PROGRAM 1


//  Filename:  Post1.java, Post2.java     Author:  Anthony F. Ortiz
//  Since there are security restrictions for these two applets, I
//  included equivalent application versions, Post3.java, Post4.java.
//  However, both appletviewer and Netscape 3.0 will work for these
//  applets.

//  Filename:  Post3.java     Author:  Anthony F. Ortiz
//  This is the main version 1 of the post application.  It focuses on
//  materialization and dematerialization of a ProductSpecification.

import java.awt.*;

public class Post3 extends Frame
{
    private ProductSpecificationProxy psProxy;
    private BrokerServer bServer = BrokerServer.getInstance ();
    private Label postLabel, oidLabel, descriptionLabel, priceLabel, upcLabel, objectLabel;
    private TextField oidText, descriptionText, priceText, upcText;
    private Button changeButton, commitButton, displayButton, insertButton, removeButton, rollbackButton;

    //  draws the interface.
    public static void main (String [] args)
    {
        Frame p = new Post3 ();
        p.resize (640, 480);
        p.setTitle ("Post3");
        p.show ();
    }

    public Post3 ()
    {
        int height = 480 / 9;
        //  CSU-Hayward colors
        setBackground (Color.red);
        setForeground (Color.black);
        Font font = new Font ("Courier", Font.BOLD, 12);
        setFont (font);
        setLayout (null);

        postLabel = new Label ("Post");
        postLabel.reshape (10, 1 * height, 250, 25);
        add (postLabel);

        oidLabel = new Label ("Enter an psOID:");
        oidLabel.reshape (10, 2 * height, 200, 25);
        add (oidLabel);

        oidText = new TextField ();
        oidText.reshape (220, 2 * height, 200, 25);
        add (oidText);

        descriptionLabel = new Label ("Enter a description:");
        descriptionLabel.reshape (10, 3 * height, 200, 25);
        add (descriptionLabel);

        descriptionText = new TextField ();
        descriptionText.reshape (220, 3 * height, 200, 25);
        add (descriptionText);

        priceLabel = new Label ("Enter a price:");
        priceLabel.reshape (10, 4 * height, 200, 25);
        add (priceLabel);

        priceText = new TextField ();
        priceText.reshape (220, 4 * height, 200, 25);
        add (priceText);

        upcLabel = new Label ("Enter a UPC:");
        upcLabel.reshape (10, 5 * height, 200, 25);
        add (upcLabel);

        upcText = new TextField ();
        upcText.reshape (220, 5 * height, 200, 25);
        add (upcText);

        changeButton = new Button ("Change");
        changeButton.reshape (430, 2 * height, 200, 25);
        add (changeButton);

        insertButton = new Button ("Insert");
        insertButton.reshape (430, 3 * height, 200, 25);
        add (insertButton);

        removeButton = new Button ("Remove");
        removeButton.reshape (430, 4 * height, 200, 25);
        add (removeButton);

        displayButton = new Button ("Display");
        displayButton.reshape (430, 5 * height, 200, 25);
        add (displayButton);

        commitButton = new Button ("Commit");
        commitButton.reshape (220, 6 * height, 200, 25);
        add (commitButton);

        rollbackButton = new Button ("Rollback");
        rollbackButton.reshape (430, 6 * height, 200, 25);
        add (rollbackButton);

        objectLabel = new Label ("PS Record!");
        objectLabel.reshape (220, 7 * height, 200, 25);
        add (objectLabel);
    }

    //  Close window.
    public boolean handleEvent (Event event)
    {
        if (event.id == Event.WINDOW_DESTROY)
        {
            System.exit (0);
        }
        return (super.handleEvent (event));
    }

