// Review: Packages Not Specified
///Classes


    //Change this class method if your database changes
class ConnectionGenerator
    public static Connection generateConnection()
        Create Connection sqliteConnection
        Load JDBC Driver ex: "org.sqlite.JDBC"
        set sqliteConnection by calling DriverManager.getConnection('Connection URL')
        return sqliteConnection


    //User class for User object
public class User
    //MEMBER VARIABLES
    private String mstrUsername;
    private String mstrPassword;

    //CONSTRUCTOR
    public User(String lUsername, String lPassword)
        set mstrUsername <- lUsername
        set mstrPassword <- lPassword

    //GETTER METHODS
    public String getMstrUsername()
        return mstrUsername;

    public String getMstrPassword()
        return mstrPassword;


public class Customer
    private int miCustomerID;
    private String mstrCustomerName;
    private String mstrCustomerType;
    private boolean mbIsActive;
    private double mdCreditLimit;

    //CONSTRUCTOR
    public Customer(int pCustomerID, String pName, String pType, boolean pIsActive, double pCreditLimit)
        miCustomerID <- pCustomerID
        mstrCustomerName <- pName
        mstrCustomerType <- pType
        mbIsActive <- pIsActive
        mdCreditLimit <- pCreditLimit

    // Public GETTERS FOR ALL MEMBERS
    public int getMiCustomerID()
        return miCustomerID
    public String getMstrCustomerName()
        return mstrCustomerName
    public String getMstrCustomerType()
        return mstrCustomerType
    public boolean getMbIsActive()
        return mbIsActive
    public double getMdCreditLimit()
        return mdCreditLimit



public class Invoice
    //MEMBER VARIABLES
    private String mstrCustomerName;
    private int miInvoiceID;
    private double mdInvoiceAmount;
    private Date mInvoiceDate;
    private int miStatus;
    private int miCustomerID;
    private Date mPaidDate;
    private Date mDueDate;

    //CONSTRUCTOR
    public Invoice(String pCustomerName, int pInvoiceID, double pInvoiceAmount, Date pInvoiceDate, int pStatus, int pCustomerID, Date pPaidDate, Date pDueDate)
        mstrCustomerName <- pCustomerName
        miInvoiceID <- pInvoiceID
        mdInvoiceAmount <- pInvoiceAmount
        mInvoiceDate <- pInvoiceDate
        miStatus <- pStatus
        miCustomerID <- pCustomerID
        mPaidDate <- pPaidDate
        mDueDate <- pDueDate


    public String getMstrCustomerName()
        return mstrCustomerName

    public int getMiInvoiceId()
        return miInvoiceID

    public double getMdInvoiceAmount()
        return mdInvoiceAmount

    public Date mInvoiceDate()
        return mInvoiceDate

    public int getMiStatus()
        return miStatus

    public int getMiCustomerID()
        return miCustomerID

    public Date getMPaidDate()
        return mPaidDate

    public Date getMDueDate()
        return mDueDate





///DAO INTERFACES :
public interface LoginDAO
    public boolean doLogin(User pUser);


public interface CustomerDAO
    public boolean putCustomer(Customer pCustomer);
    public ArrayList<Customer> getAllCustomerList();
    public Customer getCustomer(int pCustomerID);


public interface InvoiceDAO
    public Invoice getInvoice(int pInvoiceID);
    public ArrayList<Invoice> getAllInvoiceList();
    public ArrayList<Invoice> getCustomerInvoiceList(int pCustomerID);





