employeemanager.java~7~

来自「《深入浅出设计模式》的完整源代码」· JAVA~7~ 代码 · 共 121 行

package program;

import employee.Employee;
import employee.EmployeeMemento;
import javax.swing.*;
import javax.swing.undo.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;

public class EmployeeManager{
  private JButton loadButton = new JButton("Load");
  private JButton saveButton = new JButton("Save");
  private JButton undoSaveButton = new JButton("Undo Save");
  private JTextField idText = new JTextField();;
  private JTextField firstNameText = new JTextField();;
  private JTextField lastNameText = new JTextField();;
  private JTextField salaryText = new JTextField();;
  private JFrame frame;
  private Vector employees;
  private UndoManager um;


  // here is the employee object we will be working with
  private Employee employee = new Employee();


  public static void main(String[] args){
      new EmployeeManager();
  }

  EmployeeManager(){
    frame = new JFrame("Memento Pattern Example");
    um=new UndoManager();
    employees=new Vector();
    frame.addWindowListener(new WindowAdapter() {
      public void windowClosing(WindowEvent e) {
        System.exit(0);
      }
    });

    // create input field panel
    JPanel topPanel = new JPanel();
    topPanel.setLayout(new GridLayout(4,2));
    topPanel.add(new JLabel("ID:"));
    topPanel.add(idText);
    topPanel.add(new JLabel("First Name:"));
    topPanel.add(firstNameText);
    topPanel.add(new JLabel("Last Name:"));
    topPanel.add(lastNameText);
    topPanel.add(new JLabel("Salary:"));
    topPanel.add(salaryText);

    // create button panel
    JPanel bottomPanel = new JPanel();
    bottomPanel.setLayout(new FlowLayout());
    bottomPanel.add(loadButton);
    bottomPanel.add(saveButton);
    bottomPanel.add(undoSaveButton);

    // set the action listeners to each button
    loadButton.addActionListener(new ActionListener(){
      public void actionPerformed(ActionEvent e){
        loadEmployee();
      }
    });
    saveButton.addActionListener(new ActionListener(){
      public void actionPerformed(ActionEvent e){
        saveEmployee();
      }
    });
    undoSaveButton.addActionListener(new ActionListener(){
      public void actionPerformed(ActionEvent e){
        undoEmployee();
      }
    });

    // add the panels to the frame and show it
    frame.getContentPane().setLayout(new BorderLayout());
    frame.getContentPane().add(topPanel, BorderLayout.CENTER);
    frame.getContentPane().add(bottomPanel, BorderLayout.SOUTH);
    frame.pack();
    frame.setVisible(true);

    // display the employee for the first time
    loadEmployee();
  }

  private void loadEmployee(){
    idText.setText(""+employee.getId());
    firstNameText.setText(employee.getFirstName());
    lastNameText.setText(employee.getLastName());
    salaryText.setText(""+employee.getSalary());
  }

  private void saveEmployee(){
    EmployeeMemento memento;

    employee.setId(Integer.parseInt(idText.getText()));
    employee.setFirstName(firstNameText.getText());
    employee.setLastName(lastNameText.getText());
    employee.setSalary(Integer.parseInt(salaryText.getText()));
    memento = employee.getMemento();
    employees.addElement(memento);

  }

  private void undoEmployee(){
    /*
    if(memento==null){
      JOptionPane.showMessageDialog(frame, "No memento saved yet.",
        "Error", JOptionPane.ERROR_MESSAGE);
    }*/
    EmployeeMemento memento;
    memento=(EmployeeMemento)employees.lastElement();
    employee.setMemento(memento);
    employees.removeElement(memento);
    loadEmployee();
  }
}