f_stockr.java

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package Middle;

/**
 * Facade for read access to the stock list.
 * The actual implementation of this is held on the middle tier.
 * The actual stock list is held in a relational DataBase on the 
 * third tier.
 * @author  Michael Alexander Smith
 * @version 2.0
 */

import java.rmi.*;
import Catalogue.*;
import Remote.*;
import javax.swing.ImageIcon;

/**
 * Setup connection to the middle tier
 */

public class F_StockR implements StockReader
{
  private RemoteStockR_I aR_StockR   = null;
  private String         theStockURL = null;

  public F_StockR( String url )
  {
    System.out.println("F_StockR: " + url );
    theStockURL = url;
  }
  
  private void connect() throws StockException
  {
    try                                             // Setup
    {                                               //  connection
      aR_StockR =                                   //  Connect to
        (RemoteStockR_I) Naming.lookup(theStockURL);// Stub returned
    }
    catch ( Exception e )                           // Failure to
    {                                               //  attach to the
      aR_StockR = null;
      throw new StockException( "Com: " + 
                                e.getMessage()  );  //  object
      
    }
  }

  /**
   * Checks if the product exits in the stock list
   * @return true if exists otherwise false
   */

  public synchronized boolean exists( String number )
         throws StockException
  {
    System.out.println("F_StockR:exists() " );
    try
    {
      if ( aR_StockR == null ) connect();
      return aR_StockR.exists( number );
    } catch ( RemoteException e )
    {
      aR_StockR = null;
      throw new StockException( "Net: " + e.getMessage() );
    }
  }

  /**
   * Returns details about the product in the stock list
   * @return StockNumber, Description, Price, Quantity
   */

  public synchronized Product getDetails( String number )
         throws StockException
  {
    System.out.println("F_StockR:getDetails() " );
    try
    {
      if ( aR_StockR == null ) connect();
      return aR_StockR.getDetails( number );
    } catch ( RemoteException e )
    {
      aR_StockR = null;
      throw new StockException( "Net: " + e.getMessage() );
    }
  }
  
  
  public synchronized ImageIcon getImage( String number )
         throws StockException
  {
    System.out.println("F_StockR:getImage() " );
    try
    {
      if ( aR_StockR == null ) connect();
      return aR_StockR.getImage( number );
    }
    catch ( RemoteException e )
    {
      aR_StockR = null;
      throw new StockException( "Net: " + e.getMessage() );
    }
  }

}