concordia-library/concordia/hash_generator.hpp

#ifndef HASH_GENERATOR_HDR
#define HASH_GENERATOR_HDR

#include <string>
#include <map>
#include <vector>
#include <boost/shared_ptr.hpp>
#include <boost/algorithm/string/predicate.hpp>
#include "concordia/word_map.hpp"
#include "concordia/common/config.hpp"
#include "concordia/sentence_anonymizer.hpp"
#include "concordia/concordia_config.hpp"
#include "concordia/concordia_exception.hpp"


/*!
  Class for generating a sentence hash. The hash is generated from a sentence
  given in raw string. String is first anonymized and tokenized. After these
  operations, each token is coded as an integer, according to WordMap.
  Resulting hash is a vector of integers.
  
  Sentence hashed is used when adding a sentence to index and during searching.
  
  HashGenerator holds an instance of WordMap, used to code tokens as integers
  and SentenceAnonymizer, used to preprocess the sentence string.

*/

class HashGenerator {
public:
    /*!
      Constructor.
      \param config pointer to current config object
    */
    explicit HashGenerator(boost::shared_ptr<ConcordiaConfig> config)
                                            throw(ConcordiaException);

    /*! Destructor.
    */
    virtual ~HashGenerator();

    /*!
      Generates hash of a sentence.
      \param sentence sentence to generate hash from
      \returns vector of integers
    */
    std::vector<INDEX_CHARACTER_TYPE> generateHash(const std::string & sentence)
                                throw(ConcordiaException);

    /*!
      Generates vector of tokens from a sentence. This method is internally
      used by generateHash. However, for the sake of concordiaSearch
      (see \ref tutorial1_3), the vector of tokens resulting from sentence
      anonymizing and tokenization is also needed.
      \param sentence sentence to tokenize
      \returns vector of tokens
    */
    std::vector<std::string> generateTokenVector(const std::string & sentence);


    /*!
        Saves the contents of current WordMap to HDD.
    */
    void serializeWordMap();

    /*!
        Clears word map.
    */
    void clearWordMap();

private:
    boost::shared_ptr<WordMap> _wordMap;

    boost::shared_ptr<SentenceAnonymizer> _sentenceAnonymizer;

    std::string _wordMapFilePath;
};

#endif