DatabaseConnection.java

package arcade.database;

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.logging.FileHandler;
import java.util.logging.Logger;


/**
 * Establishes connection to the database
 * @author Natalia Carvalho
 * @editor Joshua Waldman
 */
public class DatabaseConnection {

    private static final String URL = "jdbc:postgresql://cgi.cs.duke.edu/nrc10";
    private static final String USER = "nrc10";
    private static final String PASSWORD = "aUsg5xj2f";
    private Connection myConnection;
    private PreparedStatement myPreparedStatement; 
    private ResultSet myResultSet;
    private FileHandler myDatabaseErrorLog;
    private Logger myLogger;


    /**
     * Constructor for DatabaseConnection that establishes connection to database
     */
    public DatabaseConnection() {
        establishConnectionToDatabase();
        try {
            myDatabaseErrorLog = new FileHandler(System.getProperty("user.dir") + 
                    "/src/arcade/resources/logs/ErrorLog.log");
            myLogger = Logger.getLogger(Table.class.getName());
            myLogger.addHandler(myDatabaseErrorLog);
        }
        catch (IOException e) {
            System.err.println("File not found");
        } 
    }
    
    private void establishConnectionToDatabase() {
        try {
            Class.forName("org.postgresql.Driver");
        }
        catch (ClassNotFoundException e) {
            logError("Class not found for Database in DatabaseConnection.java");
        }

        myConnection = null;
        try {
            myConnection = DriverManager.getConnection(URL, USER, PASSWORD);
        }
        catch (SQLException e) {
            logError("SQL Error connection to database in DatabaseConnection.java");
        }
        myResultSet = null;
        myPreparedStatement = null;
    }
    
    /**
     * Closes Connection, ResultSet, and PreparedStatements once done with database
     */
    public void closeConnection() {
        try {
            if (myPreparedStatement != null) {
                myPreparedStatement.close();
            }
            if (myResultSet != null) {
                myResultSet.close();
            }
            if (myConnection != null) {
                myConnection.close();
            }
        }
        catch (SQLException e) {
            logError("Error closing connection in DatabaseConnection.java");
        }
    }
       
    /**
     * Returns established connection
     */
    public Connection getConnection() {
        return myConnection;
    }
    
    /**
     * Returns established ResultSet
     */
    public ResultSet getResultSet() {
        return myResultSet;
    }
    
    /**
     * Returns established prepared statement
     */
    public PreparedStatement getPreparedStatement() {
        return myPreparedStatement;
    }
    /**
     * Logs an error in the logger file
     * @param errorToBeLogged is error that's logged
     */
    public void logError(String errorToBeLogged) {
        myLogger.info(errorToBeLogged);
    }

}