// Fig. 23.3: HashtableTest.java
// Demonstrates class Hashtable of the java.util package.
import java.util.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class HashtableTest extends JFrame {

   public HashtableTest()
   {
      super( "Hashtable Example" );

      final JLabel status = new JLabel();
      final Hashtable table = new Hashtable();
      final JTextArea display = new JTextArea( 4, 20 );
      display.setEditable( false );

      JPanel northPanel = new JPanel();
      northPanel.setLayout( new BorderLayout() );
      JPanel northSubPanel = new JPanel();
      northSubPanel.add( new JLabel( "First name" ) );
      final JTextField fName = new JTextField( 8 );
      northSubPanel.add( fName );

      northSubPanel.add( new JLabel( "Last name (key)" ) );
      final JTextField lName = new JTextField( 8 );
      northSubPanel.add( lName );
      northPanel.add( northSubPanel, BorderLayout.NORTH );
      northPanel.add( status, BorderLayout.SOUTH );

      JPanel southPanel = new JPanel();
      southPanel.setLayout( new GridLayout( 2, 5 ) );
      JButton put = new JButton( "Put" );
      put.addActionListener(
         new ActionListener() {
            public void actionPerformed( ActionEvent e )
            {
               Employee emp = new Employee(
                  fName.getText(), lName.getText() );
               Object val = table.put( lName.getText(), emp );

               if ( val == null )
                  status.setText( "Put: " + emp.toString() );
               else
                  status.setText( "Put: " + emp.toString() +
                     "; Replaced: " + val.toString() );                     
            }
         }
      );
      southPanel.add( put );

      JButton get = new JButton( "Get" );
      get.addActionListener(
         new ActionListener() {
            public void actionPerformed( ActionEvent e )
            {
               Object val = table.get( lName.getText() );
             
               if ( val != null )
                  status.setText( "Get: " + val.toString() );
               else
                  status.setText( "Get: " + lName.getText() +                     
                                  " not in table" );
            }
         }
      );
      southPanel.add( get );

      JButton remove = new JButton( "Remove" );
      remove.addActionListener(
         new ActionListener() {
            public void actionPerformed( ActionEvent e )
            {
               Object val = table.remove( lName.getText() );
             
               if ( val != null )
                  status.setText( "Remove: " + 
                                  val.toString() );
               else
                  status.setText( "Remove: " + 
                     lName.getText() + " not in table" );                     
            }
         }
      );
      southPanel.add( remove );

      JButton empty = new JButton( "Empty" );
      empty.addActionListener(
         new ActionListener() {
            public void actionPerformed( ActionEvent e )
            {
               status.setText( "Empty: " + table.isEmpty() );
            }
         }
      );
      southPanel.add( empty );

      JButton containsKey = new JButton( "Contains key" );
      containsKey.addActionListener(
         new ActionListener() {
            public void actionPerformed( ActionEvent e )
            {
               status.setText( "Contains key: " +
                  table.containsKey( lName.getText() ) );
            }
         }
      );
      southPanel.add( containsKey );

      JButton clear = new JButton( "Clear table" );
      clear.addActionListener(
         new ActionListener() {
            public void actionPerformed( ActionEvent e )
            {
               table.clear();
               status.setText( "Clear: Table is now empty" );
            }
         }
      );
      southPanel.add( clear );

      JButton listElems = new JButton( "List objects" );
      listElems.addActionListener(
         new ActionListener() {
            public void actionPerformed( ActionEvent e )
            {
               StringBuffer buf = new StringBuffer();

               for ( Enumeration enum = table.elements();
                     enum.hasMoreElements(); )
                  buf.append(
                     enum.nextElement() ).append( '\n' );

               display.setText( buf.toString() );
            }
         }
      );
      southPanel.add( listElems );

      JButton listKeys = new JButton( "List keys" );
      listKeys.addActionListener(
         new ActionListener() {
            public void actionPerformed( ActionEvent e )
            {
               StringBuffer buf = new StringBuffer();

               for ( Enumeration enum = table.keys();
                     enum.hasMoreElements(); )
                  buf.append(
                     enum.nextElement() ).append( '\n' );

                  JOptionPane.showMessageDialog( null,
                     buf.toString(), "Display",
                     JOptionPane.PLAIN_MESSAGE );
            }
         }
      );
      southPanel.add( listKeys );
      Container c = getContentPane();
      c.add( northPanel, BorderLayout.NORTH );
      c.add( new JScrollPane( display ), BorderLayout.CENTER );
      c.add( southPanel, BorderLayout.SOUTH );

      setSize( 540, 300 );
      show();
   }

   public static void main( String args[] )
   {
      HashtableTest app = new HashtableTest();

      app.addWindowListener(
         new WindowAdapter() {
            public void windowClosing( WindowEvent e )
            {
               System.exit( 0 );
            }
         }
      );
   }
}

class Employee {
   private String first, last;

   public Employee( String fName, String lName )
   {
      first = fName;
      last = lName;
   }

   public String toString() { return first + " " + last; }
}

/**************************************************************************
 * (C) Copyright 1999 by Deitel & Associates, Inc. and Prentice Hall.     *
 * All Rights Reserved.                                                   *
 *                                                                        *
 * DISCLAIMER: The authors and publisher of this book have used their     *
 * best efforts in preparing the book. These efforts include the          *
 * development, research, and testing of the theories and programs        *
 * to determine their effectiveness. The authors and publisher make       *
 * no warranty of any kind, expressed or implied, with regard to these    *
 * programs or to the documentation contained in these books. The authors *
 * and publisher shall not be liable in any event for incidental or       *
 * consequential damages in connection with, or arising out of, the       *
 * furnishing, performance, or use of these programs.                     *
 *************************************************************************/