単純なプログラムを書換えよう（Java編）−アウタークラス

二つあるソース(View.java，Main.java）を一つ(Main.java)にします．

//Main.java
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowEvent;
import java.awt.event.WindowAdapter;

class View extends WindowAdapter implements ActionListener{
  private Label value=new Label("0");

  public View(){
    Frame frame=new Frame();
    Panel buttons=new Panel();
    Button inc=new Button("inc");
    Button dec=new Button("dec");
    buttons.add(inc);
    buttons.add(dec);
    inc.addActionListener(this);
    dec.addActionListener(this);
    frame.add(buttons,BorderLayout.SOUTH);
    frame.add(value,BorderLayout.CENTER);
    frame.addWindowListener(this);
    frame.pack();
    frame.show();
  }

  public void actionPerformed(ActionEvent actionEvent){
    if(actionEvent.getActionCommand()=="inc"){
      value.setText(Integer.toString(Integer.parseInt(value.getText())+1));
    }
    else{
      value.setText(Integer.toString(Integer.parseInt(value.getText())-1));
    }
  }
  public void windowClosing(WindowEvent windowEvent){
    System.exit(0);
  }
}

public class Main{
  public static void main(String[] args){
    View view=new View();
  }
}
//end