///DAO IMPLEMENTATIONS:
public class MyLoginDAO implements LoginDAO
    public boolean doLogin(User pUser)
        Create Connection loginConnection <- ConnectionGenerator.generateConnection()
        Create a prepared Statement lLoginStatement ("select * from users where username=? and password=?")
        Set String 1 by pUser.getMstrUsername()
        Set . 2 by pUser.getMstrPassword()
        ResultSet lLoginResult <- executeQuery preparedStatement
        if (lLoginResult.next())
            return true
        else
            return false


public class MyCustomerDAO implements CustomerDAO
    public boolean putCustomer(Customer pCustomer)
        Create Connection putterConnection <- ConnectionGenerator.generateConnection()
        Create a prepared Statement putterStatement (insert into customers values(?,?,?,?,?))
        Set int 1 by pCustomer.getMiCustomerID()
        Set String 2 by pCustomer.getMstrCustomerName()
        Set String 3 by pCustomer.getMstrCustomerType()
        Set boolean 4 by pCustomer.getMbIsActive()
        Set double 5 by pCustomer.getMdCreditLimit()
        int liRowsAffected = putterStatement . executeUpdate()
        if(liRowsAffected == 1)
            return true
        else
            return false

    public boolean updateCustomer(Customer pCustomer)
        Create Connection putterConnection <- ConnectionGenerator.generateConnection()
        Create a prepared Statement putterStatement (update customers set customerName=?, customerType=?, isActive=?, creditLimit=? where customerID=?)

        Set String 1 by pCustomer.getMstrCustomerName()
        Set String 2 by pCustomer.getMstrCustomerType()
        Set boolean 3 by pCustomer.getMbIsActive()
        Set double 4 by pCustomer.getMdCreditLimit()
        set int 5 by pCustomer.getMiCustomerID
        int liRowsAffected = putterStatement . executeUpdate()
        if(liRowsAffected == 1)
            return true
        else
            return false


    public ArrayList<Customer> getAllCustomerList()
        ArrayList<Customer> lCustomerList
        Create Connection getAllCustomerConnection <- ConnectionGenerator.generateConnection()
        Create a preparedStatement getAllCustomerStatement (select * from customers)
        ResultSet customerSet = executeQuery
        while (customer.next())
            lCustomerList.add(new Customer(getInt(1), getString(2), getString(3), getBoolean(4), getDouble(5)))
        return lCustomerList

    public Customer getCustomer(int pCustomerID)
        Create customerGetConnection <- ConnectionGenerator.generateConnection()
        Create preparedStatement customerGetStatement (select * from customers where customerID=?)
        set int 1 as pCustomerID
        ResultSet customerResult <- executeQuery
        if(customerResult.next())
            return new Customer(getInt(1), getString(2), getString(3), getBoolean(4), getDouble(5))
        else
            return null



public class MyInvoiceDAO implements InvoiceDAO
    // METHOD TO GET INVOICE OBJECT FROM InvoiceID
    public Invoice getInvoice(int pInvoiceID)
        Create invoiceGetConnection <- ConnectionGenerator.generateConnection()
        Create preparedStatement invoiceGetStatement (select * from invoices where invoiceID=?)
        set int 1 as pInvoiceID
        ResultSet invoiceResult <- executeQuery
        if(invoiceResult.next())
            return new Invoice(getString(1), getInt(2), getDouble(3), getDate(4), getInt(5), getInt(6), getDate(7), getDate(8))
        else
            return null

    //METHOD TO GET ALL LIST OF ALL INVOICES FROM ALL USERS
    public ArrayList<Invoice> getAllInvoiceList()
        ArrayList<Invoice> lInvoiceList
        Create Connection getAllInvoicesConnection <- ConnectionGenerator.generateConnection()
        Create a preparedStatement getAllInvoicesStatement(select * from invoices)
        ResultSet invoiceSet = getAllInvoicesStatement.executeQuery()
        while (invoiceSet.next())
            lInvoiceList.add( new Invoice(getString(1), getInt(2), getDouble(3), getDate(4), getInt(5), getInt(6), getDate(7), getDate(8)))
        return lInvoiceList


