hazy_model.h

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#ifndef HAZY_MODEL_H
#define HAZY_MODEL_H

#include "model.h"

#include <sstream>

struct hazy_model {
  struct model &_model;
  enum strategy { LAZY_NAIVE, EAGER_NAIVE,LAZY_HAZY, EAGER_HAZY } _strategy;
  double low_water, high_water;
  bool model_is_in_db;
  bool test_and_set_model_in_db() { bool ret = model_is_in_db; model_is_in_db = true; return ret; }
  void invalidate_db_model() { model_is_in_db = false; }
  

  bool isEager()  { return (_strategy == EAGER_NAIVE || _strategy == EAGER_HAZY); }
  bool isLazy ()  { return (_strategy == LAZY_NAIVE  || _strategy == LAZY_HAZY); }
  bool isHazy()   {return (_strategy == EAGER_HAZY || _strategy == LAZY_HAZY);}
  bool isNaive()  { return (_strategy == EAGER_NAIVE || _strategy == LAZY_NAIVE); }
  

  static bool isEager(strategy s) { return (s == EAGER_NAIVE || s == EAGER_HAZY); }
  static bool isLazy(strategy s)  {return (s == LAZY_NAIVE || s == LAZY_HAZY);}
  static bool isHazy(strategy s)  { return (s == EAGER_HAZY || s == LAZY_HAZY); } 
  static bool isNaive(strategy s) {return (s == EAGER_NAIVE || s == LAZY_NAIVE);}
  

hazy_model(struct model &model, strategy s) : _model(model), _strategy(s), 
    low_water(0.0), high_water(0.0), model_is_in_db(false) { }
};

class UnknownStrategyException : public std::exception {
  std::string _filename, _msg;
  int _line;
 public:
  UnknownStrategyException(const char* file, int line, const char *msg) {
    _filename = std::string(file);
    _line     = line;
    _msg      = std::string(msg);
  }
  virtual ~UnknownStrategyException() throw() { } 
  
  virtual const char* what() const throw() {
    std::ostringstream s;
    s << "[Unknown Strategy Exception @ " << _filename << ":" << _line << "] msg: " << _msg;
    return s.str().c_str();
  }
  
};

#endif

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