JList with Thread

[Kuba Jakub]

Hi,

I try to code GUI with JList which will contain thread pool and four buttons, three buttons for launch new task and one button to cancel selected task.
For start I can define the number of running thread (newScheduledThreadPool())
The active thread should have different background color (in Jlist) compare to recumbent task.
Task1, Task2, Task3 should work with different peridoicaly(scheduleAtFixedRate())

Can you help me what shoud I use to click on button(1-3) and add new task to thread pool and how to cancel the task vi select in Jlist and clik button cancel?

What I have is:

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.concurrent.*;

import javax.swing.DefaultListCellRenderer;
import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.ListCellRenderer;
import javax.swing.ListModel;
import javax.swing.ListSelectionModel;
import javax.swing.event.AncestorEvent;
import javax.swing.event.AncestorListener;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;

class Task implements Runnable{
	
	public String taskName;
	public int time;
	
	public Task(String name,int time)
	{
		taskName = name;
		this.time = time;
	}
	public void run() {
			try {
				System.out.println(taskName);
				Thread.sleep(time);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}			
	}
	public String toString()
	{
		return taskName;
	}

}

public class ObslugaWatkow {

	JFrame frame; 
	JPanel panel;
	JButton button1,button2,button3,button4;
	JList lista;
	JScrollPane listScroller;
	DefaultListModel listaModel;
	
	
	public ObslugaWatkow()
	{		
		listaModel = new DefaultListModel();
		lista = new JList(listaModel);
		lista.setCellRenderer(new MyCellRenderer());
		
		final ScheduledExecutorService exec  = Executors.newScheduledThreadPool(3);
				
		frame = new JFrame("UTP - Tasks executor");
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		button1 = new JButton("Task 1");
		button2 = new JButton("Task 2");
		button3 = new JButton("Task 3");
		button4 = new JButton("Delete");
		button4.setEnabled(false);
		button1.addActionListener(new ActionListener() {
			
			@Override
			public void actionPerformed(ActionEvent e) {
				Task tmp = new Task("Task 1",5000);
				ScheduledFuture task = exec.scheduleAtFixedRate(tmp,0, 5, TimeUnit.SECONDS);
				listaModel.addElement(tmp);				
				lista.updateUI();	
				
				
			}
		});
		button2.addActionListener(new ActionListener() {
			
			@Override
			public void actionPerformed(ActionEvent e) {
				Task tmp = new Task("Task 2",10000);
				ScheduledFuture task = exec.scheduleAtFixedRate(tmp,0, 10, TimeUnit.SECONDS);
				listaModel.addElement(tmp);				
				lista.updateUI();	
			}
		});
		button3.addActionListener(new ActionListener() {
			
			@Override
			public void actionPerformed(ActionEvent e) {
				Task tmp = new Task("Task 3",15000);
				ScheduledFuture task = exec.scheduleAtFixedRate(tmp,0, 15, TimeUnit.SECONDS);
				listaModel.addElement(tmp);			
				lista.updateUI();	
			}
		});
		button4.addActionListener(new ActionListener() {
			
			@Override
			public void actionPerformed(ActionEvent e) {
				int index = lista.getSelectedIndex();
			    listaModel.remove(index);

			    int size = listaModel.getSize();

			    if (size == 0) {
			        button4.setEnabled(false);
			        panel.requestFocus();
			    } else {
			        if (index == listaModel.getSize()) {
			            index--;
			        }
			        lista.setSelectedIndex(index);
			        button4.requestFocus();
			    }	
			    Toolkit.getDefaultToolkit().beep();
			}
		});
		
		panel = new JPanel(new FlowLayout());
		panel.add(button1);
		panel.add(button2);
		panel.add(button3);
				
		lista.setLayoutOrientation(JList.VERTICAL);
		lista.setVisibleRowCount(-1);
		lista.setSelectionMode(ListSelectionModel.SINGLE_SELECTION );
		lista.addListSelectionListener(new ListSelectionListener() {			
			@Override
			public void valueChanged(ListSelectionEvent e) {
				if (e.getValueIsAdjusting() == false) {
			        if (lista.getSelectedIndex() == -1) {
			            button4.setEnabled(false);
			        } else {
			            button4.setEnabled(true);
			        }
			    }	
			}
		});
		listScroller = new JScrollPane(lista);
		listScroller.setPreferredSize(new Dimension(250,250));
		
		frame.getContentPane().add(panel,BorderLayout.PAGE_START);
		frame.getContentPane().add(listScroller,BorderLayout.CENTER);
		frame.getContentPane().add(button4,BorderLayout.PAGE_END);
		
		frame.setSize(300,250);
		frame.setResizable(false);
		frame.setVisible(true);
		
			
	}
	
	public static void main(String[] args) {
		new ObslugaWatkow();
		
	}

}
class MyCellRenderer extends JLabel implements ListCellRenderer {
    public MyCellRenderer() {
        setOpaque(true);
    }

    public Component getListCellRendererComponent(JList list,
                                                  Object value,
                                                  int index,
                                                  boolean isSelected,
                                                  boolean cellHasFocus) {

        Color background;
        Color foreground;

        // check if this cell represents the current DnD drop location
        JList.DropLocation dropLocation = list.getDropLocation();
        if (dropLocation != null
                && !dropLocation.isInsert()
                && dropLocation.getIndex() == index) {

            background = Color.BLUE;
            foreground = Color.WHITE;

        // check if this cell is selected
        } else if (isSelected) {
            background = Color.RED;
            foreground = Color.WHITE;

        // unselected, and not the DnD drop location
        } else {
            background = Color.WHITE;
            foreground = Color.BLACK;
        }
        
        setBackground(background);
        setForeground(foreground);

        return this;
    }
}