    //  These are the actions taken by the different buttons.  The
    //  actions include, change ps, commit changes, display ps, insert ps,
    //  remove ps, and rollback changes.
    public boolean action (Event event, Object object)
    {
        if (event.target == changeButton)
        {
            psProxy = new ProductSpecificationProxy (oidText.getText ());
            objectLabel.setText ("Change ps: " + descriptionText.getText () + " " + priceText.getText () + " " + upcText.getText ());
            if (descriptionText.getText () != "")
            {
                psProxy.setDescription (descriptionText.getText ());
            }
            if (priceText.getText () != "")
            {
                psProxy.setPrice ((float) new Double (priceText.getText ()).doubleValue ());
            }
            if (upcText.getText () != "")
            {
                psProxy.setUPC (Integer.parseInt (upcText.getText ()));
            }
            return true;
        }
        else if (event.target == commitButton)
        {
            objectLabel.setText ("Commit:");
            oidText.setText ("");
            descriptionText.setText ("");
            priceText.setText ("");
            upcText.setText ("");
            bServer.commit ();
            return true;
        }
        else if (event.target == displayButton)
        {
            psProxy = new ProductSpecificationProxy (oidText.getText ());
            descriptionText.setText (psProxy.getDescription ());
            priceText.setText ("" + psProxy.getPrice ());
            upcText.setText ("" + psProxy.getUPC ());
            objectLabel.setText ("Display ps: " + descriptionText.getText () + " " + priceText.getText () + " " + upcText.getText ());
            return true;
        }
        else if (event.target == insertButton)
        {
            String anOID = RandomNumberGenerator.getRandomNumber ();
            psProxy = new ProductSpecificationProxy (anOID, Integer.parseInt (upcText.getText ()), (float) new Double (priceText.getText ()).doubleValue (), descriptionText.getText ());
            objectLabel.setText ("Insert ps: " + descriptionText.getText () + " " + priceText.getText () + " " + upcText.getText ());
            oidText.setText (anOID);
            return true;
        }
        else if (event.target == removeButton)
        {
            psProxy = new ProductSpecificationProxy (oidText.getText ());
            psProxy.remove ();
            descriptionText.setText (psProxy.getDescription ());
            priceText.setText ("" + psProxy.getPrice ());
            upcText.setText ("" + psProxy.getUPC ());
            objectLabel.setText ("Remove ps: " + descriptionText.getText () + " " + priceText.getText () + " " + upcText.getText ());
            return true;
        }
        else if (event.target == rollbackButton)
        {
            objectLabel.setText ("Rollback: ");
            oidText.setText ("");
            descriptionText.setText ("");
            priceText.setText ("");
            upcText.setText ("");
            bServer.rollback ();
            psProxy.reset ();
            return true;
        }
        else
        {
            return false;
        }
    }
}

//  Filename:  Post4.java     Author:  Anthony F. Ortiz
//  This is the main version 2 of the post application.  It focuses on
//  materialization of a ProductSpecification, SaleLineItem, and Sale.

import java.applet.Applet;
import java.awt.*;

public class Post4 extends Frame
{
    private ProductSpecificationProxy psProxy;
    private SaleLineItemProxy sliProxy;
    private SaleProxy sProxy;
    private Label psLabel, sliLabel, sLabel, resultsLabel, postLabel;
    private TextField psText, sliText, sText;
    private Button psButton, sliButton, sButton;

    //  draws the interface.
    public static void main (String [] args)
    {
        Frame p = new Post4 ();
        p.resize (640, 480);
        p.setTitle ("Post4");
        p.show ();
    }

    public Post4 ()
    {
        int height = 480 / 7;
        //  CSU-Hayward colors
        setBackground (Color.red);
        setForeground (Color.black);
        Font font = new Font ("Courier", Font.BOLD, 12);
        setFont (font);
        setLayout (null);

        postLabel = new Label ("Post");
        postLabel.reshape (10, 1 * height, 250, 25);
        add (postLabel);

        psLabel = new Label ("Enter an psOID:");
        psLabel.reshape (10, 2 * height, 200, 25);
        add (psLabel);

        psText = new TextField ();
        psText.reshape (220, 2 * height, 200, 25);
        add (psText);

        psButton = new Button ("Display ProductSpecification");
        psButton.reshape (430, 2 * height, 200, 25);
        add (psButton);

        sliLabel = new Label ("Enter an sliOID:");
        sliLabel.reshape (10, 3 * height, 200, 25);
        add (sliLabel);

        sliText = new TextField ();
        sliText.reshape (220, 3 * height, 200, 25);
        add (sliText);

        sliButton = new Button ("Display SaleLineItem");
        sliButton.reshape (430, 3 * height, 200, 25);
        add (sliButton);

        sLabel = new Label ("Enter an sOID:");
        sLabel.reshape (10, 4 * height, 200, 25);
        add (sLabel);

        sText = new TextField ();
        sText.reshape (220, 4 * height, 200, 25);
        add (sText);

        sButton = new Button ("Display Sale");
        sButton.reshape (430, 4 * height, 200, 25);
        add (sButton);

        resultsLabel = new Label ("Results go here!");
        resultsLabel.reshape (220, 5 * height, 400, 25);
        add (resultsLabel);

    }

    //  Close window.
    public boolean handleEvent (Event event)
    {
        if (event.id == Event.WINDOW_DESTROY)
        {
            System.exit (0);
        }
        return (super.handleEvent (event));
    }

    //  These are the actions taken by the different buttons.  The
    //  actions include, display ProductSpecification (description, price,
    //  and upc), display SaleLineItem (total of a SaleLineItem), and
    //  display Sale (total of one or more SaleLineItems).
    public boolean action (Event event, Object object)
    {
        if (event.target == psButton)
        {
            psProxy = new ProductSpecificationProxy (psText.getText ());
            resultsLabel.setText (psProxy.getDescription () + " " + psProxy.getPrice () + " " + psProxy.getUPC ());
            return true;
        }
        else if (event.target == sliButton)
        {
             sliProxy = new SaleLineItemProxy (sliText.getText ());
             resultsLabel.setText ("The subtotal for this sale line item is " + sliProxy.subtotal () + ".");
             return true;
        }
        else if (event.target == sButton)
        {
            sProxy = new SaleProxy (sText.getText ());
            resultsLabel.setText ("The total for this sale is " + sProxy.total () + ".");
            return true;
        }
        else
        {
            return false;
        }
    }
}

