Line data    Source code

       1              : #ifndef LOADNEWSOPERATION_H
       2              : #define LOADNEWSOPERATION_H
       3              : 
       4              : #include <QObject>
       5              : #include <QList>
       6              : 
       7              : #include "DBOperation.h"
       8              : #include "../models/FeedItem.h"
       9              : #include "../models/NewsItem.h"
      10              : 
      11              : /*!
      12              :     \brief Loads a batch of NewsItems.
      13              :  */
      14              : class LoadNewsOperation : public DBOperation
      15              : {
      16              :     Q_OBJECT
      17              : public:
      18              :     
      19              :     enum LoadMode {
      20              :         Error = -1,   // Runtime error
      21              :         Initial = 0,  // Loads loadLimit items from the bookmark, plus loadlimit items above bookmark
      22              :         Append,       // Appends loadLimit items (load next)
      23              :         Prepend       // Prepends loadLimit items (load previous)
      24              :     };
      25              :     
      26              :     /*!
      27              :         \param parent    The manager
      28              :         \param feedItem  The feed item to grab
      29              :         \param mode      Type of load operation (see above)
      30              :         \param loadLimit Max number of news items to load
      31              :      */
      32              :     explicit LoadNewsOperation(OperationManager *parent, FeedItem* feedItem, LoadMode mode, int loadLimit = 15);
      33              :     
      34              :     virtual ~LoadNewsOperation();
      35              : 
      36              :     static LoadMode stringToMode(QString modeString);
      37              :     static QString modeToString(LoadMode mode);
      38              :     
      39              : public slots:
      40              :     virtual void execute();
      41              :     
      42              :     /*!
      43              :         \return The Feed associated with this load.
      44              :      */
      45            0 :     inline FeedItem* getFeedItem() { return feedItem; }
      46              :     
      47              :     /*!
      48              :         \return Returns the operational mode.
      49              :      */
      50            7 :     inline LoadNewsOperation::LoadMode getMode() { return mode; }
      51              :     
      52              :     /*!
      53              :         \return List of items that this load appended.
      54              :      */
      55           13 :     inline QList<NewsItem*>& getAppendList() { return listAppend; }
      56              :     
      57              :     /*!
      58              :         \return List of items that this load prepended.
      59              :      */
      60            0 :     inline QList<NewsItem*>& getPrependList() { return listPrepend; }
      61              :     
      62              :     /*!
      63              :         \return Max number of items to load (specified as loadLimit in constructor.)
      64              :      */
      65            7 :     inline int getLoadLimit() const { return loadLimit; }
      66              :     
      67              : protected slots:
      68              : 
      69              :     /*!
      70              :         \brief Extracts news items from a database query.
      71              :         \param query  Database query containing zero or more News Items.
      72              :         \param list   The list of items items we just created.
      73              :      */
      74              :     void queryToNewsList(QSqlQuery& query, QList<NewsItem*>* list);
      75              :     
      76              :     /*!
      77              :         \brief Call this during the initial load of a feed.
      78              :         \return id of feed's bookmark.
      79              :      */
      80              :     qint64 getBookmarkID();
      81              :     
      82              :     /*!
      83              :         \brief Finds the very first item available in this feed, loaded or not. This is
      84              :                used to determine whether or not to display the top bookmark.
      85              :         \return id of the first item in the entire feed.
      86              :      */
      87              :     virtual qint64 getFirstNewsID();
      88              :     
      89              :     bool doAppend(qint64 startId);
      90              :     
      91              :     bool doPrepend(qint64 startId);
      92              :     
      93              :     /*!
      94              :         \brief Performs the actual query and loads the results into the appropriate list
      95              :         \param startId ID to start with
      96              :         \param append Which direction and which list to load into
      97              :         \return True if successful, false on an error
      98              :      */
      99              :     virtual bool executeLoadQuery(qint64 startId, bool append);
     100              : 
     101              :     // Returns the next ID after the last item in the feed's news list, or -1
     102              :     qint64 getStartIDForAppend();
     103              : 
     104              :     // Returns the first ID in the feed's news list, or -1
     105              :     qint64 getStartIDForPrepend();
     106              :     
     107              : protected:
     108              : 
     109              :     // Feed we're adding to.
     110              :     FeedItem* feedItem;
     111              :     
     112              :     // List of items we appended.
     113              :     QList<NewsItem*> listAppend;
     114              :     
     115              :     // List of items we prepended.
     116              :     QList<NewsItem*> listPrepend;
     117              :     
     118              :     // True if we're appending.
     119              :     LoadMode mode;
     120              :     
     121              :     // Max # of news items to add.
     122              :     int loadLimit;
     123              : };
     124              : 
     125              : #endif // LOADNEWSOPERATION_H