package org.ahmadsoft.stream.loader;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class CLTester {

	/**
	 * @param args
	 */
	public static void main(String[] args) throws Exception {
		runGC();
		long l1 = usedMemory();
		System.out.println("mem=" + (l1));

		Class.forName("com.mysql.jdbc.Driver");
		Connection connection = DriverManager
				.getConnection("jdbc:mysql://localhost/mysql?user=root&password=foo&defaultFetchSize=10&useCursorFetch=true");
		Statement stmt = connection.createStatement();
		stmt.setFetchDirection(ResultSet.FETCH_FORWARD);
		runGC();
		long l2 = usedMemory();
		System.out.println("mem=" + (l2));
		ResultSet rs = stmt.executeQuery("SELECT * FROM PRESIDENT");
		runGC();
		long l3 = usedMemory();
		System.out.println("mem=" + (l3));
		while (rs.next()) {
			//runGC();
			long l4 = usedMemory();
			System.out.println("  mem=" + (l4));
		}
		connection.close();
	}
    private static void runGC () throws Exception
    {
        // It helps to call Runtime.gc()
        // using several method calls:
        for (int r = 0; r < 4; ++ r) _runGC ();
    }
    private static void _runGC () throws Exception
    {
        long usedMem1 = usedMemory (), usedMem2 = Long.MAX_VALUE;
        for (int i = 0; (usedMem1 < usedMem2) && (i < 500); ++ i)
        {
            s_runtime.runFinalization ();
            s_runtime.gc ();
            Thread.currentThread ().yield ();
            
            usedMem2 = usedMem1;
            usedMem1 = usedMemory ();
        }
    }
    private static long usedMemory ()
    {
        return s_runtime.totalMemory () - s_runtime.freeMemory ();
    }
    
    private static final Runtime s_runtime = Runtime.getRuntime ();
}