//  Filename:  BrokerServer.java     Author:  Anthony F. Ortiz
//  This file contains the BrokerServer.  All brokers must register
//  themselves with it (in PFWBroker).  The BrokerServer saves a
//  broker after it registers in a vector.  When a BrokerServer
//  does a commit or rollback, each broker in the vector is called upon to
//  perform the actual commit and rollback on the cache and database.

import java.util.*;

public class BrokerServer
{
    private static BrokerServer instance = new BrokerServer ();
    private Vector brokers = new Vector ();
    private Vector oids = new Vector ();

    //  Private constructor (singelton).
    private BrokerServer ()
    {
    }

    //  Get the only instance of BrokerServer (singelton).
    public static BrokerServer getInstance ()
    {
        return instance;
    }

    //  Register brokers with the BrokerServer.
    public void register (String anOID, Object broker)
    {
        brokers.addElement (broker);
        oids.addElement (anOID);
    }

    //  Commit deletes, inserts, and updates from the cache and
    //  database.
    public void commit ()
    {
        int i = 0;
        while (brokers.size () - 1 >= i)
        {
            PFWBroker pfwBroker = (PFWBroker) brokers.elementAt (i);
            pfwBroker.commit ((String) oids.elementAt (i));
            i++;
        }
    }

    //  Rollback deletes, inserts, and updates from the cache and
    //  database.
    public void rollback ()
    {
        int i = 0;
        while (brokers.size () - 1 >= i)
        {
            PFWBroker pfwBroker = (PFWBroker) brokers.elementAt (i);
            pfwBroker.rollback ((String) oids.elementAt (i));
            i++;
        }
    }
}

//  Filename:  FilePFWBroker.java     Author:  Anthony F. Ortiz
//  This file contains the FilePFWBroker.  It will not be used in the
//  project.

public abstract class FilePFWBroker extends PFWBroker
{
    //  This method will not be used in the project.
    public Object materializeWith (String anOID)
    {
        Object obj = new Object ();
        return obj;
    }

    //  Abstract method.
    public abstract String objectAsRecord (String anOID, Object obj);
}

//  Filename:  IProductSpecification.java     Author:  Anthony F. Ortiz
//  This file contains the interface for ProductSpecifcation and its
//  Proxy.

public interface IProductSpecification
{
    //  Abstract methods (interface).
    public String getDescription ();
    public float getPrice ();
    public int getUPC ();
    public void setDescription (String change);
    public void setPrice (float change);
    public void setUPC (int change);
}

//  Filename:  ISale.java     Author:  Anthony F. Ortiz
//  This file contains the interface for Sale and its Proxy.

public interface ISale
{
    //  Abstract methods (interface).
    public float getBalance ();
    public String getDate ();
    public float total ();
}

//  Filename:  ISaleLineItem.java     Author:  Anthony F. Ortiz
//  This file contains the interface for SaleLineItem and its
//  Proxy.

public interface ISaleLineItem
{
    //  Abstract method (interface).
    public float subtotal ();
}

//  Filename:  ObjectCache.java     Author:  Anthony F. Ortiz
//  This file contains the cache for the ProductSpecification,
//  SaleLineItem, and Sale objects.  The PFWBroker class has a handle to
//  it.  Two hashtables hold the objects and the states of the cached
//  objects.

import java.util.Hashtable;

public class ObjectCache
{
    private Hashtable objects = new Hashtable ();
    private Hashtable states = new Hashtable ();

    //  Add object and it's state to the cache.
    public void add (String anOID, Object obj, String state)
    {
        objects.put (anOID, obj);
        states.put (anOID, state);
    }

    //  Get the object at key, anOID.
    public Object find (String anOID)
    {
        return objects.get ((Object) anOID);
    }

    //  Returns true if key is not in the cache.  Otherwise, it returns
    //  false.
    public boolean isEmpty (String anOID)
    {
        return objects.contains (anOID);
    }

    //  Remove the object and state from the cache at key, anOID.
    public void remove (String anOID)
    {
        objects.remove (anOID);
        states.remove (anOID);
    }

    //  Get the object's state at key, anOID.
    public String getState (String anOID)
    {
        return (String) states.get (anOID);
    }
}

//  Filename:  Payment.java     Author:  Anthony F. Ortiz
//  This file is used by the Sale class.  It's main attribute is amount
//  which is what the customer gives the cashier.  It won't be needed
//  for the project.

public class Payment
{
    private float amount;

    //  Constructor.
    public Payment (float cashTendered)
    {
        this.amount = cashTendered;
    }

