praktikum-holons/src/holeg/ui/view/component/ButtonTabComponent.java

package holeg.ui.view.component;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.AbstractButton;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTabbedPane;
import javax.swing.plaf.basic.BasicButtonUI;

/**
 * Component to be used as tabComponent; Contains a JLabel to show the text and a JButton to close
 * the tab it belongs to
 */
public class ButtonTabComponent extends JPanel {

  private final static MouseListener buttonMouseListener = new MouseAdapter() {
    public void mouseEntered(MouseEvent e) {
      Component component = e.getComponent();
      if (component instanceof AbstractButton button) {
        button.setBorderPainted(true);
      }
    }

    public void mouseExited(MouseEvent e) {
      Component component = e.getComponent();
      if (component instanceof AbstractButton button) {
        button.setBorderPainted(false);
      }
    }
  };
  private final JTabbedPane pane;

  public ButtonTabComponent(final JTabbedPane pane) {
    // unset default FlowLayout' gaps
    super(new FlowLayout(FlowLayout.LEFT, 0, 0));
    if (pane == null) {
      throw new NullPointerException("TabbedPane is null");
    }
    this.pane = pane;
    setOpaque(false);

    // make JLabel read titles from JTabbedPane
    JLabel label = new JLabel() {
      public String getText() {
        int i = pane.indexOfTabComponent(ButtonTabComponent.this);
        if (i != -1) {
          return pane.getTitleAt(i);
        }
        return null;
      }
    };

    add(label);
    // add more space between the label and the button
    label.setBorder(BorderFactory.createEmptyBorder(0, 0, 0, 5));
    // tab button
    JButton button = new TabButton();
    add(button);
    // add more space to the top of the component
    setBorder(BorderFactory.createEmptyBorder(2, 0, 0, 0));
  }

  /**
   * removes both Tabs
   */
  public void removeTabs() {
    int i = pane.indexOfTabComponent(ButtonTabComponent.this);
    if (i != -1) {
      pane.remove(i);
    }
  }

  private class TabButton extends JButton implements ActionListener {

    public TabButton() {
      int size = 17;
      setPreferredSize(new Dimension(size, size));
      setToolTipText("close this tab");
      // Make the button looks the same for all Laf's
      setUI(new BasicButtonUI());
      // Make it transparent
      setContentAreaFilled(false);
      // No need to be focusable
      setFocusable(false);
      setBorder(BorderFactory.createEtchedBorder());
      setBorderPainted(false);
      // Making nice rollover effect
      // we use the same listener for all buttons
      addMouseListener(buttonMouseListener);
      setRolloverEnabled(true);
      // Close the proper tab by clicking the button
      addActionListener(this);
    }

    public void actionPerformed(ActionEvent e) {
      removeTabs();
    }

    // we don't want to update UI for this button
    public void updateUI() {
    }

    // paint the cross
    protected void paintComponent(Graphics g) {
      super.paintComponent(g);
      Graphics2D g2 = (Graphics2D) g.create();
      // shift the image for pressed buttons
      if (getModel().isPressed()) {
        g2.translate(1, 1);
      }
      g2.setStroke(new BasicStroke(2));
      g2.setColor(Color.BLACK);
      if (getModel().isRollover()) {
        g2.setColor(Color.MAGENTA);
      }
      int delta = 6;
      g2.drawLine(delta, delta, getWidth() - delta - 1, getHeight() - delta - 1);
      g2.drawLine(getWidth() - delta - 1, delta, delta, getHeight() - delta - 1);
      g2.dispose();
    }
  }
}