supprimer un Runnable de ScheduledExecutorService

Question

Voici la situation, le code est ci-dessous

utilisateur remplit 3 champs et appuyez sur la bouton « Ajouter » => une ToDoBean est créée et ajoutée à un ToDoModel (étend AbstractTableModel) et un Runnable est créé avec l'index de ToDoBean dans le modèle. Le Runnable est démarré immédiatement via un ScheduledExecutorService.

Le but de Runnable est de décrémenter un int jusqu'à ce qu'il atteigne zéro.

Tout fonctionne bien.

Maintenant, l'utilisateur peut également sélectionner une ligne dans la JTable et appuyez sur le bouton "Supprimer" pour supprimer le ToDoBean de la liste.

Ma question est la suivante: lorsque je supprime le bean, il semble qu'il soit également supprimé du ScheduledExecutorService. Pourquoi? Comment? En fait, c'est exactement ce dont j'ai besoin, mais je voudrais comprendre les mécanismes. Merci

Le code:

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 
} 

package demo.todolist;

import java.util.ArrayList; import java.util.List; import javax.swing.table.AbstractTableModel;

ToDoModel public class étend 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; 
} } 

package demo.todolist;

ToDoBean public class {

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--; 
} } 

Answer 1

je suis tombé sur votre question et j'ai une belle solution. Utilisez un ScheduledThreadPoolExecutor. Il vous permettra de planifier des tâches et aussi de les supprimer quand elles ne sont plus nécessaires.