    //METHOD TO GET LIST OF ALL INVOICES FROM A PARTICULAR CUSTOMER
    public ArrayList<Invoice> getCustomerInvoiceList(int pCustomerID);
        ArrayList<Invoice> lInvoiceList = new ArrayList<Invoice>();
        Create Connection getCustomerInvoiceConnection <- ConnectionGenerator.generateConnection()
        Create a preparedStatement getCustomerInvoiceStatement(select * from invoices where customerID=?)
        getCustomerInvoiceConnection.setInt()
        ResultSet invoiceSet = getAllInvoicesStatement.executeQuery()
        while (invoiceSet.next())
            lInvoiceList.add( new Invoice(getString(1), getInt(2), getDouble(3), getDate(4), getInt(5), getInt(6), getDate(7), getDate(8)))
        return lInvoiceList


    public boolean updateInvoice(Invoice pInvoice)
        Create Connection updateConnection <- ConnectionGenerator.generateConnection()
        Create a prepared Statement updaterStatement (update invoices set status=?, paidDate=?, dueDate=? where invoiceID=?)
        set Boolean 1 as getStatus
        set Date 2 as getpaidDate
        set Date 3 as getDueDate
        set int 4 as invoiceID
        int liRowsAffected = putterStatement . executeUpdate()
        if(liRowsAffected == 1)
            return true
        else
            return false



    public boolean putInvoice(Invoice pInvoice)
        Create Connection updateConnection <- ConnectionGenerator.generateConnection()
        Create a prepared Statement updaterStatement (insert into invoices values(?,?,?,?,?,?,?,?))
        set 1 as getMstrCustomerName
        set 2 as miInvoiceID
        set 3 as mdInvoiceAmount
        set 4 as mInvoiceDate
        set 5 as miStatus
        set 6 as miCustomerID
        set 7 as mPaidDate
        set 8 as mDueDate
        int liRowsAffected = putterStatement . executeUpdate()
        if(liRowsAffected == 1)
            return true
        else
            return false



/// BASE SERVLET CLASS FOR VALIDATION IN ALL SERVLETS
public class MyHttpServlet extends HttpServlet
    protected void service(HttpServletRequest request, HttpServletResponse response)
        if(request.getSession.getAttribute("activeUser") is null)
            redirect to PreLogin servlet
        else
            super.service(request,response)


/// PRELOGIN SERVLET
public class PreLogin extends HttpServlet
    protected void service(HttpServletRequest request, HttpServletResponse response)
        if(request.getSession.getAttribute("activeUser") not null)
            redirect to AdminPanel servlet
        else
            super.service(request,response)

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
        forward request to login.jsp


/// SUBMITLOGIN Servlet accessed after login.jsp
public class SubmitLogin extends HttpServlet
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
        Get username and password from request objects.
        Create a User object and getLoginDAOInstance() from DAO Factory
        if(ldaoInstance.doLogin() is true)
            request.getSession().setAttribute "activeUser" with User object
            redirect to AdminPanel servlet
        else
            print fail on response object

/// AdminPanel Servlet forwads to admin-panel.jsp
public class AdminPanel extends MyHttpServlet
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
        forward request to admin-panel.jsp

/// CustomerListServlet forwards to customer-list-maker.jsp
public class CustomerListServlet extends MyHttpServlet
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
        get customerDAOInstance from DAO Factory
        and retrieve Arraylist of Customer...
        Set the arraylist as request Attribute
        forward request to cutomer-list-maker.jsp

/// AddUpdateCustomer can add or update customer details
public class AddUpdateCustomer extends MyHttpServlet
    //DOPOST TO HANDLE Add / Update request
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
        check if request parameter customerID set
            call editMode(request,response)
        else
            call newMode(request,response)


    private void editMode(HttpServletRequest request, HttpServletResponse response)
        get request parameter CustomerID
        Create CustomerDAO object customerdao by getCustomerDAOInstance()
        Get Customer object by - customerdao.getCustomer(customerID)
        set the cutomer object as Attribute in request
        forward the request to cutomer-form-maker.jsp

    private void newMode(HttpServletRequest request, HttpServletResponse response)
        Generate a random int CustomerID
        Create Customer object by using CustomerID as newly generated int and rest of the fields empty
        set the cutomer object as Attribute in request
        forward the request to cutomer-form-maker.jsp