    //  Get the amount the customer gives the cashier.
    public float getAmount ()
    {
        return amount;
    }
}

//  Filename:  PFWBroker.java     Author:  Anthony F. Ortiz
//  This file contains the top level broker.  The RelationalPFWBroker
//  inherits from it.  It materializes objects not cached or returns them
//  if they are.  It also performs rollback and commits on the cache
//  and the database.

public abstract class PFWBroker
{
    protected ObjectCache cache = new ObjectCache ();
    protected BrokerServer bServer;
    protected String table = new String ();
    protected final String newclean = "newclean";
    protected final String newdirty = "newdirty";
    protected final String oldclean = "oldclean";
    protected final String olddirty = "olddirty";
    protected final String newdeleted = "newdeleted";
    protected final String olddeleted = "olddeleted";

    //  Register broker with the BrokerServer, see if object is in the
    //  cache.  If it is in the cache, return it.  Otherwise, materialize
    //  it (do a query to the database, cache it, and return it).
    public Object objectWith (String anOID)
    {
        bServer = BrokerServer.getInstance ();
        bServer.register (anOID, this);
        Object obj = inCache (anOID);
        if (obj != null)
        {
            return obj;
        }
        else
        {
            return materializeWith (anOID);
        }
    }

    //  Return the cached object if it is in the cache.
    public Object inCache (String anOID)
    {
        return cache.find (anOID);
    }

    //  Add 'oldclean' to the cache when a new object is inserted from
    //  the database.
    public void addOldClean (String anOID, Object obj)
    {
        if (obj != null)
        {
            cache.add (anOID, obj, oldclean);
        }
    }

    //  Add 'newclean' to the cache when a new object is inserted from
    //  the application.
    public void addNewClean (String anOID, Object obj)
    {
        cache.add (anOID, obj, newclean);
    }

    //  Add 'olddirty' or 'newdirty' to the cache when an object is
    //  updated.
    public void addOldDirtyorNewDirty (String anOID, Object obj)
    {
        if (cache.getState (anOID) == oldclean || cache.getState (anOID) == olddirty)
        {
            cache.add (anOID, obj, olddirty);
        }
        else if (cache.getState (anOID) == newclean || cache.getState (anOID) == newdirty)
        {
            cache.add (anOID, obj, newdirty);
        }
    }

    //  Add 'olddeleted' or 'newdeleted' to the cache when an object is
    //  deleted.
    public void addOldDeletedorNewDeleted (String anOID, Object obj)
    {
        if (cache.getState (anOID) == oldclean || cache.getState (anOID) == olddirty)
        {
            cache.add (anOID, obj, olddeleted);
        }
        else if (cache.getState (anOID) == newclean || cache.getState (anOID) == newdirty)
        {
            cache.add (anOID, obj, newdeleted);
        }
    }

    //  Commit the deletes, inserts, and updates in the cache and
    //  database.
    public void commit (String anOID)
    {
        Object obj = new Object ();
        PostDB db = PostDB.getInstance ();
        String query = new String ();
        if (cache.getState (anOID) == newclean)
        {
            obj = cache.find (anOID);
            addOldClean (anOID, obj);
            query = objectAsRecord (anOID, obj);
            db.update ("insert into " + table + " values " + query);
        }
        else if (cache.getState (anOID) == newdirty) //  same as 'olddirty'.
        {
            obj = cache.find (anOID);
            addOldClean (anOID, obj);
            query = objectAsRecord (anOID, obj);
            db.update ("insert into " + table + " values " + query);
        }
        else if (cache.getState (anOID) == olddirty)
        {
            obj = cache.find (anOID);
            addOldClean (anOID, obj);
            db.update ("delete from " + table + " where OID = " + "'" + anOID + "'");
            query = objectAsRecord (anOID, obj);
            db.update ("insert into " + table + " values " + query);
        }
        else if (cache.getState (anOID) == newdeleted)
        {
            cache.remove (anOID);
        }
        else if (cache.getState (anOID) == olddeleted)
        {
            cache.remove (anOID);
            db.update ("delete from " + table + " where OID = " + "'" + anOID + "'");
        }
    }

    //  Rollback the deletes, inserts, and updates in the cache and
    //  database.
    public void rollback (String anOID)
    {
        if (cache.getState (anOID) == newclean ||
            cache.getState (anOID) == newdirty ||
            cache.getState (anOID) == olddirty ||
            cache.getState (anOID) == newdeleted ||
            cache.getState (anOID) == olddeleted)
        {
            cache.remove (anOID);
        }
    }

    //  Abstract method.
    public abstract Object materializeWith (String anOID);

    //  Abstract method.
    public abstract String objectAsRecord (String anOID, Object obj);
}

//  Filename:  PostDB.java     Author:  Anthony F. Ortiz
//  This file contains the class which will allow the relational database
//  broker to execute SQL queries (select, insert, and delete).  It is
//  a singelton.

