protected Column(final Column entityToCopy) {

      super(entityToCopy);

      myActivator = entityToCopy.needsActivator();
      myInteger = entityToCopy.isInteger();

      myElements.putAll(entityToCopy.myElements);
    }
  /**
   * @see #getActivatorVariableColumns()
   * @see #getNegativeVariableColumns()
   * @see #getPositiveVariableColumns()
   */
  public Column[] getActivatorVariableColumns() {

    final HashSet<Column> tmpSelection = new HashSet<Column>();

    for (final Column tmpColumn : myColumns.values()) {
      if (tmpColumn.needsActivator()) {
        tmpSelection.add(tmpColumn);
      }
    }

    return tmpSelection.toArray(new Column[tmpSelection.size()]);
  }