franta-hg@19: package cz.frantovo.příklady;
franta-hg@19: 
franta-hg@19: /**
franta-hg@19:  * This program is free software: you can redistribute it and/or modify
franta-hg@19:  * it under the terms of the GNU General Public License as published by
franta-hg@19:  * the Free Software Foundation, either version 3 of the License, or
franta-hg@19:  * (at your option) any later version.
franta-hg@19:  *
franta-hg@19:  * This program is distributed in the hope that it will be useful,
franta-hg@19:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
franta-hg@19:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
franta-hg@19:  * GNU General Public License for more details.
franta-hg@19:  *
franta-hg@19:  * You should have received a copy of the GNU General Public License
franta-hg@19:  * along with this program. If not, see <http://www.gnu.org/licenses/>.
franta-hg@19:  */
franta-hg@19: import java.awt.GridLayout;
franta-hg@19: import java.awt.HeadlessException;
franta-hg@19: import java.awt.event.ActionEvent;
franta-hg@19: import java.awt.event.ActionListener;
franta-hg@19: import java.util.ArrayList;
franta-hg@19: import java.util.Collections;
franta-hg@19: import java.util.List;
franta-hg@19: import javax.swing.JButton;
franta-hg@19: import javax.swing.JFrame;
franta-hg@19: import javax.swing.JLabel;
franta-hg@19: import javax.swing.JTextField;
franta-hg@19: 
franta-hg@19: /**
franta-hg@19:  * @author Ing. František Kučera (frantovo.cz)
franta-hg@19:  */
franta-hg@19: public class Caesar extends JFrame {
franta-hg@19: 
franta-hg@19: 	private JTextField prostýText = new JTextField();
franta-hg@19: 	private JTextField šifrovanýText = new JTextField();
franta-hg@19: 	private JButton šifruj = new JButton("Šifruj");
franta-hg@19: 	private JButton dešifruj = new JButton("Dešifruj");
franta-hg@19: 	private static final char[] ABECEDA_ZNAKY = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".toCharArray();
franta-hg@19: 	private static final List<Character> ABECEDA;
franta-hg@19: 	private static final int SKOK = 3;
franta-hg@19: 
franta-hg@19: 	static {
franta-hg@19: 		List<Character> abeceda = new ArrayList<>();
franta-hg@19: 		for (char z : ABECEDA_ZNAKY) {
franta-hg@19: 			abeceda.add(z);
franta-hg@19: 		}
franta-hg@19: 		ABECEDA = Collections.unmodifiableList(abeceda);
franta-hg@19: 	}
franta-hg@19: 
franta-hg@19: 	public static void main(String[] args) {
franta-hg@19: 		Caesar c = new Caesar();
franta-hg@19: 		c.setVisible(true);
franta-hg@19: 	}
franta-hg@19: 
franta-hg@19: 	public Caesar() throws HeadlessException {
franta-hg@19: 		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
franta-hg@19: 		setTitle("Caesarova šifra");
franta-hg@19: 		setLocationRelativeTo(null);
franta-hg@19: 		setLayout(new GridLayout(3, 2));
franta-hg@19: 		
franta-hg@19: 		add(new JLabel("Prostý text"));
franta-hg@19: 		add(prostýText);
franta-hg@19: 
franta-hg@19: 		add(new JLabel("Šifrovaný text"));
franta-hg@19: 		add(šifrovanýText);
franta-hg@19: 
franta-hg@19: 		add(šifruj);
franta-hg@19: 		add(dešifruj);
franta-hg@19: 
franta-hg@19: 		šifruj.addActionListener(new ActionListener() {
franta-hg@19: 			@Override
franta-hg@19: 			public void actionPerformed(ActionEvent e) {
franta-hg@19: 				šifrovanýText.setText(posuň(prostýText.getText(), SKOK));
franta-hg@19: 			}
franta-hg@19: 		});
franta-hg@19: 
franta-hg@19: 		dešifruj.addActionListener(new ActionListener() {
franta-hg@19: 			@Override
franta-hg@19: 			public void actionPerformed(ActionEvent e) {
franta-hg@19: 				prostýText.setText(posuň(šifrovanýText.getText(), -SKOK));
franta-hg@19: 			}
franta-hg@19: 		});
franta-hg@19: 
franta-hg@19: 		pack();
franta-hg@19: 	}
franta-hg@19: 
franta-hg@19: 	private static String posuň(String text, int oKolik) {
franta-hg@19: 		StringBuilder posunutý = new StringBuilder(text.length());
franta-hg@19: 
franta-hg@19: 		for (char z : text.toCharArray()) {
franta-hg@19: 			posunutý.append(posuň(z, oKolik));
franta-hg@19: 		}
franta-hg@19: 
franta-hg@19: 		return posunutý.toString();
franta-hg@19: 	}
franta-hg@19: 
franta-hg@19: 	private static char posuň(char znak, int oKolik) {
franta-hg@19: 		int původníPozice = ABECEDA.indexOf(znak);
franta-hg@19: 
franta-hg@19: 		if (původníPozice < 0) {
franta-hg@19: 			return znak;
franta-hg@19: 		} else {
franta-hg@19: 			int nováPozice = (původníPozice + oKolik) % ABECEDA_ZNAKY.length;
franta-hg@19: 			nováPozice = nováPozice < 0 ? ABECEDA_ZNAKY.length + nováPozice : nováPozice;
franta-hg@19: 			return ABECEDA.get(nováPozice);
franta-hg@19: 		}
franta-hg@19: 	}
franta-hg@19: }