private void constructMenubar() {
		// File
		JMenu filemenu = new JMenu("Datei");
		filemenu.add(new AbstractAction("Neue IP-Adresse"){
		    @Override
		    public void actionPerformed(ActionEvent ae) {
			    new IpaddrHandler(_c, controller);
		    }
		});
		
		filemenu.addSeparator();
		
		filemenu.add(new AbstractAction("\u00dcber ...") {
		    @Override
		    public void actionPerformed(ActionEvent e) {
			    JOptionPane.showMessageDialog(_frame, "ClassroomController\n(c) Copyright 2015 \n Julien Schroeter, Timo Bauer", "\u00dcber ClassroomController", JOptionPane.PLAIN_MESSAGE);
		    }
		});
		
		/*filemenu.add(new AbstractAction("Einstellungen"){
		   @Override
		   public void actionPerformed(ActionEvent ae) {
		       
		   }
		});*/
		
		filemenu.addSeparator();
		
		filemenu.add(new AbstractAction("Beenden") {
		    @Override
		    public void actionPerformed(ActionEvent ae) {
                try {
                    _c.close();
                } catch (SQLException ex) {
                    ex.printStackTrace();
                } finally {
                    System.exit(0);
                }
            }
		});
		
		_menubar.add(filemenu);
		
		
		// Edit
		JMenu editmenu = new JMenu("Bearbeiten");
		editmenu.add(new AbstractAction("IP-Adresse bearbeiten"){
		    @Override
		    public void actionPerformed(ActionEvent ae) {
                if(_ipTbl.getSelectedRowCount() < 1) {
                    JOptionPane.showMessageDialog(_frame, "Bitte w\u00e4hlen Sie einen Eintrag aus.", "Fehler", JOptionPane.ERROR_MESSAGE);
                } else if(_ipTbl.getSelectedRowCount() > 1) {
                    JOptionPane.showMessageDialog(_frame, "Sie können nur einen Eintrag bearbeiten.", "Fehler", JOptionPane.ERROR_MESSAGE);
                } else {
                    int id = (Integer)_ipTbl.getValueAt(
                        _ipTbl.getSelectedRow(),
                        0);
                    try {
                        PreparedStatement psGetEntry = _c.prepareStatement("SELECT * FROM `IP_ADDR` WHERE `ID`=?");
                        psGetEntry.setInt(1, id);
                        ResultSet rsEntry = psGetEntry.executeQuery();
                        IPAddr ipEntry = null;
                        while(rsEntry.next()) {
                            ipEntry = new IPAddr(
                                rsEntry.getInt("ID"),
                                rsEntry.getString("IP_ADDR"),
                                rsEntry.getString("NOTES"),
                                rsEntry.getBoolean("STATUS"));
                        }
                        new IpaddrHandler(_c, controller, ipEntry);
                    } catch (SQLException e) {
                        e.printStackTrace();
                    }
                }
		    }
		});
		
		editmenu.add(new AbstractAction("IP-Adresse l\u00f6schen"){
		    @Override
		    public void actionPerformed(ActionEvent ae) {
                if(_ipTbl.getSelectedRowCount() < 1) {
                    JOptionPane.showMessageDialog(_frame, "Bitte w\u00e4hlen Sie einen Eintrag aus.", "Fehler", JOptionPane.ERROR_MESSAGE);
                } else {
                    int deleteConfirmation = JOptionPane.showConfirmDialog(_frame, "Wollen Sie die ausgew\u00e4lte(n) IP-Adresse(n) wirklich l\u00f6schen?", "Best\u00e4tigung erforderlich", JOptionPane.YES_NO_OPTION);
                    if(deleteConfirmation == JOptionPane.OK_OPTION) {
                        for(int r : _ipTbl.getSelectedRows()) {
                            int id = (Integer) _ipTbl.getValueAt(r, 0);

                            try {
                                PreparedStatement psDeleteEntry = _c.prepareStatement("DELETE FROM `IP_ADDR` WHERE `ID`=?");
                                psDeleteEntry.setInt(1, id);
                                psDeleteEntry.execute();
                            } catch (SQLException e) {
                                e.printStackTrace();
                            }
                        }
                        controller.initializeData();
                    }
                }
            }
        });
		
		
		_menubar.add(editmenu);
		
		// Command
		JMenu commandmenu = new JMenu("Befehl");
		commandmenu.add(new AbstractAction("Befehl ausf\u00fchren") {
		    @Override
		    public void actionPerformed(ActionEvent ae) {
			    CommandExec cmdExec = new CommandExec(_c);
                cmdExec.showSelection();
		    }
		});
		
		commandmenu.add(new AbstractAction("Befehle verwalten"){
		    @Override
		    public void actionPerformed(ActionEvent ae) {
			    new CommandManager(_c);
		    }
		});

        commandmenu.addSeparator();

        commandmenu.add(new AbstractAction("Clientsoftware aktualisieren") {
            @Override
            public void actionPerformed(ActionEvent actionEvent) {
                new ClientUpdate(_c);
            }
        });
		
		_menubar.add(commandmenu);
    }