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From: Cecil Westerhof <Cecil@decebal.nl>
Newsgroups: comp.lang.java.programmer
Subject: Is this the way to work with try with resources
Date: Tue, 08 Aug 2017 13:26:44 +0200
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When using with resources you ‘should’ always work with try with
resources. At the moment I have something like the following code:
    private static void statistics() {
        try (Statement stmt = conn.createStatement()) {
            String format;

            try (ResultSet rsTotal = stmt.executeQuery(COUNT_TOTAL_PROV)) {
                final int count = rsTotal.getInt("no");

                format = String.format("There are %%,%dd %%6s proverbs.%%n", String.format("%,d", count).length());
                System.out.printf(format, count, "total");
            }
            try (ResultSet rsUnused = stmt.executeQuery(COUNT_UNUSED_PROV)) {
                final int count = rsUnused.getInt("no");

                if (count != 0) {
                    System.out.printf(format, count, "unused");
                }
            }
            try (ResultSet rsUsed = stmt.executeQuery(COUNT_USED_PROV)) {
                final int count = rsUsed.getInt("no");

                System.out.printf(format, count, "used");
            }
        } catch (SQLException e) {
            System.err.printf("Error in statistics\n");
            e.printStackTrace();
            fatalError("");
        }
    }

It feels a bit long-winded. Is this the way to go, or is there a
better way?


I thought that I could rewrite it to:
    private static void statistics() {
        try (Statement stmt     = conn.createStatement();
             ResultSet rsTotal  = stmt.executeQuery(COUNT_TOTAL_PROV);
             ResultSet rsUnused = stmt.executeQuery(COUNT_UNUSED_PROV);
             ResultSet rsUsed   = stmt.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("");
        }
    }

That would be a little better I think, but when there are a lot of
queries to be done, you need to define a lot of extra result-sets.

But there is a problem with that. If I do that, all three result-sets
have the same query: the last one.
What is the reason for this? I am using SQLite3.

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