src/prediction/predictor_interface.h

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#ifndef MOZC_PREDICTION_PREDICTOR_INTERFACE_H_
#define MOZC_PREDICTION_PREDICTOR_INTERFACE_H_

namespace mozc {

class Segments;

class PredictorInterface {
 public:
  // return suggestions.
  // You may need to change the behavior according to the
  // Segments::request_type flag
  // SUGGESTION: automatic suggestions
  // PREDICTION: invoked only when user pushes "tab" key.
  // less aggressive than SUGGESTION mode.
  virtual bool Predict(Segments *segments) const = 0;

  // Hook(s) for all mutable operations
  virtual void Finish(Segments *segments) {}

  // Revert the last Finish operation
  virtual void Revert(Segments *segments) {}

  // clear all history data of UserHistoryPredictor
  virtual bool ClearAllHistory() { return true; }

  // clear unused history data of UserHistoryPredictor
  virtual bool ClearUnusedHistory() { return true; }

  // Sync user history to local disk.
  virtual bool Sync() { return true; }

  // Reload user history data from local disk.
  virtual bool Reload() { return true; }

 protected:
  // don't allow users to call constructor and destructor
  PredictorInterface() {}
  virtual ~PredictorInterface() {}
};

// factory for making "default" predictors
class PredictorFactory {
 public:
  // return singleton object
  static PredictorInterface *GetPredictor();
  static PredictorInterface *GetUserHistoryPredictor();
  static PredictorInterface *GetDictionaryPredictor();

  // dependency injection for unittesting
  static void SetPredictor(PredictorInterface *predictor);
  static void SetUserHistoryPredictor(PredictorInterface *predictor);
  static void SetDictionaryPredictor(PredictorInterface *predictor);

 private:
  PredictorFactory() {}
  ~PredictorFactory() {}
};
}  // namespace mozc

#endif  // MOZC_PREDICTION_PREDICTOR_INTERFACE_H_