DefaultContextMenu.java

/**
 *  
 */
package org.jmeld.ui;

  import java.awt.Toolkit;
  import java.awt.datatransfer.Clipboard;
  import java.awt.datatransfer.DataFlavor;
  import java.awt.event.ActionEvent;
  import java.awt.event.ActionListener;
  import java.awt.event.KeyAdapter;
  import java.awt.event.KeyEvent;
  import java.awt.event.MouseAdapter;
  import java.awt.event.MouseEvent;

  import javax.swing.JMenuItem;
  import javax.swing.JPopupMenu;
  import javax.swing.JSeparator;
  import javax.swing.KeyStroke;
  import javax.swing.event.UndoableEditEvent;
  import javax.swing.event.UndoableEditListener;
  import javax.swing.text.JTextComponent;
  import javax.swing.undo.UndoManager;

  /**
	 * Helper class see http://stackoverflow.com/a/28283704/1497139
	 */
  @SuppressWarnings("serial")
  public class DefaultContextMenu extends JPopupMenu
  {
      private Clipboard clipboard;

      private UndoManager undoManager;

      private JMenuItem undo;
      private JMenuItem redo;
      private JMenuItem cut;
      private JMenuItem copy;
      private JMenuItem paste;
      private JMenuItem delete;
      private JMenuItem selectAll;

      private JTextComponent jTextComponent;

      public DefaultContextMenu()
      {
          undoManager = new UndoManager();
          clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();

          undo = new JMenuItem("Undo");
          undo.setEnabled(false);
          undo.setAccelerator(KeyStroke.getKeyStroke("control Z"));
          undo.addActionListener(new ActionListener()
          {
              public void actionPerformed(ActionEvent event)
              {
                  undoManager.undo();
              }
          });

          add(undo);

          redo = new JMenuItem("Redo");
          redo.setEnabled(false);
          redo.setAccelerator(KeyStroke.getKeyStroke("control Y"));
          redo.addActionListener(new ActionListener()
          {
              public void actionPerformed(ActionEvent event)
              {
                  undoManager.redo();
              }
          });

          add(redo);

          add(new JSeparator());

          cut = new JMenuItem("Cut");
          cut.setEnabled(false);
          cut.setAccelerator(KeyStroke.getKeyStroke("control X"));
          cut.addActionListener(new ActionListener()
          {
              public void actionPerformed(ActionEvent event)
              {
                  jTextComponent.cut();
              }
          });

          add(cut);

          copy = new JMenuItem("Copy");
          copy.setEnabled(false);
          copy.setAccelerator(KeyStroke.getKeyStroke("control C"));
          copy.addActionListener(new ActionListener()
          {
              public void actionPerformed(ActionEvent event)
              {
                  jTextComponent.copy();
              }
          });

          add(copy);

          paste = new JMenuItem("Paste");
          paste.setEnabled(false);
          paste.setAccelerator(KeyStroke.getKeyStroke("control V"));
          paste.addActionListener(new ActionListener()
          {
              public void actionPerformed(ActionEvent event)
              {
                  jTextComponent.paste();
              }
          });

          add(paste);

          delete = new JMenuItem("Delete");
          delete.setEnabled(false);
          delete.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_DELETE, 0));
          delete.addActionListener(new ActionListener()
          {
              public void actionPerformed(ActionEvent event)
              {
                  jTextComponent.replaceSelection("");
              }
          });

          add(delete);

          add(new JSeparator());

          selectAll = new JMenuItem("Select All");
          selectAll.setEnabled(false);
          selectAll.setAccelerator(KeyStroke.getKeyStroke("control A"));
          selectAll.addActionListener(new ActionListener()
          {
              public void actionPerformed(ActionEvent event)
              {
                  jTextComponent.selectAll();
              }
          });

          add(selectAll);
      }

      public void add(JTextComponent jTextComponent)
      {
          jTextComponent.addKeyListener(new KeyAdapter()
          {
              @Override
              public void keyPressed(KeyEvent pressedEvent)
              {
                  if ((pressedEvent.getKeyCode() == KeyEvent.VK_Z)
                          && ((pressedEvent.getModifiers() & KeyEvent.CTRL_MASK) != 0))
                  {
                      if (undoManager.canUndo())
                      {
                          undoManager.undo();
                      }
                  }

                  if ((pressedEvent.getKeyCode() == KeyEvent.VK_Y)
                          && ((pressedEvent.getModifiers() & KeyEvent.CTRL_MASK) != 0))
                  {
                      if (undoManager.canRedo())
                      {
                          undoManager.redo();
                      }
                  }
              }
          });

          jTextComponent.addMouseListener(new MouseAdapter()
          {
              @Override
              public void mouseReleased(MouseEvent releasedEvent)
              {
                  if (releasedEvent.getButton() == MouseEvent.BUTTON3)
                  {
                      processClick(releasedEvent);
                  }
              }
          });

          jTextComponent.getDocument().addUndoableEditListener(
                  new UndoableEditListener()
                  {
                      @Override
                      public void undoableEditHappened(UndoableEditEvent event)
                      {
                          undoManager.addEdit(event.getEdit());
                      }
                  });
      }

      private void processClick(MouseEvent event)
      {
          jTextComponent = (JTextComponent) event.getSource();

          boolean enableUndo = undoManager.canUndo();
          boolean enableRedo = undoManager.canRedo();
          boolean enableCut = false;
          boolean enableCopy = false;
          boolean enablePaste = false;
          boolean enableDelete = false;
          boolean enableSelectAll = false;

          String selectedText = jTextComponent.getSelectedText();
          String text = jTextComponent.getText();

          if (text != null)
          {
              if (text.length() > 0)
              {
                  enableSelectAll = true;
              }
          }

          if (selectedText != null)
          {
              if (selectedText.length() > 0)
              {
                  enableCut = true;
                  enableCopy = true;
                  enableDelete = true;
              }
          }

          try
          {
              if (clipboard.getData(DataFlavor.stringFlavor) != null)
              {
                  enablePaste = true;
              }
          } catch (Exception exception)
          {
              exception.printStackTrace();
          }

          undo.setEnabled(enableUndo);
          redo.setEnabled(enableRedo);
          cut.setEnabled(enableCut);
          copy.setEnabled(enableCopy);
          paste.setEnabled(enablePaste);
          delete.setEnabled(enableDelete);
          selectAll.setEnabled(enableSelectAll);

          show(jTextComponent, event.getX(), event.getY());
      }
  }