import java.net.URL.*;
import exjava.math.*;
import exgwe.sql.*;
import exjava.sql.*;

public class PostDB
{
    private static PostDB instance = new PostDB ();
    private String url = "jdbc:mysql://gold.mcs.csuhayward.edu:3333/postDB";
    private String driverName = "exgwe.sql.gweMysqlDriver";
    private String dbuser = "6310";
    private String dbpass = "6310";
    private Connection con = null;
    private Statement stmt = null;
    private ResultSet rs = null;

    //  Private constructor (singelton).
    private PostDB ()
    {
    }

    //  Get the only instance of PostDB (singelton).
    public static PostDB getInstance ()
    {
        return instance;
    }

    //  Get ResultSet from a sql query.
    public ResultSet execute (String query)
    {
        try
        {
            Class.forName (driverName);
            con = DriverManager.getConnection (url, dbuser, dbpass);
            stmt = con.createStatement ();
            stmt.execute(query);
            rs = stmt.getResultSet ();
            //stmt.close ();
            //con.close ();
            if (rs.next () == false)
            {
                //  This is for objects that are not in the database.
                rs = null;
            }
            return rs;
        }
        catch (Exception e)
        {
                System.out.print (e);
        }
        return null;
    }

    //  Update database (insert or delete).
    public void update (String query)
    {
        try
        {
            Class.forName (driverName);
            con = DriverManager.getConnection (url, dbuser, dbpass);
            stmt = con.createStatement ();
            stmt.executeUpdate(query);
            //stmt.close ();
            //con.close ();
        }
        catch (Exception e)
        {
                System.out.println (e);
        }
    }
}

//  Filename:  ProductSpecification.java     Author:  Anthony F. Ortiz
//  This file contains one of the 3 realSubjects, ProductSpecification.
//  A ProductSpecification has 3 attributes, upc, price, and description.

public class ProductSpecification implements IProductSpecification
{
    private int upc = 0;
    private float price = 0;
    private String description = "";

    //  Constructor.
    public ProductSpecification (int upc, float price, String description)
    {
        this.upc = upc;
        this.price = price;
        this.description = description;
    }

    //  Get upc.
    public int getUPC ()
    {
        return upc;
    }

    //  Get price.
    public float getPrice ()
    {
        return price;
    }

    //  Get description.
    public String getDescription ()
    {
        return description;
    }

    //  Set upc.
    public void setUPC (int change)
    {
        upc = change;
    }

    //  Set price.
    public void setPrice (float change)
    {
        price = change;
    }

    //  Set description.
    public void setDescription (String change)
    {
        description = change;
    }
}

//  Filename:  ProductSpecificationProxy.java     Author:  Anthony F. Ortiz
//  This file contains the proxy for SaleLineItem.

public class ProductSpecificationProxy extends VirtualProxy implements IProductSpecification
{
    //  Constructor.
    public ProductSpecificationProxy (String anOID)
    {
        OID = anOID;
    }

    //  Constructor (inserts, newclean).
    public ProductSpecificationProxy (String anOID, int upc, float price, String description)
    {
        OID = anOID;
        PFWBroker pfwBroker = (PFWBroker) getBroker ();
        ProductSpecification aProductSpec = new ProductSpecification (upc, price, description);
        pfwBroker.addNewClean (OID, aProductSpec);
        BrokerServer bServer = BrokerServer.getInstance ();
        bServer.register (anOID, pfwBroker);
    }

    //  Get description from ProductSpecification (realSubject).
    public String getDescription ()
    {
        ProductSpecification aProductSpec = (ProductSpecification) getRealSubject ();
        return aProductSpec.getDescription ();
    }

    //  Get price from ProductSpecification (realSubject).
    public float getPrice ()
    {
        ProductSpecification aProductSpec = (ProductSpecification) getRealSubject ();
        return aProductSpec.getPrice ();
    }

    //  Get upc from ProductSpecification (realSubject).
    public int getUPC ()
    {
        ProductSpecification aProductSpec = (ProductSpecification) getRealSubject ();
        return aProductSpec.getUPC ();
    }

    //  Create broker for ProductSpecifationProxy.
    public Object createBroker ()
    {
        return ProductSpecificationRelationalBroker.getInstance ();
    }

    //  Set description for ProductSpecification (realSubject).
    public void setDescription (String change)
    {
        ProductSpecification aProductSpec = (ProductSpecification) getRealSubject ();
        aProductSpec.setDescription (change);
        PFWBroker pfwBroker = (PFWBroker) getBroker ();
        pfwBroker.addOldDirtyorNewDirty (OID, aProductSpec);
    }

    //  Set price for ProductSpecification (realSubject).
    public void setPrice (float change)
    {
        ProductSpecification aProductSpec = (ProductSpecification) getRealSubject ();
        aProductSpec.setPrice (change);
        PFWBroker pfwBroker = (PFWBroker) getBroker ();
        pfwBroker.addOldDirtyorNewDirty (OID, aProductSpec);
    }

