情况是这样的，代码如下
用户填写 3 个字段并按“添加”按钮
=> 创建一个 ToDoBean 并将其添加到 ToDoModel（扩展 AbstractTableModel）
并使用模型中 ToDoBean 的索引创建一个 Runnable。
Runnable 通过 ScheduledExecutorService 立即启动。
Runnable 的目标是递减 int 直到它达到零。
一切正常。
现在用户还可以在 JTable 中选择一行并按“Remove”按钮从列表中删除 ToDoBean。
我的问题是：当我删除该 bean 时，它看起来也从 ScheduledExecutorService 中删除了。为什么？如何？
事实上，这正是我所需要的，但我想了解其机制。
谢谢
代码：
package demo.todolist;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.WindowConstants;
public class ToDoFrame extends javax.swing.JFrame {
private final static int POOL_SIZE = 10;
private ToDoModel model = new ToDoModel();
private ScheduledExecutorService scheduledExecutorService = Executors.newScheduledThreadPool(POOL_SIZE);
/** Creates new form ToDoFrame */
public ToDoFrame() {
initComponents();
}
private ToDoBean createToDoBean() {
return new ToDoBean(jTextField1.getText(), jTextField2.getText(), Long.valueOf(jTextField3.getText()));
}
private void addToList(ToDoBean toDoBean) {
model.addToDoBean(toDoBean);
scheduledExecutorService.schedule(new UpdateRunnable(model.getRowCount() - 1), 0,TimeUnit.SECONDS);
}
private class UpdateRunnable implements Runnable {
private int index;
public UpdateRunnable(int index) {
this.index = index;
}
@Override
public void run() {
System.out.println("Task for index " + index + " started");
while (model.getToDoBeanAt(index).getDelay() > 0) {
try {
Thread.sleep(10000);
model.decreaseBeanAt(index);
System.out.println("Delay decreased at index " + index);
} catch (InterruptedException ex) {
Logger.getLogger(ToDoFrame.class.getName()).log(Level.SEVERE, null, ex);
}
}
System.out.println("Task for index " + index + " ended");
}
}
/** This method is called from within the constructor to
* initialize the form.
* WARNING: Do NOT modify this code. The content of this method is
* always regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
GridBagConstraints gridBagConstraints;
jLabel1 = new JLabel();
jLabel2 = new JLabel();
jLabel3 = new JLabel();
jTextField1 = new JTextField();
jTextField2 = new JTextField();
jTextField3 = new JTextField();
jButton1 = new JButton();
jScrollPane1 = new JScrollPane();
jTable1 = new JTable();
jButton2 = new JButton();
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
getContentPane().setLayout(new GridBagLayout());
jLabel1.setText("Name :");
gridBagConstraints = new GridBagConstraints();
gridBagConstraints.anchor = GridBagConstraints.LINE_END;
gridBagConstraints.insets = new Insets(5, 5, 5, 5);
getContentPane().add(jLabel1, gridBagConstraints);
jLabel2.setText("Description :");
gridBagConstraints = new GridBagConstraints();
gridBagConstraints.gridx = 0;
gridBagConstraints.gridy = 1;
gridBagConstraints.anchor = GridBagConstraints.LINE_END;
gridBagConstraints.insets = new Insets(5, 5, 5, 5);
getContentPane().add(jLabel2, gridBagConstraints);
jLabel3.setText("Delai (seconds) :");
gridBagConstraints = new GridBagConstraints();
gridBagConstraints.gridx = 0;
gridBagConstraints.gridy = 2;
gridBagConstraints.anchor = GridBagConstraints.LINE_END;
gridBagConstraints.insets = new Insets(5, 5, 5, 5);
getContentPane().add(jLabel3, gridBagConstraints);
jTextField1.setText("my name ");
jTextField1.setMinimumSize(new Dimension(50, 25));
jTextField1.setPreferredSize(new Dimension(80, 27));
gridBagConstraints = new GridBagConstraints();
gridBagConstraints.anchor = GridBagConstraints.LINE_START;
gridBagConstraints.insets = new Insets(5, 5, 5, 5);
getContentPane().add(jTextField1, gridBagConstraints);
jTextField2.setText("some description");
jTextField2.setMinimumSize(new Dimension(145, 25));
jTextField2.setPreferredSize(new Dimension(145, 27));
gridBagConstraints = new GridBagConstraints();
gridBagConstraints.gridx = 1;
gridBagConstraints.gridy = 1;
gridBagConstraints.gridwidth = 2;
gridBagConstraints.anchor = GridBagConstraints.LINE_START;
gridBagConstraints.insets = new Insets(5, 5, 5, 5);
getContentPane().add(jTextField2, gridBagConstraints);
jTextField3.setHorizontalAlignment(JTextField.TRAILING);
jTextField3.setText("5");
jTextField3.setMinimumSize(new Dimension(25, 25));
jTextField3.setPreferredSize(new Dimension(25, 27));
gridBagConstraints = new GridBagConstraints();
gridBagConstraints.gridx = 1;
gridBagConstraints.gridy = 2;
gridBagConstraints.anchor = GridBagConstraints.LINE_START;
gridBagConstraints.insets = new Insets(5, 5, 5, 5);
getContentPane().add(jTextField3, gridBagConstraints);
