Add loading circle to JTable

Question

I have a JTable that loads data from a database. Because sometimes there's too much data, I would like to add a loading circle inside the Jtable to notify the user that the data is being loaded. Here is an image of how I would like it to be:

Is this possible? How can it be done in Swing?

PS: I don't want to use the progress bar, I just want the circle inside the table.

UPDATE: The table is part of the GUI and I only want to disable or show the loading inside the JTable and leave the other components intact.

Answer 1

Here's JLayer(Java 1.7.0) version, based on How to Decorate Components with the JLayer Class (The Java Tutorials > Creating a GUI With JFC/Swing > Using Other Swing Features)

import java.awt.*;
import java.awt.event.*;
import java.beans.PropertyChangeEvent;
import javax.swing.*;
import javax.swing.plaf.LayerUI;
import javax.swing.table.*;

public class TableWaitLayerTest {
  private final String[] columnNames = {"String", "Integer", "Boolean"};
  private final Object[][] data = {
    {"aaa", 12, true}, {"bbb", 5, false}, {"ccc", 9, false},
  };
  private final DefaultTableModel model = new DefaultTableModel(data, columnNames) {
    @Override public Class<?> getColumnClass(int column) {
      return getValueAt(0, column).getClass();
    }
  };
  private final JTable table = new JTable(model);
  private final JButton startButton = new JButton();
  private final WaitLayerUI layerUI = new WaitLayerUI();
  public JComponent makeUI() {
    startButton.setAction(new AbstractAction("start") {
      @Override public void actionPerformed(ActionEvent e) {
        layerUI.start();
        startButton.setEnabled(false);
        SwingWorker<String, Object[]> worker = new SwingWorker<String, Object[]>() {
          @Override public String doInBackground() {
            int current = 0, lengthOfTask = 120;
            while(current<lengthOfTask && !isCancelled()) {
              try {
                Thread.sleep(50);
              } catch(InterruptedException ie) {
                return "Interrupted";
              }
              publish(new Object[] {"aaa", current++, false});
            }
            return "Done";
          }
          @Override protected void process(java.util.List<Object[]> chunks) {
            for(Object[] array: chunks) {
              model.addRow(array);
            }
            table.scrollRectToVisible(
                table.getCellRect(model.getRowCount()-1, 0, true));
          }
          @Override public void done() {
            layerUI.stop();
            startButton.setEnabled(true);
            String text = null;
            if(isCancelled()) {
              text = "Cancelled";
            } else {
              try {
                text = get();
              } catch(Exception ex) {
                ex.printStackTrace();
                text = "Exception";
              }
            }
          }
        };
        worker.execute();
      }
    });
    JPanel p = new JPanel(new BorderLayout());
    p.add(new JButton("dummy"), BorderLayout.NORTH);
    p.add(new JLayer<JComponent>(new JScrollPane(table), layerUI));
    p.add(startButton, BorderLayout.SOUTH);
    return p;
  }
  public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
      @Override public void run() {
        createAndShowGUI();
      }
    });
  }
  public static void createAndShowGUI() {
    JFrame f = new JFrame();
    f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    f.getContentPane().add(new TableWaitLayerTest().makeUI());
    f.setSize(320, 240);
    f.setLocationRelativeTo(null);
    f.setVisible(true);
  }
}

//http://docs.oracle.com/javase/tutorial/uiswing/misc/jlayer.html
//How to Decorate Components with the JLayer Class
//(The Java? Tutorials > Creating a GUI With JFC/Swing > Using Other Swing Features)
//TapTapTap.java
class WaitLayerUI extends LayerUI<JComponent> implements ActionListener {
  private boolean mIsRunning;
  private boolean mIsFadingOut;
  private Timer mTimer;

  private int mAngle;
  private int mFadeCount;
  private int mFadeLimit = 15;

  @Override public void paint (Graphics g, JComponent c) {
    int w = c.getWidth();
    int h = c.getHeight();

    // Paint the view.
    super.paint (g, c);

    if (!mIsRunning) {
      return;
    }

    Graphics2D g2 = (Graphics2D)g.create();

    float fade = (float)mFadeCount / (float)mFadeLimit;
    // Gray it out.
    Composite urComposite = g2.getComposite();
    g2.setComposite(AlphaComposite.getInstance(
                      AlphaComposite.SRC_OVER, .5f * fade));
    g2.fillRect(0, 0, w, h);
    g2.setComposite(urComposite);

    // Paint the wait indicator.
    int s = Math.min(w, h) / 5;
    int cx = w / 2;
    int cy = h / 2;
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                        RenderingHints.VALUE_ANTIALIAS_ON);
    g2.setStroke(
      new BasicStroke(s / 4, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND));
    g2.setPaint(Color.white);
    g2.rotate(Math.PI * mAngle / 180, cx, cy);
    for (int i = 0; i < 12; i++) {
      float scale = (11.0f - (float)i) / 11.0f;
      g2.drawLine(cx + s, cy, cx + s * 2, cy);
      g2.rotate(-Math.PI / 6, cx, cy);
      g2.setComposite(AlphaComposite.getInstance(
                        AlphaComposite.SRC_OVER, scale * fade));
    }

    g2.dispose();
  }

  @Override public void actionPerformed(ActionEvent e) {
    if (mIsRunning) {
      firePropertyChange("tick", 0, 1);
      mAngle += 3;
      if (mAngle >= 360) {
        mAngle = 0;
      }
      if (mIsFadingOut) {
        if (--mFadeCount == 0) {
          mIsRunning = false;
          mTimer.stop();
        }
      } else if (mFadeCount < mFadeLimit) {
        mFadeCount++;
      }
    }
  }

  public void start() {
    if (mIsRunning) {
      return;
    }
    // Run a thread for animation.
    mIsRunning = true;
    mIsFadingOut = false;
    mFadeCount = 0;
    int fps = 24;
    int tick = 1000 / fps;
    mTimer = new Timer(tick, this);
    mTimer.start();
  }

  public void stop() {
    mIsFadingOut = true;
  }

  @Override public void applyPropertyChange(PropertyChangeEvent pce, JLayer l) {
    if ("tick".equals(pce.getPropertyName())) {
      l.repaint();
    }
  }

  @Override public void installUI(JComponent c) {
    super.installUI(c);
    ((JLayer)c).setLayerEventMask(
      AWTEvent.MOUSE_EVENT_MASK | AWTEvent.MOUSE_MOTION_EVENT_MASK |
      AWTEvent.MOUSE_WHEEL_EVENT_MASK | AWTEvent.KEY_EVENT_MASK |
      AWTEvent.FOCUS_EVENT_MASK | AWTEvent.COMPONENT_EVENT_MASK);
  }
  @Override public void uninstallUI(JComponent c) {
    ((JLayer)c).setLayerEventMask(0);
    super.uninstallUI(c);
  }
  @Override public void eventDispatched(AWTEvent e, JLayer<? extends JComponent> l) {
    if(mIsRunning && e instanceof InputEvent) {
      ((InputEvent)e).consume();
    }
  }
}