// Fig. 17.13: CreateRandomFile.java
// Creates random-access file by writing 100 empty records to disk.
import java.io.*;
import javax.swing.*;

import com.deitel.jhtp5.ch17.RandomAccessAccountRecord;

public class CreateRandomFile {
    
    private static final int NUMBER_RECORDS = 100;

   // enable user to select file to open
   private void createFile()
   {
      // display dialog so user can choose file
      JFileChooser fileChooser = new JFileChooser();
      fileChooser.setFileSelectionMode( JFileChooser.FILES_ONLY );

      int result = fileChooser.showSaveDialog( null );
   
      // if user clicked Cancel button on dialog, return
      if ( result == JFileChooser.CANCEL_OPTION )
         return;

      // obtain selected file
      File fileName = fileChooser.getSelectedFile(); 

      // display error if file name invalid
      if ( fileName == null || fileName.getName().equals( "" ) )
         JOptionPane.showMessageDialog( null, "Invalid File Name", 
            "Invalid File Name", JOptionPane.ERROR_MESSAGE );

      else {

         // open file
         try {           
            RandomAccessFile file = 
               new RandomAccessFile( fileName, "rw" );

            RandomAccessAccountRecord blankRecord = 
               new RandomAccessAccountRecord();

            // write 100 blank records
            for ( int count = 0; count < NUMBER_RECORDS; count++ )
               blankRecord.write( file );

            file.close(); // close file

            // display message that file was created
            JOptionPane.showMessageDialog( null, "Created file " + 
               fileName, "Status", JOptionPane.INFORMATION_MESSAGE );

            System.exit( 0 );  // terminate program

         } // end try

         // process exceptions during open, write or close file operations
         catch ( IOException ioException ) {
            JOptionPane.showMessageDialog( null, "Error processing file",
               "Error processing file", JOptionPane.ERROR_MESSAGE );

            System.exit( 1 );
         }

      } // end else

   } // end method createFile

   public static void main( String args[] )
   {
      CreateRandomFile application = new CreateRandomFile();
      application.createFile();
   }   

} // end class CreateRandomFile


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