/// Submits the customer details to commit to database
// Review : servlet Name?
public class SubmitCustomerForm extends MyHttpServlet
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
        get mstrCustomerID mstrCustomerName mstrCustomerType mbIsActive mdCreditLimit from getParameter()
        Create a new Customer Object
        customerdao getCustomerDAOInstance from DAO Factory
        if parameter mode = new
            Write into response, result of === >   customerdao.putCustomer(customer object)
        else
            Write into response, result of === >   customerdao.updateCustomer(Customer object)


/// InvoiceList servlet forwards the request to invoice-list-maker.jsp
public class InvoiceList extends MyHttpServlet
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
        create InvoiceDAO object - invoicedao from Daofactory
        call the invoicedao.getAllInvoiceList() and store it in ArrayList<Invoice>
        set the request attribute to ArrayList<Invoice>
        forward request to invoice-list-maker.jsp


/// InvoicePanel forwards the request to invoice-manager.jsp
public class InvoicePanel extends MyHttpServlet
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
        forward request to invoice-manager.jsp


/// AddUpdateInvoice displays invoice form in add or edit mode
public class AddUpdateInvoice extends MyHttpServlet
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
        check if request parameter invoiceID set
            call editMode(request,response)
        else
            call newMode(request,response)


    private void editMode(HttpServletRequest request, HttpServletResponse response)
        get request parameter invoiceID
        Create InvoiceDAO object invoicedao by getInvoiceDAOInstance()
        Get Invoice object by - invoice.getInvoice(invoiceID)
        set the invoice object as Attribute in request
        forward the request to invoice-form-maker.jsp

    private void newMode(HttpServletRequest request, HttpServletResponse response)
        Generate a random int invoiceID
        Create Invoice object by using invoiceID as newly generated int and rest of the fields empty
        set the invoice object as Attribute in request
        forward the request to invoice-form-maker.jsp


/// COMMIT THE CHANGES IN INVOICES TO THE DATABASE
public class SubmitInvoice extends MyHttpServlet
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
        get mstrCustomerName miInvoiceID mdInvoiceAmount mInvoiceDate miStatus miCustomerID mPaidDate mDueDate from getParameter()
        Create a new Invoice Object
        invoicedao getInvoiceDAOInstance from DAO Factory
        if parameter mode = new
            Write into response, result of === >   invoicedao.putInvoice(invoice object)
        else
            Write into response, result of === >   invoice.updateInvoice(invoice object)




///JSPs
//login.jsp
        login form submit takes you to SubmitLogin and on success it redirects to AdminServlet which forwards to admin-panel.jsp
        if failed on SubmitLogin ...... we go back to login.jsp


//admin-panel.jsp
        Add Customer button - calls the AddUpdateCustomer Servlet with mode=new and shows the output customer-form-maker.jsp in bottom div

        View customer list calls the CustomerManager servlet which prints the customer list table which is customer-list-maker.jsp in bottom div

        View Invoice List button - calls the InvoiceList which prints the invoice list table which is invoice-list-maker.jsp in bottom div

//invoice-panel.jsp
        AddInvoiceButton: calls the AddUpdateInvoice Servlet with mode=new and show output invoice-form-maker.jsp in bottom div

        View Invoice List calls InvoiceManager servlet which prints the output of invoice-list-maker.jsp in bottom div


// customer-list-maker.jsp
        Prints the list of customers..
            Takes the ArrayList<Customer> from the request Attribute
            print the table of Customers one by one
                1. Clicking on customer name will open customer-form-maker.jsp in edit mode
                2. Clicking on Add invoice against ever customer will open invoice-form-maker.jsp in new mode

// customer-form-maker
        Take the Customer object from the request
        Print the customer form in edit/new mode
        submit will call the SubmitCustomerForm servlet

// invoice-list-maker
        Take the ArrayList<Invoice> attribute from the request
        print the table of Invoice one by one
            1. Clicking on Checkbox for unpaid invoices and submit will call InvoiceManager and update the invoices
            2. Clicking on individual invoice IDs will open invoice-form-maker in edit mode

// invoice-form-maker
        Take the Invoice object from the request
        Print the Invoice form in edit/new mode
        submit will call the SubmitInvoice Servlet and send the form