TAO/docs/tutorials/Quoter/RTCORBA/Stock_Database.h

   1 /**
   2  * @file Stock_Database.h
   3  * @author Shanshan Jiang <shanshan.jiang@vanderbilt.edu>
   4  * @author William R. Otte <wotte@dre.vanderbilt.edu>
   5  * @author Douglas C. Schmidt <schmidt@dre.vanderbilt.edu>
   6  */
   7
   8 #ifndef STOCK_DATABASE_H_
   9 #define STOCK_DATABASE_H_
  10
  11 // ACE headers
  12 #include "ace/Task.h"
  13
  14 // TAO headrs
  15 // #include "tao/orbconf.h"
  16
  17 // STL headers
  18 #include <map>
  19 #include <string>
  20
  21 /**
  22  * @class Stock_Database
  23  * @brief This class is used to install, update and publish the information of
  24  * all the stocks. It uses the singleton design pattern.
  25  * The parameter type may be any type that has a method called "updated_stocks" and
  26  * accepts a std::vector of std::strings as an argument.
  27  */
  28 template <typename CALLBACK>
  29 class Stock_Database : public ACE_Task_Base
  30 {
  31 public:
  32   /// Default constructor
  33   /// Initializes the stock database with MSFT, IBM, and INTEL.
  34   /// @param the rate at which to perform updates
  35   Stock_Database (u_int rate = 1);
  36
  37   /// Constructor.
  38   /// @param file The name of a file to read initial stocks and values from.
  39   Stock_Database (const char *file, u_int rate = 1);
  40
  41   typedef std::map <std::string,
  42                     unsigned int> Init_Map;
  43
  44   /// Constructor
  45   /// @param stockmap  A map containing stocks and initial values.  An initial value
  46   /// of 0 will be assigned a random start value.
  47   Stock_Database (const Init_Map &stockmap, u_int rate = 0);
  48
  49   typedef std::string Cookie;
  50
  51   /**
  52    * Register a callback object with the database. The callback object must have
  53    * the () operator defined accepting a std::vector of strings as the argument.
  54    * @returns A cookie to identify the registration
  55    */
  56   Cookie register_callback (CALLBACK &obj);
  57
  58   /**
  59    * Removes a callback from the notification queue.
  60    * @returns false if the provided cookie is not found.
  61    */
  62   bool remove_callback (const Cookie &);
  63
  64   /// Raised if an invalid stock name is requested.
  65   class Invalid_Stock {};
  66
  67   struct StockInfo
  68   {
  69     StockInfo (void)
  70       : name_(""), high_ (0), low_ (0), last_ (0)
  71     {};
  72
  73     StockInfo (const std::string name)
  74       : name_ (name), high_ (0), low_(0), last_(0)
  75     {};
  76
  77     std::string name_;
  78     int high_;
  79     int low_;
  80     int last_;
  81   };
  82
  83   /**
  84    * Create a StockInfo object stored in the database with the given name.
  85    *
  86    * @param name The name of the stock.
  87    * @return A StockInfo object.
  88    */
  89   StockInfo get_stock_info (const char *name);
  90
  91   /**
  92    * This function is used to calculate the new high, low and last values
  93    * for each stock in the stock database randomly.
  94    */
  95   virtual int svc (void);
  96
  97   /// Change the rate at which database updates are made
  98   void update_rate (u_int rate);
  99
 100   /// Launch the active object
 101   void start (void);
 102
 103   /// Stop the active object
 104   void stop (void);
 105
 106   typedef std::map <std::string, StockInfo> Stock_Map;
 107
 108   /// This method is not intended to be called by clients of this class,
 109   /// it is public only by necessity.
 110   virtual int handle_signal (int signum,
 111                              siginfo_t * = 0,
 112                              ucontext_t * = 0);
 113
 114   typedef std::map <Cookie, CALLBACK *> Callback_Map;
 115
 116 private:
 117   /// The filname initialized from, if any.
 118   const std::string filename_;
 119
 120   /// Keep track of the stock names and information about them.
 121   Stock_Map stock_map_;
 122
 123   /// Lock to protect concurrent access to the <stock_map_>.
 124   ACE_RW_Thread_Mutex lock_;
 125
 126   /// Rate at which updates are made.
 127   u_int rate_;
 128
 129   Callback_Map callbacks_;
 130
 131   bool active_;
 132 };
 133
 134 #include "Stock_Database.tpp"
 135
 136 //typedef ACE_Singleton<Stock_Database, TAO_SYNCH_MUTEX> Stock_Database_Singleton;
 137 //#define STOCK_DATABASE Stock_Database_Singleton::instance()
 138
 139 #endif  // !defined STOCK_DATABASE_H_