//=================================================================
//                   PostgreSQL_JDBC Class
//=================================================================
//
//    This class is used to control the running of the a generic
// class to access the PostgreSQL database.
//
//                  << PostgreSQL_JDBC.java >>
//
//=================================================================
// Copyright (C) 2010 Dana M. Proctor
// Version 1.02 10/21/2010
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version
// 2 of the License, or (at your option) any later version. This
// program is distributed in the hope that it will be useful, 
// but WITHOUT ANY WARRANTY; without even the implied warranty
// of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
// the GNU General Public License for more details. You should
// have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation,
// Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
// (http://opensource.org)
//
//-----------------------------------------------------------------
//                 danap@dandymadeproductions.com
//=================================================================

//=================================================================
//                PostgreSQL_JDBC Application
//=================================================================

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.io.*;
import java.sql.*;

/**
 * The PostgreSQL class is used to control the running of the a generic class to
 * access the PostgreSQL database. Arguments -debug.
 * @author Dana M. Proctor
 * @version 1.02 10/21/2010
 */

class PostgreSQL_JDBC
{
   //==============================================================
   // PostgreSQL_JDBC Constructor
   //==============================================================

   public PostgreSQL_JDBC(Connection con)
   {
      testColumnNull(con);
   }
   
   //==============================================================
   // Test Methods
   // CREATE DOMAIN salary_domain AS numeric(12,2) NOT NULL CHECK (value > 0);
   // CREATE TABLE employee (id integer not null, salary salary_domain);
   // DatabaseMetaData.getColumns(null, "public", "employee", "%"); 
   //==============================================================
   
   private void testColumnNull(Connection con)
   {
      // Method Instances
      DatabaseMetaData dbMetaData; 
      ResultSetMetaData tableMetaData;
      String sqlStatementString;
      Statement sqlStatement;
      ResultSet rs, db_resultSet;
      String identifierQuoteString = "\"";
      
      try
      {
         // Setup a connection statement.
         sqlStatement = con.createStatement();
         
         sqlStatementString = "SELECT * FROM " + identifierQuoteString + "public" + identifierQuoteString +
                              "." + identifierQuoteString + "employee" + identifierQuoteString +
         		               " LIMIT 1";
         System.out.println(sqlStatementString);

         db_resultSet = sqlStatement.executeQuery(sqlStatementString);
         dbMetaData = con.getMetaData();
         
         rs = dbMetaData.getColumns(null, "public", "employee", "%");
         
         while (rs.next())
         {
               System.out.print("Column Name: " + rs.getString("COLUMN_NAME") + " " 
                                + "IS_NULLABLE: " + rs.getString("IS_NULLABLE"));
               System.out.println();
         }
         
         rs.close();
         db_resultSet.close();
         sqlStatement.close();
      }
      catch (SQLException sqle)
      {
         System.out.println("SQL Exeception" + sqle);
      }
   }
   
   //============================================================
   // Main public access point method for instantiating the
   // PostgreSQL_JDBC application. Arguments: database, username,
   // & password.
   //==============================================================

   public static void main(String[] args)
   {
      String host, database, username, password;
      Connection dbConnection;

      // Collect connection properties. and setup connection.
      host = "localhost";
      dbConnection = null;

      if (args.length != 0)
      {
         database = args[0];
         username = (args.length > 1) ? args[1] : null;
         password = (args.length > 2) ? args[2] : null;
      }
      else
      {
         database = "your_database";
         username = "your_username";
         password = "your_password";
      }
      
      try
      {
         Class.forName("org.postgresql.Driver");
      }
      catch (ClassNotFoundException cne) {System.out.println("ClassNotFoundException"
                                          + cne.toString());}
      
      // Try to make a connection.
      try
      {
         dbConnection = DriverManager.getConnection("jdbc:postgresql://" + host + "/" + database,
                                                     username, password);
         // Connection Good.
         if (dbConnection != null)
         {
            System.out.println("Connection Created");
            
            // Go Do Something.
            new PostgreSQL_JDBC(dbConnection);
            
            // Close.
            dbConnection.close();
            System.out.println("Connection Closed");
         }
      }
      catch (SQLException sqle) {System.out.println("SQLExeception" + sqle.toString());}
   }
}