// Fig. 14.37: FileDemonstration.java
// Demonstrating the File class.
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;

public class FileDemonstration extends JFrame
{
   private JTextArea outputArea; // used for output
   private JScrollPane scrollPane; // used to provide scrolling to output
   
   // set up GUI
   public FileDemonstration()
   {
      super( "Testing class File" );

      outputArea = new JTextArea();

      // add outputArea to scrollPane
      scrollPane = new JScrollPane( outputArea ); 

      add( scrollPane, BorderLayout.CENTER ); // add scrollPane to GUI

      setSize( 400, 400 ); // set GUI size
      setVisible( true ); // display GUI

      analyzePath(); // create and analyze File object
   } // end FileDemonstration constructor

   // allow user to specify file name
   private File getFile()
   {
      // display file dialog, so user can choose file to open
      JFileChooser fileChooser = new JFileChooser();
      fileChooser.setFileSelectionMode(
         JFileChooser.FILES_AND_DIRECTORIES );

      int result = fileChooser.showOpenDialog( this );

      // if user clicked Cancel button on dialog, return
      if ( result == JFileChooser.CANCEL_OPTION )
         System.exit( 1 );

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

      // display error if invalid
      if ( ( fileName == null ) || ( fileName.getName().equals( "" ) ) )
      {
         JOptionPane.showMessageDialog( this, "Invalid File Name",
            "Invalid File Name", JOptionPane.ERROR_MESSAGE );
         System.exit( 1 );
      } // end if

      return fileName;
   } // end method getFile

   // display information about file user specifies
   public void analyzePath()
   {
      // create File object based on user input
      File name = getFile();

      if ( name.exists() ) // if name exists, output information about it
      {
         // display file (or directory) information
         outputArea.setText( String.format(
            "%s%s\n%s\n%s\n%s\n%s%s\n%s%s\n%s%s\n%s%s\n%s%s",
            name.getName(), " exists",
            ( name.isFile() ? "is a file" : "is not a file" ),
            ( name.isDirectory() ? "is a directory" : 
               "is not a directory" ),
            ( name.isAbsolute() ? "is absolute path" : 
               "is not absolute path" ), "Last modified: ",
            name.lastModified(), "Length: ", name.length(), 
            "Path: ", name.getPath(), "Absolute path: ",
            name.getAbsolutePath(), "Parent: ", name.getParent() ) );

         if ( name.isDirectory() ) // output directory listing
         {
            String directory[] = name.list();
            outputArea.append( "\n\nDirectory contents:\n" );
   
            for ( String directoryName : directory )
               outputArea.append( directoryName + "\n" );
         } // end else
      } // end outer if
      else // not file or directory, output error message
      {
         JOptionPane.showMessageDialog( this, name +
            " does not exist.", "ERROR", JOptionPane.ERROR_MESSAGE );
      } // end else  
   } // end method analyzePath
} // end class FileDemonstration

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