    //  Set upc for ProductSpecification (realSubject).
    public void setUPC (int change)
    {
        ProductSpecification aProductSpec = (ProductSpecification) getRealSubject ();
        aProductSpec.setUPC (change);
        PFWBroker pfwBroker = (PFWBroker) getBroker ();
        pfwBroker.addOldDirtyorNewDirty (OID, aProductSpec);
    }

    //  Set realSubject to null.  This solves the rollback, set problem.
    public void reset ()
    {
        realSubject = null;
    }

    //  Remove ProductSpecifation.  Change ProductSpecifation (realSubject)
    //  to blanks and change cache state to 'olddeleted' or 'newdeleted'.
    public void remove ()
    {
        ProductSpecification aProductSpec = (ProductSpecification) getRealSubject ();
        aProductSpec.setDescription ("");
        aProductSpec.setPrice ((float) 0.0);
        aProductSpec.setUPC (0);
        PFWBroker pfwBroker = (PFWBroker) getBroker ();
        pfwBroker.addOldDeletedorNewDeleted (OID, aProductSpec);
    }
}

//  Filename:  ProductSpecificationRelationalBroker.java     Author:  Anthony F. Ortiz
//  This file contains the the RelationalBroker for the
//  ProductSpecificationProxy.  It's main function is to return the
//  ProductSpecification from a ResultSet (which came from a database
//  query).  It is a singelton.

public class ProductSpecificationRelationalBroker extends RelationalPFWBroker
{
    private static ProductSpecificationRelationalBroker instance = new ProductSpecificationRelationalBroker ();

    //  Private constructor (singelton).
    private ProductSpecificationRelationalBroker ()
    {
        table = "Products";
    }

    //  Get the only instance of ProductSpecificationRelationalBroker
    //  (singelton).
    public static ProductSpecificationRelationalBroker getInstance ()
    {
        return instance;
    }

    //  Return the current record (ResultSet from a database query).
    public Object currentRecordAsObject ()
    {
        ProductSpecification aProductSpec = new ProductSpecification (Integer.parseInt (currentRecord.field ("upc")), (float) new Double (currentRecord.field ("price")).doubleValue (), currentRecord.field ("description"));
        return aProductSpec;
    }

    //  Return a blank record (there was nothing in the ResultSet).
    public Object blankRecordAsObject ()
    {
        ProductSpecification aProductSpec = new ProductSpecification (0, (float) 0.0, "not in db!");
        return aProductSpec;
    }

    //  Return a query for inserts and deletes.
    public String objectAsRecord (String anOID, Object obj)
    {
        String query = new String ();
        ProductSpecification aProductSpec = (ProductSpecification) obj;
        query = "(" + "'" + anOID + "'," + "'" + aProductSpec.getDescription () + "'," + aProductSpec.getPrice () + "," + aProductSpec.getUPC ()  + ")";
        return query;
    }
}

//  Filename:  RandomNumberGenerator.java     Author:  Anthony F. Ortiz
//  This file contains the class which will generate random OID numbers
//  for inserts of ProductSpecifications into the database.  This class
//  makes it less likely, but not impossible for there to be duplicate
//  OID numbers in the database (Products table).

public class RandomNumberGenerator
{
    //  Get a random number from 1 to 1000000.
    public static String getRandomNumber ()
    {
        String str;
        int i;
        i = (int) (Math.random () * 10000000);
        str = "p" + i;
        return str;
    }
}

//  Filename:  RDBRecord.java     Author:  Anthony F. Ortiz
//  This file contains the class that holds the ResultSet from a
//  database query.

import exgwe.sql.*;
import exjava.sql.*;

public class RDBRecord
{
    public ResultSet record = null;

    //  Get the current record.
    public ResultSet getRecord ()
    {
        return record;
    }

    //  Set the current record.
    public void setRecord (ResultSet arecord)
    {
        record = arecord;
    }

    //  Return the field of a ResultSet which is expressed in the
    //  the parameter fieldName.
    public String field (String fieldName)
    {
        try
        {
            return record.getString (fieldName);
        }
        catch (Exception e)
        {
            System.out.print (e);
        }
        return null;
    }
}

//  Filename:  RelationalPFWBroker.java     Author:  Anthony F. Ortiz
//  This file contains the RelationalPFWBroker.  It materializes the
//  object from the database and returns it (to the proxy).

public abstract class RelationalPFWBroker extends PFWBroker
{
    protected RDBRecord currentRecord = new RDBRecord ();

    //  Materialize an object.  Do a select.  If the object is in the
    //  database, add it to the cache and return the object (to the proxy).
    //  Otherwise, make the object point to a blank record and return it
    //  (to the proxy).
    public Object materializeWith (String anOID)
    {
        Object obj = new Object ();
        obj = selectFirst (anOID);
        if (obj != null)
        {
            obj = currentRecordAsObject ();
            addOldClean (anOID, obj);
        } //  This is for objects that are not in the database.
        else
        {
            obj = blankRecordAsObject ();
        }
        return obj;
    }

