CONTROLE - CONVERSOR DE TEMPERATURA

package conversor;

import java.awt.Button;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;
import java.text.DecimalFormat;

public class Controle implements WindowListener, ActionListener {

    private Interface gi;
    private Modelo mo;
    private boolean erro;

    public Controle() {
        gi = new Interface();
        mo = new Modelo();
        gi.setVisible(true);
        gi.addWindowListener(this);
        gi.setActionListener(this);

    }

    public static void main(String[] args) {
        Controle con = new Controle();
    }

    @Override
    public void windowOpened(WindowEvent e) {
    }

    @Override
    public void windowClosing(WindowEvent e) {
        gi.dispose();
    }

    @Override
    public void windowClosed(WindowEvent e) {
    }

    @Override
    public void windowIconified(WindowEvent e) {
    }

    @Override
    public void windowDeiconified(WindowEvent e) {
    }

    @Override
    public void windowActivated(WindowEvent e) {
    }

    @Override
    public void windowDeactivated(WindowEvent e) {
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        Button btnAcao = (Button) e.getSource();
        Double val = string2Double(gi.getTxtTemperatura());
        if (erro) {
            gi.exibeErro();
        } else {
            if (btnAcao.getActionCommand().equals("C")) {
                mo.setCel(val);
                gi.exibeLabels("ºC", mo.getFah(), mo.getKel());
            } else if (btnAcao.getActionCommand().equals("F")) {
                mo.setFah(val);
                gi.exibeLabels("ºF", mo.getCel(), mo.getKel());
            } else if (btnAcao.getActionCommand().equals("K")) {
                mo.setKel(val);
                gi.exibeLabels("K", mo.getCel(), mo.getFah());
            }
        }

    }

    public double string2Double(String a) {
        double res = 0;
        try {
            erro = false;
            res = Double.parseDouble(a);
        } catch (NumberFormatException e) {
            erro = true;
        }
        return res;
    }
}