Command模式2例子

//[C] 2002 Sun Microsystems, Inc.---   
import java.awt.Container;   
import java.awt.event.ActionEvent;   
import java.awt.event.ActionListener;   
import java.awt.event.WindowAdapter;   
import java.awt.event.WindowEvent;   
import java.io.Serializable;   
import java.util.Calendar;   
import java.util.Date;   
  
import javax.swing.BoxLayout;   
import javax.swing.JButton;   
import javax.swing.JFrame;   
import javax.swing.JLabel;   
import javax.swing.JPanel;   
import javax.swing.JTextArea;   
import javax.swing.JTextField;   
  
  
public class RunCommandPattern {   
    private static Calendar dateCreator = Calendar.getInstance();   
       
    public static void main(String [] arguments){   
        System.out.println("Example for the Command pattern");   
        System.out.println();   
        System.out.println("This sample will use a command class called");   
        System.out.println(" ChangeLocationCommand to update the location");   
        System.out.println(" of an Appointment object.");   
        System.out.println("The ChangeLocationCommand has the additional");   
        System.out.println(" ability to undo and redo commands, so it can");   
        System.out.println(" set the locaition back to its original value,");   
        System.out.println(" if desired.");   
        System.out.println();   
           
        System.out.println("Creating an Appointment for use in the demo");   
        Contact [] people = { new ContactImpl(), new ContactImpl() };   
        Appointment appointment = new Appointment("Java Twister Semi-Finals",   
            people, new LocationImpl(""), createDate(2001, 10, 31, 14, 30),   
            createDate(2001, 10, 31, 14, 31));   
           
        System.out.println("Creating the ChangeLocationCommand");   
        ChangeLocationCommand cmd = new ChangeLocationCommand();   
        cmd.setAppointment(appointment);   
           
        System.out.println("Creating the GUI");   
        CommandGui application = new CommandGui(cmd);   
        application.setAppointment(appointment);   
        cmd.setLocationEditor(application);   
        application.createGui();   
           
    }   
    public static Date createDate(int year, int month, int day, int hour, int minute){   
        dateCreator.set(year, month, day, hour, minute);   
        return dateCreator.getTime();   
    }   
}   
class CommandGui implements ActionListener, LocationEditor{   
    private JFrame mainFrame;   
    private JTextArea display;   
    private JTextField updatedLocation;   
    private JButton update, undo, redo, exit;   
    private JPanel controlPanel, displayPanel, editorPanel;   
    private UndoableCommand command;   
    private Appointment appointment;   
       
    public CommandGui(UndoableCommand newCommand){   
        command = newCommand;   
    }   
       
    public void setAppointment(Appointment newAppointment){   
        appointment = newAppointment;   
    }   
       
    public void createGui(){   
        mainFrame = new JFrame("Command Pattern Example");   
        Container content = mainFrame.getContentPane();   
        content.setLayout(new BoxLayout(content, BoxLayout.Y_AXIS));   
           
        editorPanel = new JPanel();   
        editorPanel.add(new JLabel("Location"));   
        updatedLocation = new JTextField(20);   
        editorPanel.add(updatedLocation);   
        content.add(editorPanel);   
           
        displayPanel = new JPanel();   
        display = new JTextArea(10, 40);   
        display.setEditable(false);   
        displayPanel.add(display);   
        content.add(displayPanel);   
           
        controlPanel = new JPanel();   
        update = new JButton("Update Location");   
        undo = new JButton("Undo Location");   
        redo = new JButton("Redo Location");   
        exit = new JButton("Exit");   
        controlPanel.add(update);   
        controlPanel.add(undo);   
        controlPanel.add(redo);   
        controlPanel.add(exit);   
        content.add(controlPanel);   
           
        update.addActionListener(this);   
        undo.addActionListener(this);   
        redo.addActionListener(this);   
        exit.addActionListener(this);   
           
        refreshDisplay();   
        mainFrame.addWindowListener(new WindowCloseManager());   
        mainFrame.pack();   
        mainFrame.setVisible(true);   
    }   
       
    public void actionPerformed(ActionEvent evt){   
        Object originator = evt.getSource();   
        if (originator == update){   
            executeCommand();   
        }   
        if (originator == undo){   
            undoCommand();   
        }   
        if (originator == redo){   
            redoCommand();   
        }   
        else if (originator == exit){   
            exitApplication();   
        }   
    }   
       
