handleporn.java

书上的例子

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

public class HandlePOrN implements ActionListener {
    LinkedList<String> list;
    JTextField resultShow, showComputerProcess;

    HandlePOrN(LinkedList<String> list, JTextField t1, JTextField t2) {
        this.list = list;
        resultShow = t1;
        showComputerProcess = t2;
    }

    public void actionPerformed(ActionEvent e) {
        if (list.size() == 1) {
            String number1 = list.getFirst();
            try {
                double d = Double.parseDouble(number1);
                d = -1 * d;
                String str = String.valueOf(d);
                list.set(0, str);
                resultShow.setText(str);
                showComputerProcess.setText("" + list.get(0));
            } catch (Exception ex) {}
        } else if (list.size() == 3) {
            String number2 = list.getLast();
            try {
                double d = Double.parseDouble(number2);
                d = -1 * d;
                String str = String.valueOf(d);
                list.set(2, str);
                resultShow.setText(str);
                showComputerProcess.setText("" + list.get(0) + " " + list.get(1) +
                    " " + list.get(2));
            } catch (Exception ex) {}
        }
    }
}