Question

How would you write ToUpper() if it didn’t exist? Bonus points for i18n and L10n

Curiosity sparked by this: http://thedailywtf.com/Articles/The-Long-Way-toUpper.aspx

Answer 1

1. I download the Unicode tables
2. I import the tables into a database
3. I write a method upper().

Here is a sample implementation 😉

public static String upper(String s) {     if (s == null) {         return null;     }      final int N = s.length(); // Mind the optimization!     PreparedStatement stmtName = null;     PreparedStatement stmtSmall = null;     ResultSet rsName = null;     ResultSet rsSmall = null;     StringBuilder buffer = new StringBuilder (N); // Much faster than StringBuffer!     try {         conn = DBFactory.getConnection();         stmtName = conn.prepareStatement('select name from unicode.chart where codepoint = ?');         // TODO Optimization: Maybe move this in the if() so we don't create this         // unless there are uppercase characters in the string.         stmtSmall = conn.prepareStatement('select codepoint from unicode.chart where name = ?');         for (int i=0; i<N; i++) {             int c = s.charAt(i);             stmtName.setInt(1, c);             rsName = stmtName.execute();             if (rsName.next()) {                 String name = rsName.getString(1);                 if (name.contains(' SMALL ')) {                     name = name.replaceAll(' SMALL ', ' CAPITAL ');                      stmtSmall.setString(1, name);                     rsSmall = stmtSmall.execute();                     if (rsSmall.next()) {                         c = rsSmall.getInt(1);                     }                      rsSmall = DBUtil.close(rsSmall);                 }             }             rsName = DBUtil.close(rsName);         }     }     finally {         // Always clean up         rsSmall = DBUtil.close(rsSmall);         rsName = DBUtil.close(rsName);         stmtSmall = DBUtil.close(stmtSmall);         stmtName = DBUtil.close(stmtName);     }      // TODO Optimization: Maybe read the table once into RAM at the start     // Would waste a lot of memory, though :/     return buffer.toString(); } 

😉

Note: The unicode charts which you can find on unicode.org contain the name of the character/code point. This string will contain ‘ SMALL ‘ for characters which are uppercase (mind the blanks or it might match ‘SMALLER’ and the like). Now, you can search for a similar name with ‘SMALL’ replaced with ‘CAPITAL’. If you find it, you’ve found the captial version.