presage  0.8.7
contextTracker.h
Go to the documentation of this file.
00001 
00002 /******************************************************
00003  *  Presage, an extensible predictive text entry system
00004  *  ---------------------------------------------------
00005  *
00006  *  Copyright (C) 2008  Matteo Vescovi <matteo.vescovi@yahoo.co.uk>
00007 
00008     This program is free software; you can redistribute it and/or modify
00009     it under the terms of the GNU General Public License as published by
00010     the Free Software Foundation; either version 2 of the License, or
00011     (at your option) any later version.
00012 
00013     This program is distributed in the hope that it will be useful,
00014     but WITHOUT ANY WARRANTY; without even the implied warranty of
00015     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00016     GNU General Public License for more details.
00017 
00018     You should have received a copy of the GNU General Public License along
00019     with this program; if not, write to the Free Software Foundation, Inc.,
00020     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
00021                                                                              *
00022                                                                 **********(*)*/
00023 
00024 
00025 #ifndef PRESAGE_CONTEXTTRACKER
00026 #define PRESAGE_CONTEXTTRACKER
00027 
00028 #ifdef HAVE_CONFIG_H
00029 #include "config.h"
00030 #endif
00031 
00032 #include <iostream>
00033 #include <sstream>
00034 #include <string>
00035 #include <vector>
00036 #include <assert.h>
00037 
00038 #include "contextChangeDetector.h"
00039 
00040 #include "../tokenizer/reverseTokenizer.h"
00041 #include "../charsets.h"
00042 #include "../configuration.h"
00043 #include "../logger.h"
00044 #include "../dispatcher.h"
00045 
00046 #include "../../presageCallback.h"
00047 
00048 class PredictorRegistry;
00049 
00155 class ContextTracker : public Observer {
00156 public:
00157     ContextTracker(Configuration* config,
00158                    PredictorRegistry* predictorRegistry,
00159                    PresageCallback* callback,
00160                    const char[]=DEFAULT_WORD_CHARS,
00161                    const char[]=DEFAULT_SEPARATOR_CHARS,
00162                    const char[]=DEFAULT_BLANKSPACE_CHARS,
00163                    const char[]=DEFAULT_CONTROL_CHARS );
00164     ~ContextTracker();
00165 
00166     const PresageCallback* callback(const PresageCallback* callback);
00167 
00168     bool contextChange();
00169 
00170     std::string getPrefix() const;
00171     std::string getToken (const int) const;
00172 
00173     std::string getSlidingWindowToken(const int index) const;
00174 
00175     std::string getFutureStream() const;
00176     std::string getPastStream  () const;
00177 
00178     bool isCompletionValid(const std::string&) const;
00179 
00180     //eliminate after testing phase
00181     std::string getWordChars()       const;
00182     std::string getSeparatorChars()  const;
00183     std::string getBlankspaceChars() const;
00184     std::string getControlChars()    const;
00185 
00186     std::string toString() const;
00187 
00188     void update();
00189 
00190     virtual void update (const Observable* variable);
00191 
00192     void set_logger (const std::string& value);
00193     void set_sliding_window_size (const std::string& value);
00194 
00195     static const char* LOGGER;
00196     static const char* SLIDING_WINDOW_SIZE;
00197 
00198 private:
00199     std::string wordChars;
00200     std::string separatorChars;
00201     std::string blankspaceChars;
00202     std::string controlChars;
00203 
00204     // REVISIT: this was removed since a tokenizer is created with
00205     // each method invocation that needs it
00206     //ReverseTokenizer tokenizer;
00207 
00208     // utility functions
00209     bool isWordChar      (const char) const;
00210     bool isSeparatorChar (const char) const;
00211     bool isControlChar   (const char) const;
00212     bool isBlankspaceChar(const char) const;
00213 
00214     const PresageCallback* context_tracker_callback;
00215     PredictorRegistry* predictorRegistry;
00216     ContextChangeDetector* contextChangeDetector;
00217     Logger<char> logger;
00218     
00219     Dispatcher<ContextTracker> dispatcher;
00220 };
00221 
00222 #endif // PRESAGE_CONTEXTTRACKER