import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Regex extends JFrame  {

  private final int fontsize = 24;

  private JTextField tRegex = new JTextField("[A-D]{1}[bce-h]{1,5}");
  private JTextField tEingabe = new JTextField("Abc");
  private JTextField tErgebnis = new JTextField();
  
  public Regex () {
    setGUI();
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setVisible(true);
  }

  private void setGUI() {
     setLocation(200,200);
     setSize(600, 350);
     setTitle("Test mit regulären Ausdrücken");
     this.getContentPane().setLayout( new GridBagLayout() );

    // --------------------------------
    
    JLabel label1 = new JLabel("Regulärer Ausdruck");
    add(label1,
           new GridBagConstraints(0, 0, 1, 1, 0.0, 0.0
            ,GridBagConstraints.NORTHEAST, GridBagConstraints.NONE,
            new Insets(30,10,0,10), 0, 0));

    add(tRegex,
           new GridBagConstraints(1, 0, 1, 1, 100.0, 0.0
            ,GridBagConstraints.WEST, GridBagConstraints.HORIZONTAL,
            new Insets(30,10,0,10), 0, 0));

    label1.setFont( new Font("Arial", Font.BOLD,fontsize)  );
    tRegex.setFont( new Font("Arial", Font.PLAIN,fontsize)  );



    // -----------------------------------


    JLabel label2 = new JLabel("Eingabetext");
    add(label2,
            // 0, 0, 1, 1, 0.0, 0.0   Gridx, Gridy,  Columns, Rows, Weightx, weighty
           new GridBagConstraints(0, 1, 1, 1, 0.0, 0.0
            ,GridBagConstraints.WEST, GridBagConstraints.NONE,
            new Insets(30,10,0,10), 0, 0));
        // 30,10,0,10    Ränder: Top, Left, Bottom, Right

    add(tEingabe,
           new GridBagConstraints(1, 1, 1, 1, 100.0, 0.0
            ,GridBagConstraints.NORTHEAST, GridBagConstraints.HORIZONTAL,
            new Insets(30,10,0,10), 0, 0));

    label2.setFont( new Font("Arial", Font.BOLD,fontsize)  );
    tEingabe.setFont( new Font("Arial", Font.PLAIN,fontsize)  );

        
    JLabel label3 = new JLabel("Ergebnis");
    add(label3,
           new GridBagConstraints(0, 3, 1, 1, 0.0, 0.0
            ,GridBagConstraints.WEST, GridBagConstraints.NONE,
            new Insets(60,10,0,10), 0, 0));  
    add(tErgebnis,
           new GridBagConstraints(1, 3, 1, 1, 100.0, 0.0
            ,GridBagConstraints.NORTHEAST, GridBagConstraints.HORIZONTAL,
            new Insets(60,10,0,10), 0, 0));

    label3.setFont( new Font("Arial", Font.BOLD,fontsize)  );
    tErgebnis.setFont( new Font("Arial", Font.PLAIN,fontsize)  );
        
    // Schalter
   JButton  bnAction = new JButton("Check");
   bnAction.setFont( new Font("Arial", Font.BOLD,fontsize+2)  );
   JPanel pn = new JPanel();
    pn.setLayout( new FlowLayout() );
    pn.add(bnAction);

    add(pn,
           new GridBagConstraints(0, 4, 2, 1, 1.0, 0.0
            ,GridBagConstraints.WEST, GridBagConstraints.HORIZONTAL,
            new Insets(30,0,0,0), 0, 0));

    // Verbinden des Schalters mit der Methode "bnAction_Click"
    bnAction.addActionListener(new java.awt.event.ActionListener() {
      public void actionPerformed(ActionEvent e) {
        bnAction_Click();
      }
    });
    
    // wenn in der Eingabezeile die return-Taste gedrückt wird
    tEingabe.addActionListener(new java.awt.event.ActionListener() {
      public void actionPerformed(ActionEvent e) {
        bnAction_Click();
      }
    });
    
    tRegex.addActionListener(new java.awt.event.ActionListener() {
      public void actionPerformed(ActionEvent e) {
        bnAction_Click();
      }
    });
    

  } // setGUI

private void bnAction_Click() {
   try {
   String maske = tRegex.getText();
   String text = tEingabe.getText();
   // 
//   if (   Pattern.matches( maske, text) ) 
   if (text.matches(maske))
     tErgebnis.setText("alles okay");
   else
     tErgebnis.setText("Fehlerhafter Text");
   }
  catch (Exception e ) {
    System.err.println(e.toString());
    tErgebnis.setText(e.toString());
  }
}

  public static void main(String[] args) {
     new Regex();
    
 }

}  // class