             {
  62.                 if (breakIfInvalid_)
  63.                     break;
  64.                 else
  65.                     continue;
  66.             }
  67.             out++ = data;
  68.         }
  69.     }
  70.  
  71. private:
  72.  
  73.     bool HasNext()
  74.     {
  75.         return a < 10;
  76.     }
  77.  
  78.     Data LoadNext()
  79.     {
  80.         Data d;
  81.         d.A = a++;
  82.         d.B = b++;
  83.         d.C = c++;
  84.         return d;
  85.     }
  86.  
  87.     Validator validator_;
  88.     bool breakIfInvalid_;
  89.     int a, b, c;
  90. };
  91.  
  92.  
  93. class AGreaterMin : public DataSpecification
  94. {
  95. public:
  96.     AGreaterMin(int minA) : min_(minA){}
  97.  
  98.     bool IsSatisfiedBy(Data& data) const
  99.     {
  100.         return data.A > min_;
  101.     }
  102.     int min_;
  103. };
  104.  
  105. class BGreaterMin : public DataSpecification
  106. {
  107. public:
  108.     BGreaterMin(int minB) : min_(minB){}
  109.  
  110.     bool IsSatisfiedBy(Data& data) const
  111.     {
  112.         return data.B > min_;
  113.     }
  114.     int min_;
  115. };
  116.  
  117.  
  118. template<typename DataContainer>
  119. void PrintData(const DataContainer& c)
  120. {
  121.     typedef typename DataContainer::const_iterator Iter;
  122.     for (Iter it = c.begin(), end = c.end(); it != end; ++it)
  123.         std::cout << it->A << " " << it->B << " "  << it->C << "\n";
  124. }
  125. int main()
  126. {
  127.     std::vector<Data> data;
  128.     Validator v;
  129.     v.AddSpecification(DataSpecificationPtr(new AGreaterMin(5)));
  130.     v.AddSpecification(DataSpecificationPtr(new BGreaterMin(7)));
  131.  
  132.  
  133.     DataLoader loader1(false, v);
  134.     loader1.Load(std::back_inserter(data));
  135.     PrintData(data);
  136.  
  137.     data.clear();
  138.     std::cout << "Break if invalid:\n";
  139.     DataLoader loader2(true, v);
  140.     loader2.Load(std::back_inserter(data));
  141.     PrintData(data);
  142. }
Success #stdin #stdout 0s 2864KB
comments (?)
stdin
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Standard input is empty
stdout
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6 7 8
7 8 9
8 9 10
9 10 11
Break if invalid:
https://ideone.com/lbY1x
language:
C++ (gcc 8.3)
created:
12 years ago
visibility:
public

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