    //  Do a query on the database, set currentRecord to this ResultSet,
    //  and return the currentRecord.
    public Object selectFirst (String anOID)
    {
        PostDB db = PostDB.getInstance ();
        currentRecord.setRecord (db.execute ("select * from " + table + " where OID = " + "'" + anOID + "'"));
        return currentRecord.getRecord ();
    }

    //  Abstract method.
    public abstract Object currentRecordAsObject ();

    //  Abstract method.
    public abstract String objectAsRecord (String anOID, Object obj);

    //  Abstract method.
    public abstract Object blankRecordAsObject ();
}

//  Filename:  Sale.java     Author:  Anthony F. Ortiz
//  This file contains one of the 3 realSubjects, Sale.  A Sale has a
//  lineItems, date, time, and payments as attributes.  A Sale's major
//  function is to total all its SaleLineItems.

import java.util.*;

public class Sale implements ISale
{
    private Vector lineItems = new Vector ();
    private String date, time;
    private boolean isComplete = false;
    private Payment payment;

    //  Constructor.
    public Sale (String adate, String atime)
    {
        date = adate;
        time = atime;
    }

    //  Get balance (customer payment - total of SaleLineItems).
    public float getBalance ()
    {
        return payment.getAmount () - total ();
    }

    //  Get date.
    public String getDate ()
    {
        return date + " " + time;
    }

    //  This is not used in class project.
    public void becomeComplete ()
    {
        isComplete = true;
    }

    //  This is not used in class project.
    public boolean isComplete ()
    {
        return isComplete;
    }

    //  Make another SalelineItem.
    public void makeLineItem (String anOID)
    {
        lineItems.addElement (new SaleLineItemProxy (anOID));
    }

    //  Total all the SaleLineItems.
    public float total ()
    {
        float total = 0;
        Enumeration e = lineItems.elements ();
        while (e.hasMoreElements ())
        {
            total += ((SaleLineItemProxy) e.nextElement ()).subtotal ();
        }
        return total;
    }

    //  set customer's payment.
    public void makePayment (float cashTendered)
    {
        payment = new Payment (cashTendered);
    }
}

//  Filename:  SaleLineItem.java     Author:  Anthony F. Ortiz
//  This file contains one of the 3 realSubjects, SaleLineItem.  A
//  SaleLineItem has a quantity and a ProductSpecification as
//  attributes.  It's main function is to get the subtotal of a
//  SaleLineItem (quantity * ProductSpecification price).

public class SaleLineItem implements ISaleLineItem
{
    private int quantity;
    private ProductSpecificationProxy productSpecProxy;

    public SaleLineItem (ProductSpecificationProxy specProxy, int quantity)
    {
        this.productSpecProxy = specProxy;
        this.quantity = quantity;
    }

    public float subtotal ()
    {
        return quantity * productSpecProxy.getPrice ();
    }
}

//  Filename:  SaleLineItemProxy.java     Author:  Anthony F. Ortiz
//  This file contains the proxy for SaleLineItem.

public class SaleLineItemProxy extends VirtualProxy implements ISaleLineItem
{
    //  Constructor.
    public SaleLineItemProxy (String anOID)
    {
        OID = anOID;
    }

    //  Get subtotal for a SaleLineItem (realSubject).
    public float subtotal ()
    {
        SaleLineItem aLineItem = (SaleLineItem) getRealSubject ();
        return aLineItem.subtotal ();
    }

    //  Create broker for a SaleLineItemProxy.
    public Object createBroker ()
    {
        return SaleLineItemRelationalBroker.getInstance ();
    }

    //  This method is not used for the project.
    public void reset ()
    {
    }

    //  This method is not used for the project.
    public void remove ()
    {
    }
}

//  Filename:  SaleLineItemRelationalBroker.java     Author:  Anthony F. Ortiz
//  This file contains the the RelationalBroker for the
//  SaleLineItemProxy.  It's main function is to return the
//  SaleLineItem from a ResultSet (which came from a database
//  query).  It is a singelton.

public class SaleLineItemRelationalBroker extends RelationalPFWBroker
{
    private static SaleLineItemRelationalBroker instance = new SaleLineItemRelationalBroker ();

    //  Private constructor (singelton).
    private SaleLineItemRelationalBroker ()
    {
        table = "Items";
    }

    //  Get the only instance of SaleLineItemRelationalBroker
    //  (singelton).
    public static SaleLineItemRelationalBroker getInstance ()
    {
        return instance;
    }

