Question

I have the following two methods

Method 1

public String[] getSongIds(String whereClause) 
    {
        String countQuery = "SELECT  songid FROM TABLE_INDEX WHERE " + whereClause;
        Cursor cursor = db.rawQuery(countQuery, null);
        int cursorSize = cursor.getCount();

        int[] songIds = new int[cursorSize];
        int count=0;
        if (cursor != null ) {
            if (cursor.moveToFirst()){
                   do{
                       songIds[count] = cursor.getInt(cursor.getColumnIndex("songid"));
                      count++;
                   }while(cursor.moveToNext());
                }
        }
        cursor.close();
        db.close();
        return getSongTitles(songIds);
    }

Method 2

private String[] getSongTitles(int[] songIds) {

    /some algorithm
    return songTitles;

}

Method 1 is called from a different package. Method 1 runs a query against SQLite database and calls the 2nd method. I need to catch the exception often cause by executing the SQLite query in method 1. Preferably returning (-1) or something so I can display a message to user from the package where these methods were initially called. So I want method 1 to avoid calling method 2 if there was a (wrong input) SQL exception, instead return something back to the other package

p.s I saw couple ways to catch this exception but weren’t satisfied with their approach. Want to know whats the best way to deal with this. cheers

Answer 1

Catch the exception, wrap it in a custom one, and throw it:

public String[] getSongIds(String whereClause) throws FetchSongException {
  String countQuery = "SELECT  songid FROM TABLE_INDEX WHERE " + whereClause;
  try {
    Cursor cursor = db.rawQuery(countQuery, null);
    int cursorSize = cursor.getCount();

    int[] songIds = new int[cursorSize];
    int count=0;
    if (cursor != null) {
      if (cursor.moveToFirst()) {
        do {
          songIds[count] = cursor.getInt(cursor.getColumnIndex("songid"));
          count++;
        } while(cursor.moveToNext());
      }
      cursor.close(); // you should put this in a finally block
      db.close();
      return getSongTitles(songIds);
    }
  } catch (SQLException sqle) {
    throw new FetchSongException("Unable to fetch song ids.", sqle);
  }
}

Then, whoever calls getSongIds needs to catch this new exception:

try {
  String[] result = getSongsIds("something");
} catch (FetchSongException e) {
  // Display user message with e.getMessage();
}