bookpricescreen.java

java web services how to program

// Fig. 16.19: BookPriceScreen.java
// BookPriceScreen is a MIDlet screen that invokes the Best Book
// Price Web service and displays its results.
package jws1casestudy.clients.j2me;

// import J2ME packages
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

class BookPriceScreen extends Form {

   // create Form for specifying ISBN of book to obtain price
   BookPriceScreen( final Display display )
   {
      super( "Select book to obtain price" );

      // ChoiceGroup that enables user to specify book ISBN
      final ChoiceGroup choices = 
         new ChoiceGroup( "", ChoiceGroup.EXCLUSIVE );
      choices.append( "0130895725", null );
      choices.append( "0130284181", null );
      choices.append( "0130341517", null );
      choices.append( "0130293636", null );
      choices.append( "0130895601", null );
      append( choices );

      // create soft button commands
      Command invokeCommand = 
         new Command( "Select", Command.OK, 0 );
      addCommand( invokeCommand );

      Command backCommand = 
         new Command( "Back", Command.BACK, 1 );
      addCommand( backCommand );

      // allow soft button access
      setCommandListener(
         new CommandListener() {

            // invoked when user presses soft button
            public void commandAction( 
               Command command, Displayable displayable )
            {
               // invoke service if user presses Select
               if ( command.getCommandType() == Command.OK ) {

                  BookPriceService priceService = 
                     new BookPriceService();

                  // invoke Web service through interface
                  int selection = choices.getSelectedIndex();
                  String isbn = choices.getString( selection );

                  // invoke Best Book Price Web service
                  PriceQuote quote = 
                     priceService.getBestPrice( isbn );

                  // display PriceQuote results on success
                  if ( quote != null )
                     display.setCurrent( new ResultScreen( 
                        quote, display ) );

                  // display error page on failure
                  else
                  {
                     Alert errorPage = new Alert( "Error",
                        "Cannot invoke Web Service", null, 
                        AlertType.ERROR );
                     errorPage.setTimeout( 3000 );
                     display.setCurrent( errorPage );
                  }
               }

               // display mainScreen if user presses Back
               else if ( command.getCommandType() == 
                  Command.BACK )

                  display.setCurrent( new MainScreen( display ) );

            } // end method commandAction

         } // end anonymous inner class
      );

   } // end BookPriceScreen constructor

   // create Form to display book information
   private class ResultScreen extends Form {
      private PriceQuote priceQuote;

      ResultScreen( PriceQuote quote, final Display display )
      {
         super( "Best price" );
         priceQuote = quote;

         // include book title on Form
         append( new StringItem( "", "Price: " + 
            priceQuote.getPrice() + '\n' ) );

         // include book ISBN on Form
         append( new StringItem( "", "ISBN: " + 
            priceQuote.getIsbn() + '\n'  ) );

         // include book authors on Form
         append( new StringItem( "", 
            "Store Description: " + 
            priceQuote.getStoreDescription() ) );

         // create soft button commands
         Command okCommand = 
            new Command( "Order", Command.OK, 0 );
         addCommand( okCommand );

         // create soft button commands
         Command cancelCommand = 
            new Command( "Cancel", Command.CANCEL, 1 );
         addCommand( cancelCommand );

         // allow soft button access for this Screen
         setCommandListener(
            new CommandListener() {

               // invoked when user presses soft button
               public void commandAction( 
                  Command command, Displayable displayable )
               {
                  Screen displayScreen = null;

                  // display order screen if user presses Order
                  if ( command.getCommandType() == Command.OK ) {
                     displayScreen = new BookPurchaseScreen( 
                        priceQuote, display );
                  }

                  // display mainScreen if user presses Cancel
                  else if ( command.getCommandType() == 
                     Command.CANCEL )

                     displayScreen = new MainScreen( display );

                  display.setCurrent( displayScreen );
               }
            }
         );

      } // end ResultScreen constructor

   } // end class ResultScreen

} // end class BookPriceScreen