    //  Return the current record (ResultSet from a database query).
    public Object currentRecordAsObject ()
    {
        ProductSpecificationProxy psProxy = new ProductSpecificationProxy (currentRecord.field ("PSOID"));
        SaleLineItem aLineItem = new SaleLineItem (psProxy, Integer.parseInt (currentRecord.field ("qty")));
        return aLineItem;
    }

    //  Return a blank record (there was nothing in the result set).
    public Object blankRecordAsObject ()
    {
        ProductSpecificationProxy psProxy = new ProductSpecificationProxy ("blank");
        SaleLineItem aLineItem = new SaleLineItem (psProxy, 0);
        return aLineItem;
    }

    //  This method is not used in the project.
    public String objectAsRecord (String anOID, Object obj)
    {
        String query = new String ();
        return query;
    }
}

//  Filename:  SaleProxy.java     Author:  Anthony F. Ortiz
//  This file contains the proxy for Sale.

public class SaleProxy extends VirtualProxy implements ISale
{
    //  Constructor.
    public SaleProxy (String anOID)
    {
        OID = anOID;
    }

    //  Get balance for a Sale (realSubject).
    public float getBalance ()
    {
        Sale aSale = (Sale) getRealSubject ();
        return aSale.getBalance ();
    }

    //  Get the date for a Sale (realSubject).
    public String getDate ()
    {
        Sale aSale = (Sale) getRealSubject ();
        return aSale.getDate ();
    }

    //  Get the total for a Sale (realSubject).
    public float total ()
    {
        Sale aSale = (Sale) getRealSubject ();
        return aSale.total ();
    }

    //  Create broker for the SaleProxy.
    public Object createBroker ()
    {
        return SaleRelationalBroker.getInstance ();
    }

    //  This method is not used for the project.
    public void reset ()
    {
    }

    //  This method is not used for the project.
    public void remove ()
    {
    }
}

//  Filename:  SaleRelationalBroker.java     Author:  Anthony F. Ortiz
//  This file contains the the RelationalBroker for the SaleProxy.  It's
//  main function is to return the Sale from a ResultSet (which came from
//  a database query).  It is a singelton.

import java.net.URL.*;
import exjava.math.*;
import exgwe.sql.*;
import exjava.sql.*;

public class SaleRelationalBroker extends RelationalPFWBroker
{
    private static SaleRelationalBroker instance = new SaleRelationalBroker ();

    //  Private constructor (singelton).
    private SaleRelationalBroker ()
    {
        table = "Sales";
    }

    //  Get the only instance of SaleRelationalBroker (singelton).
    public static SaleRelationalBroker getInstance ()
    {
        return instance;
    }

    //  Return the current record (ResultSet from a database query).
    public Object currentRecordAsObject ()
    {
        Sale aSale = new Sale (currentRecord.field ("saledate"), currentRecord.field ("saletime"));
        PostDB db = PostDB.getInstance ();
        currentRecord.setRecord (db.execute ("select * from " + "SalesItems" + " where SALEOID = " + "'" + currentRecord.field ("OID") + "'"));
        try
        {
            ResultSet rs = currentRecord.getRecord ();
            do
            {
                aSale.makeLineItem (currentRecord.field ("ITEMOID"));
            }
            while (rs.next ());
        }
        catch (Exception e)
        {
                System.out.print (e);
        }
        return aSale;
    }

    //  Return a blank record (there was nothing in the result set).
    public Object blankRecordAsObject ()
    {
        Sale aSale = new Sale ("not in db!", "not in db!");
        return aSale;
    }

    //  This method is not used in the project.
    public String objectAsRecord (String anOID, Object obj)
    {
        String query = new String ();
        return query;
    }
}

//  Filename:  VirtualProxy.java     Author:  Anthony F. Ortiz
//  This file contains the VirtualProxy (on-demand materialization) for the
//  3 proxies, ProductSpecificationProxy, SaleLineItemProxy, and SaleProxy.

public abstract class VirtualProxy
{
    protected String OID;
    protected Object realSubject;
    protected Object broker;

    //  If realSubject is null, materialize realSubject.  Otherwise, return
    //  current realSubject.
    public Object getRealSubject ()
    {
        if (realSubject == null)
        {
            materializeSubject ();
        }
        return realSubject;
    }

    //  Materialize realSubject.  First get the broker.  Then, get the
    //  realSubject from PFWBroker (either the cache or the database).
    public void materializeSubject ()
    {
        PFWBroker pfwBroker;
        pfwBroker = (PFWBroker) getBroker ();
        realSubject = pfwBroker.objectWith (OID);
    }

    //  If broker is null, create a broker.  Otherwise return the current
    //  broker.
    public Object getBroker ()
    {
        if (broker == null)
        {
            broker = createBroker ();
        }
        return broker;
    }

    //  Abstract method.
    public abstract Object createBroker ();

    //  Abstract method.
    public abstract void reset ();

    //  Abstract method.
    public abstract void remove ();
}

//  Outfile:  Prog1.out

//  This program uses a GUI interface.




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