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From: Cecil Westerhof <Cecil@decebal.nl>
Newsgroups: comp.lang.java.programmer
Subject: Re: Is this the way to work with try with resources
Date: Wed, 09 Aug 2017 08:30:51 +0200
Organization: Decebal Computing
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Cecil Westerhof <Cecil@decebal.nl> writes:

> The solution is to have a statement pro result-set, but than this
> statement is only necessary for getting the result-set. So I rewrote
> statistics to:
>     private static void statistics() {
>         try (ResultSet rsTotal  = executeQuery(COUNT_TOTAL_PROV);
>              ResultSet rsUnused = executeQuery(COUNT_UNUSED_PROV);
>              ResultSet rsUsed   = executeQuery(COUNT_USED_PROV)) {
>             int    count;
>             String format;
>
>             count  = rsTotal.getInt("no");
>             format = String.format("There are %%,%dd %%-6s proverbs.%%n",
>                                    String.format("%,d", count).length());
>             System.out.printf(format, count, "total");
>             count  = rsUnused.getInt("no");
>             if (count != 0) {
>                 System.out.printf(format, count, "unused");
>             }
>             count  = rsUsed.getInt("no");
>             System.out.printf(format, count, "used");
>         } catch (SQLException e) {
>             System.err.printf("Error in statistics\n");
>             e.printStackTrace();
>             fatalError("");
>         }
>     }
>
> And wrote the function executeQuery to make the code a little more
> compact:
>     private static ResultSet executeQuery(String query) throws SQLException {
>         return conn.createStatement().executeQuery(query);
>     }

This is a very simple case: I only retrieve a count. So I rewrote it
to:
    private static void statistics() {
        try  {
            int    count;
            String format;

            count  = getCount(COUNT_TOTAL_PROV);
            format = String.format("There are %%,%dd %%-6s proverbs.%%n",
                                   String.format("%,d", count).length());
            System.out.printf(format, count, "total");
            count  = getCount(COUNT_UNUSED_PROV);
            if (count != 0) {
                System.out.printf(format, count, "unused");
            }
            count  = getCount(COUNT_USED_PROV);
            System.out.printf(format, count, "used");
        } catch (SQLException e) {
            System.err.printf("Error in statistics%n");
            e.printStackTrace();
            fatalError("");
        }
    }

And I defined a function getCount:
    private static int getCount(String query) throws SQLException {
        int count;

        try (ResultSet rsCount  = executeQuery(query)) {
            count = rsCount.getInt("count");
        }
        return count;
    }

So in this case there are not multiple ResultSet and implicit
Statement.

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