jButton1.setText("Add");
jButton1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
getContentPane().add(jButton1, new GridBagConstraints());
jScrollPane1.setMinimumSize(new Dimension(280, 150));
jScrollPane1.setPreferredSize(new Dimension(280, 275));
jTable1.setModel(model
);
jScrollPane1.setViewportView(jTable1);
gridBagConstraints = new GridBagConstraints();
gridBagConstraints.gridx = 0;
gridBagConstraints.gridy = 3;
gridBagConstraints.gridwidth = 3;
getContentPane().add(jScrollPane1, gridBagConstraints);
jButton2.setText("Remove");
jButton2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
jButton2ActionPerformed(evt);
}
});
gridBagConstraints = new GridBagConstraints();
gridBagConstraints.gridx = 2;
gridBagConstraints.gridy = 2;
gridBagConstraints.insets = new Insets(5, 5, 5, 5);
getContentPane().add(jButton2, gridBagConstraints);
pack();
}// </editor-fold>
private void jButton1ActionPerformed(ActionEvent evt) {
addToList(createToDoBean());
}
private void jButton2ActionPerformed(ActionEvent evt) {
int rowIndex = jTable1.getSelectedRow();
model.removeToDoBeanAt(rowIndex);
/*
* the ToDoBean is removed from the list
* the table is updated
* the scheduledExecutorService is also updated ... why?
*/
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(ToDoFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(ToDoFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(ToDoFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(ToDoFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
new ToDoFrame().setVisible(true);
}
});
}
// Variables declaration - do not modify
private JButton jButton1;
private JButton jButton2;
private JLabel jLabel1;
private JLabel jLabel2;
private JLabel jLabel3;
private JScrollPane jScrollPane1;
private JTable jTable1;
private JTextField jTextField1;
private JTextField jTextField2;
private JTextField jTextField3;
// End of variables declaration
}
包 demo.todolist；
导入java.util.ArrayList；导入java.util.List；进口
javax.swing.table.AbstractTableModel;
公共类 ToDoModel 扩展 AbstractTableModel {
protected List<ToDoBean> list = new ArrayList<ToDoBean>();
private final static String[] columns = {"Name", "Description", "Remaining"};
private final static Class[] columnsClass = {String.class, String.class, Long.class};
public final static int[] columnWidths = {80, 150, 50}; // 280
public ToDoModel() {
}
public ToDoModel(List<ToDoBean> list) {
super();
this.list = list;
}
@Override
public Class getColumnClass(int columnIndex) {
return columnsClass[columnIndex];
}
@Override
public int getRowCount() {
return list.size();
}
@Override
public int getColumnCount() {
return columns.length;
}
@Override
public String getColumnName(int col) {
return columns[col];
}
@Override
public boolean isCellEditable(int rowIndex, int columnIndex) {
return false;
}
@Override
public Object getValueAt(int rowIndex, int columnIndex) {
ToDoBean result = list.get(rowIndex);
switch (columnIndex) {
case 0:
return result.getName();
case 1:
return result.getDescription();
default:
return result.getDelay();
}
}
@Override
public void setValueAt(Object obj,int rowIndex, int columnIndex) {
ToDoBean result = list.get(rowIndex);
switch (columnIndex) {
case 0:
result.setName((String) obj);
break;
case 1:
result.setDescription((String) obj);
break;
default:
result.setDelay((Long) obj);
}
list.set(rowIndex, result);
this.fireTableCellUpdated(rowIndex, columnIndex);
}
public void addToDoBean(ToDoBean w) {
list.add(w);
fireTableDataChanged();
}
public void addToDoBeanList(List l) {
list.addAll(l);
fireTableDataChanged();
}
public ToDoBean getToDoBeanAt(int row) {
return list.get(row);
}
public ToDoBean removeToDoBeanAt(int row) {
ToDoBean pos = list.remove(row);
fireTableDataChanged();
return pos;
}
public long decreaseBeanAt(int rowIndex) {
ToDoBean result = list.get(rowIndex);
long remaining = result.getDelay();
result.setDelay(--remaining);
this.fireTableCellUpdated(rowIndex, 2);
return remaining;
} }
包 demo.todolist；
公共类 ToDoBean {
private String name;
private String description;
private long delay;
public ToDoBean(String name, String description, long delay) {
this.name = name;
this.description = description;
this.delay = delay;
}
public ToDoBean() {
}
public long getDelay() {
return delay;
}
public void setDelay(long delay) {
this.delay = delay;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public void decrease() {
delay--;
} }
