/*
 * This file defines an object which retrieves data
 * from a database table cars(name,image)
 * where name is a string and image is a blob.
 *
 * The getCarList method retrieves a list of the
 * names of all cars in the database.
 *
 * The getImage method retrieves a picture of a
 * car, given the car's name, as an
 * input stream.
 */

// You need to import the java.sql package to use JDBC
import oracle.sql.*;
import oracle.jdbc.driver.*;
import java.sql.*;
import java.io.*;
import java.util.*;

class DatabaseAccess {

    Connection conn;

    DatabaseAccess()
    {
      try {
	  // Load the Oracle JDBC driver
	  DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());

	  // Connect to the database
	  // You can put a database name after the @ sign in the connection URL.
	  conn =
	    DriverManager.getConnection ("jdbc:oracle:thin:@occs.cs.oberlin.edu:1521:occs", "alice", "tiger");
	  conn.setAutoCommit(false);
      }
      catch (SQLException e){
        System.out.println(e);
        System.exit(1);
      }
    }

    public List<String> getCarList() {
        List<String> result = new ArrayList<String>();
        try {
           Statement stmt = conn.createStatement();
           ResultSet rset = stmt.executeQuery("select name from cars order by name");
           while(rset.next())
              result.add(rset.getString(1));
        }
        catch(SQLException e){
           System.out.println(e);
           return result;
        }
        return result;
    }

    public InputStream getImageStream(String name) {
       InputStream stream = null;
       try {
          Statement stmt = conn.createStatement();
          ResultSet rset = stmt.executeQuery("select image from cars "+
             "where name = '" + name + "'");
          if(rset.next()){
             BLOB blob = ((OracleResultSet)rset).getBLOB(1);
             if(blob!=null)
                stream = blob.getBinaryStream();
          }
       }
       catch (SQLException e){
          throw new RuntimeException(e.getMessage());
       }
       return stream==null?null:stream;
    }
            
}