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@@ -0,0 +1,109 @@
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+package hello;
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+
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+import java.io.*;
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+import java.sql.*;
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+import java.util.*;
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+import java.util.concurrent.*;
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+
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+import javax.annotation.*;
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+import javax.servlet.*;
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+import javax.servlet.http.*;
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+import javax.sql.*;
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+
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+/**
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+ * Database connectivity (with a Servlet-container managed pool) test.
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+ */
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+@SuppressWarnings("serial")
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+public class PostgresUpdateServlet extends HttpServlet
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+{
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+ // Database details.
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+ private static final String DB_QUERY = "SELECT * FROM World WHERE id = ?";
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+ private static final String UPDATE_QUERY = "UPDATE World SET randomNumber = ? WHERE id = ?";
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+ private static final int DB_ROWS = 10000;
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+
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+ // Database connection pool.
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+ @Resource(name="jdbc/postgres_hello_world")
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+ private DataSource postgresDataSource;
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+
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+ @Override
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+ protected void doGet(HttpServletRequest req, HttpServletResponse res)
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+ throws ServletException, IOException
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+ {
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+ // Set content type to JSON
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+ res.setHeader(Common.HEADER_CONTENT_TYPE, Common.CONTENT_TYPE_JSON);
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+
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+ // Reference the data source.
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+ final DataSource source = postgresDataSource;
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+
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+ // Get the count of queries to run.
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+ int count = 1;
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+ try
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+ {
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+ count = Integer.parseInt(req.getParameter("queries"));
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+
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+ // Bounds check.
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+ if (count > 500)
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+ {
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+ count = 500;
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+ }
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+ if (count < 1)
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+ {
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+ count = 1;
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+ }
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+ }
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+ catch (NumberFormatException nfexc)
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+ {
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+ // Do nothing.
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+ }
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+
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+ // Fetch some rows from the database.
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+ final World[] worlds = new World[count];
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+ final Random random = ThreadLocalRandom.current();
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+
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+ try (Connection conn = source.getConnection())
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+ {
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+ try (PreparedStatement statement = conn.prepareStatement(DB_QUERY,
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+ ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY))
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+ {
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+ // Run the query the number of times requested.
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+ for (int i = 0; i < count; i++)
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+ {
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+ final int id = random.nextInt(DB_ROWS) + 1;
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+ statement.setInt(1, id);
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+
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+ try (ResultSet results = statement.executeQuery())
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+ {
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+ if (results.next())
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+ {
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+ worlds[i] = new World(id, results.getInt("randomNumber"));
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+
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+ // Update row
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+ try (PreparedStatement statement2 = conn.prepareStatement(UPDATE_QUERY))
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+ {
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+ worlds[i].setRandomNumber(random.nextInt(DB_ROWS) + 1);
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+ statement2.setInt(1, worlds[i].getRandomNumber());
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+ statement2.setInt(2, id);
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+
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+ statement2.execute();
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+ }
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+ }
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+ }
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+ }
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+ }
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+ }
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+ catch (SQLException sqlex)
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+ {
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+ System.err.println("SQL Exception: " + sqlex);
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+ }
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+
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+ // Write JSON encoded message to the response.
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+ try
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+ {
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+ Common.MAPPER.writeValue(res.getOutputStream(), worlds);
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+ }
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+ catch (IOException ioe)
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+ {
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+ // do nothing
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+ }
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+ }
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+}
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