import javax.swing.undo.UndoManager;

static <A extends JTextComponent> A jenableUndoRedo(A textcomp) {
  swing {
    new UndoManager undo;
    vm_generalWeakSet("Undo Managers").add(undo);
    setMeta(textcomp, "UndoManager", undo);
    textcomp.getDocument().addUndoableEditListener(new UndoableEditListener() {
      public void undoableEditHappened(UndoableEditEvent evt) {
        undo.addEdit(evt.getEdit());
      }
    });
    
    textcomp.getActionMap().put("Undo", abstractAction("Undo", r {
      if (undo.canUndo()) undo.undo()
    }));
    textcomp.getActionMap().put("Redo", abstractAction("Redo", r {
      if (undo.canRedo()) undo.redo()
    }));
    textcomp.getInputMap().put(KeyStroke.getKeyStroke("control Z"), "Undo");
    textcomp.getInputMap().put(KeyStroke.getKeyStroke("control Y"), "Redo");
  }
  ret textcomp;
}