sclass SimpleCRUD<A extends Concept> {
  Class<A> cc;
  JTable table;
  JPanel buttons, panel;
  *(Class<A> *cc) {}
  
  SimpleCRUD<A> show() {
    make();
    showFrame(plural(shortClassName(cc)), panel);
    this;
  }
  
  JPanel make() {
    db();
    swing {
      table = makeConceptsTable(cc);
      panel = centerAndSouth(table, buttons = jRightAlignedLine(
        jbutton("Add...", r { newConcept() }),
        tableDependButton(table, jbutton("Edit", r {
          editConcept(selectedConcept())
        })),
        tableDependButton(table, jbutton("Delete", r {
          final A c = selectedConcept();
          withDBLock(r { c.delete() });
        }))));
      
      tablePopupMenuItem(table, "Edit...", voidfunc(int row) {
        editConcept((A) getConcept(toLong(getTableCell(table, row, 0))))
      });
    }
    ret panel;
  }
  
  void newConcept {
    final Map<S, JComponent> map = makeComponents(null);
    Runnable r = r { saveData(cnew(cc), map) };
    showFormTitled("New " + shortClassName(cc), arrayPlus(mapToObjectArray(map), r));
  }

  void editConcept(final A c) {
    if (c == null) ret;
    final Map<S, JComponent> map = makeComponents(c);
    Runnable r = r { saveData(c, map) };
    showFormTitled("Edit " + shortClassName(cc) + " #" + c.id, arrayPlus(mapToObjectArray(map), r));
  }
  
  A selectedConcept() {
    ret (A) getConcept(toLong(selectedTableCell(table, 0)));
  }
  
  Map<S, JComponent> makeComponents(A c) {
    Map<S, JComponent> map = litorderedmap();
    makeComponents(c, map);
    ret map;
  }
  
  // override the following two methods to customize edit window
  
  void makeComponents(A c, Map<S, JComponent> map) {
    for (S field : conceptFieldsInOrder(cc))
      map.put(field, jTextField(structureOrText_crud(getOpt(c, field))));
  }
  
  void saveData(A c, Map<S, JComponent> components) {
    for (S field : keys(components))
      if (components.get(field) instanceof JTextField)
        cset(c, field, convertToField(getTextTrim((JTextField) components.get(field)), cc, field));
  }
}