    private class WindowCloseManager extends WindowAdapter{   
        public void windowClosing(WindowEvent evt){   
            exitApplication();   
        }   
    }   
       
    public Location getNewLocation(){   
        return new LocationImpl(updatedLocation.getText());   
    }   
       
    private void executeCommand(){   
        command.execute();   
        refreshDisplay();   
    }   
       
    private void undoCommand(){   
        command.undo();   
        refreshDisplay();   
    }   
       
    private void redoCommand(){   
        command.redo();   
        refreshDisplay();   
    }   
       
    private void refreshDisplay(){   
        display.setText(appointment.toString());   
    }   
       
    private void exitApplication(){   
        System.exit(0);   
    }   
}   
interface Command{   
    public void execute();   
}   
interface Contact extends Serializable{   
    public static final String SPACE = " ";   
    public String getFirstName();   
    public String getLastName();   
    public String getTitle();   
    public String getOrganization();   
       
    public void setFirstName(String newFirstName);   
    public void setLastName(String newLastName);   
    public void setTitle(String newTitle);   
    public void setOrganization(String newOrganization);   
}   
  
class ContactImpl implements Contact{   
    private String firstName;   
    private String lastName;   
    private String title;   
    private String organization;   
    public static final String EOL_STRING =   
        System.getProperty("line.separator");   
       
    public ContactImpl(){ }   
    public ContactImpl(String newFirstName, String newLastName,   
        String newTitle, String newOrganization){   
            firstName = newFirstName;   
            lastName = newLastName;   
            title = newTitle;   
            organization = newOrganization;   
    }   
       
    public String getFirstName(){ return firstName; }   
    public String getLastName(){ return lastName; }   
    public String getTitle(){ return title; }   
    public String getOrganization(){ return organization; }   
       
    public void setFirstName(String newFirstName){ firstName = newFirstName; }   
    public void setLastName(String newLastName){ lastName = newLastName; }   
    public void setTitle(String newTitle){ title = newTitle; }   
    public void setOrganization(String newOrganization){ organization = newOrganization; }   
       
    public String toString(){   
        return firstName + " " + lastName;   
    }   
}   
  
class Appointment{   
    private String reason;   
    private Contact[] contacts;   
    private Location location;   
    private Date startDate;   
    private Date endDate;   
  
    public Appointment(String reason, Contact[] contacts, Location location, Date startDate, Date endDate){   
        this.reason = reason;   
        this.contacts = contacts;   
        this.location = location;   
        this.startDate = startDate;   
        this.endDate = endDate;   
    }   
       
    public String getReason(){ return reason; }   
    public Contact[] getContacts(){ return contacts; }   
    public Location getLocation(){ return location; }   
    public Date getStartDate(){ return startDate; }   
    public Date getEndDate(){ return endDate; }   
       
    public void setLocation(Location location){ this.location = location; }   
       
    public String toString(){   
        return "Appointment:" + "\n    Reason: " + reason +   
    "\n    Location: " + location + "\n    Start: " +   
            startDate + "\n    End: " + endDate + "\n";   
    }   
}   
  
interface Location extends Serializable{   
    public String getLocation();   
    public void setLocation(String newLocation);   
}   
  
class ChangeLocationCommand implements UndoableCommand{   
    private Appointment appointment;   
    private Location oldLocation;   
    private Location newLocation;   
    private LocationEditor editor;   
       
    public Appointment getAppointment(){ return appointment; }   
       
    public void setAppointment(Appointment appointment){ this.appointment = appointment; }   
    public void setLocationEditor(LocationEditor locationEditor){ editor = locationEditor; }   
       
    public void execute(){   
        oldLocation = appointment.getLocation();   
        newLocation = editor.getNewLocation();   
        appointment.setLocation(newLocation);   
    }   
    public void undo(){   
        appointment.setLocation(oldLocation);   
    }   
    public void redo(){   
        appointment.setLocation(newLocation);   
    }   
}   
  
interface LocationEditor{   
    public Location getNewLocation();   
}   
  
class LocationImpl implements Location{   
    private String location;   
       
    public LocationImpl(){ }   
    public LocationImpl(String newLocation){   
        location = newLocation;   
    }   
       
    public String getLocation(){ return location; }   
       
    public void setLocation(String newLocation){ location = newLocation; }   
       
    public String toString(){ return location; }   
}   
  
interface UndoableCommand extends Command{   
    public void undo();   
    public void redo();   
}