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Groups > comp.lang.java.programmer > #37100

Re: Is this the way to work with try with resources

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ram@zedat.fu-berlin.de (Stefan Ram) writes:

> Patrick Roemer <sangamon@netcologne.de> writes:
>>| By default, only one ResultSet object per Statement object can be open
>>| at the same time. Therefore, if the reading of one ResultSet object is
>
>   Ok. As far as I understand it, the refactoring posted by me
>   does not suffer from violations against this restriction.
>
>   Still, I have revised my code so as to make the try regions
>   for the statements as small as possible in order to make it
>   readably clear that there is no such violation:
>
>   (Note that especially »makeFormatAndContinue()« now is
>   evaluated outside of the scope of »rsTotal«, so now there
>   are no result sets that even have overlapping lifetimes.)
>
> private static java.sql.Statement statement;
> private static int count;
> private static java.lang.String format;
>
> private static void printTotal() 
> { System.out.printf( format, count, "total" );  }
>
> private static void printUnused() 
> throws java.sql.SQLException
> { int countUnused = 0;
>   try( final java.sql.ResultSet rsUnused = statement.executeQuery( COUNT_UNUSED_PROV )) 
>   { countUnused = rsUnused.getInt( "no" ); }
>   if( countUnused != 0 )java.lang.System.out.printf( format, count, "unused" ); }
>
> private static void printUsed() 
> throws java.sql.SQLException
> { int countUsed = -1;
>   try( final java.sql.ResultSet rsUsed = statement.executeQuery( COUNT_USED_PROV )) 
>   { countUsed = rsUsed.getInt( "no" ); }
>   java.lang.System.out.printf( format, countUsed, "used" ); }
>
> private static void printAllStatistics() 
> throws java.sql.SQLException
> { printTotal();
>   printUnused();
>   printUsed(); }
>
> private static void makeFormatAndContinue()
> throws java.sql.SQLException
> { format = java.lang.String.format
>   ( "There are %%,%dd %%6s proverbs.%%n", java.lang.String.format( "%,d", count ).length() );
>   printAllStatistics(); }
>
> private static void makeCountAndContinue() 
> throws java.sql.SQLException
> { try( final java.sql.ResultSet rsTotal = statement.executeQuery( COUNT_TOTAL_PROV )) 
>   { count = rsTotal.getInt( "no" ); }
>   makeFormatAndContinue(); }
>
> private static void makeStatementAndContinue() 
> { try( final java.sql.Statement s = conn.createStatement() ) 
>   { statement = s; makeCountAndContinue(); }
>   catch( final java.sql.SQLException exception ) 
>   { java.lang.System.err.println( "Error in statistics" );
>     exception.printStackTrace();
>     fatalError( "" ); }}
>
> private static void printStatistics() 
> { makeStatementAndContinue(); }
>
> public static void main( final java.lang.String[] args ) 
> { java.lang.System.out.println( "OK" ); }}

Looks interesting, but personally I find it to complex.

-- 
Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof

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Thread

Is this the way to work with try with resources Cecil Westerhof <Cecil@decebal.nl> - 2017-08-08 13:26 +0200
  Re: Is this the way to work with try with resources Martin Gregorie <martin@address-in-sig.invalid> - 2017-08-08 12:51 +0000
    Re: Is this the way to work with try with resources Cecil Westerhof <Cecil@decebal.nl> - 2017-08-09 07:10 +0200
  Re: Is this the way to work with try with resources Patrick Roemer <sangamon@netcologne.de> - 2017-08-08 18:29 +0200
    Re: Is this the way to work with try with resources Cecil Westerhof <Cecil@decebal.nl> - 2017-08-09 07:20 +0200
    Re: Is this the way to work with try with resources Cecil Westerhof <Cecil@decebal.nl> - 2017-08-09 07:16 +0200
  Re: Is this the way to work with try with resources Patrick Roemer <sangamon@netcologne.de> - 2017-08-08 19:30 +0200
    Re: Is this the way to work with try with resources Cecil Westerhof <Cecil@decebal.nl> - 2017-08-09 06:49 +0200
    Re: Is this the way to work with try with resources Cecil Westerhof <Cecil@decebal.nl> - 2017-08-09 07:01 +0200
    Re: Is this the way to work with try with resources Patrick Roemer <sangamon@netcologne.de> - 2017-08-09 15:39 +0200
  Re: Is this the way to work with try with resources Arne Vajhøj <arne@vajhoej.dk> - 2017-08-08 21:25 -0400
    Re: Is this the way to work with try with resources Arne Vajhøj <arne@vajhoej.dk> - 2017-08-08 21:36 -0400
      Re: Is this the way to work with try with resources Cecil Westerhof <Cecil@decebal.nl> - 2017-08-09 07:29 +0200
        Re: Is this the way to work with try with resources Arne Vajhøj <arne@vajhoej.dk> - 2017-08-09 20:53 -0400
          Re: Is this the way to work with try with resources Arne Vajhøj <arne@vajhoej.dk> - 2017-08-09 23:03 -0400
    Re: Is this the way to work with try with resources Arne Vajhøj <arne@vajhoej.dk> - 2017-08-08 21:48 -0400
    Re: Is this the way to work with try with resources Cecil Westerhof <Cecil@decebal.nl> - 2017-08-09 07:24 +0200
  Re: Is this the way to work with try with resources Cecil Westerhof <Cecil@decebal.nl> - 2017-08-09 06:26 +0200
    Re: Is this the way to work with try with resources Cecil Westerhof <Cecil@decebal.nl> - 2017-08-09 08:30 +0200
    Re: Is this the way to work with try with resources Andreas Leitgeb <avl@logic.at> - 2017-08-09 09:40 +0000
      Re: Is this the way to work with try with resources Cecil Westerhof <Cecil@decebal.nl> - 2017-08-09 12:56 +0200
        Re: Is this the way to work with try with resources Andreas Leitgeb <avl@logic.at> - 2017-08-09 16:51 +0000
          Re: Is this the way to work with try with resources Cecil Westerhof <Cecil@decebal.nl> - 2017-08-09 19:37 +0200
            Re: Is this the way to work with try with resources Andreas Leitgeb <avl@logic.at> - 2017-08-09 19:51 +0000
              Re: Is this the way to work with try with resources Cecil Westerhof <Cecil@decebal.nl> - 2017-08-09 22:20 +0200
                Re: Is this the way to work with try with resources Cecil Westerhof <Cecil@decebal.nl> - 2017-08-09 23:17 +0200
          Re: Is this the way to work with try with resources Patrick Roemer <sangamon@netcologne.de> - 2017-08-09 22:08 +0200
        Re: Is this the way to work with try with resources Arne Vajhøj <arne@vajhoej.dk> - 2017-08-09 18:07 -0400
    Re: Is this the way to work with try with resources Arne Vajhøj <arne@vajhoej.dk> - 2017-08-09 18:05 -0400
  Re: Is this the way to work with try with resources Cecil Westerhof <Cecil@decebal.nl> - 2017-08-09 06:39 +0200

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