/**
   * Updates all coordinates
   *
   * @todo Optimise. Some info can be cached
   * @todo Handle m:n (leftY/rightY etc)
   */
  public void update() {
    /*
     *  int leftY = _leftTable.getY() + _leftTable.getColumnY(_leftRole.getColumnMap().getPrimaryKey());
     *  int rightY;
     *  if (!_leftRole.getRelation().isMany2Many()) {
     *  rightY = _rightTable.getY() + _rightTable.getColumnY(_leftRole.getColumnMap().getForeignKey());
     *  }
     *  else {
     *  rightY = _rightTable.getY() + _rightTable.getColumnY(_rightRole.getColumnMap().getPrimaryKey());
     *  }
     */
    int leftY = _leftTable.getY() + _leftColumnY;
    int rightY = _rightTable.getY() + _rightColumnY;

    // find out which table is farthest west (and east)
    JTablePanel westTable;
    JTablePanel eastTable;
    int westY;
    int eastY;
    Line2D.Float[] westLines;
    Line2D.Float[] eastLines;
    int[] westEdgeY;
    int[] eastEdgeY;

    _leftIsWest = _leftTable.getX() < _rightTable.getX();

    if (_leftIsWest) {
      westTable = _leftTable;
      eastTable = _rightTable;
      westY = leftY;
      eastY = rightY;
      westLines = _leftLines;
      eastLines = _rightLines;
      westEdgeY = _leftEdgeY;
      eastEdgeY = _rightEdgeY;
    } else {
      westTable = _rightTable;
      eastTable = _leftTable;
      westY = rightY;
      eastY = leftY;
      westLines = _rightLines;
      eastLines = _leftLines;
      westEdgeY = _rightEdgeY;
      eastEdgeY = _leftEdgeY;
    }

    // find out whether the tables are more or less vertically aligned
    boolean aligned = (eastTable.getX() - westTable.getX()) < eastTable.getWidth() / 2;
    // TODO: handle different widths

    int westX;
    if (aligned) {
      westX = westTable.getX() - 10;
      for (int i = 0; i < westEdgeY.length; i++) {
        westLines[i].setLine(westX, westY, westTable.getX(), westEdgeY[i] + westTable.getY());
      }
    } else {
      westX = westTable.getX() + westTable.getWidth() + 10;
      for (int i = 0; i < westEdgeY.length; i++) {
        westLines[i].setLine(
            westX, westY, westTable.getX() + westTable.getWidth(), westEdgeY[i] + westTable.getY());
      }
    }
    int eastX = eastTable.getX() - 10;

    for (int i = 0; i < eastEdgeY.length; i++) {
      eastLines[i].setLine(eastX, eastY, eastTable.getX(), eastEdgeY[i] + eastTable.getY());
    }

    _mainLine.setLine(westX, westY, eastX, eastY);

    setCardinalityPoints();
  }
  /**
   * Sets the CardinalityPoints attribute of the RelationLine object
   *
   * @todo refactor this duplicate code!!!
   */
  private void setCardinalityPoints() {
    // compute vector of length 1
    _mainLength =
        Point2D.distance(
            _mainLine.getX1(), _mainLine.getY1(), _mainLine.getX2(), _mainLine.getY2());
    double vx = (_mainLine.getX2() - _mainLine.getX1()) / _mainLength;
    double vy = (_mainLine.getY2() - _mainLine.getY1()) / _mainLength;
    double cardx = 20.0 * vx;
    double cardy = 20.0 * vy;
    double arrowx = 30.0 * vx;
    double arrowy = 30.0 * vy;
    if (_leftIsWest) {
      _leftArrowPoint.setLocation(_mainLine.getX1() + cardx, _mainLine.getY1() + cardy);
      _rightArrowPoint.setLocation(_mainLine.getX2() - cardx, _mainLine.getY2() - cardy);

      // The left-side arrow head
      _temp.setLocation(_mainLine.getX1() + arrowx, _mainLine.getY1() + arrowy);

      _arrowTransform.setToRotation(Math.PI / 6, _leftArrowPoint.getX(), _leftArrowPoint.getY());
      _arrowTransform.transform(_temp, _leftArrowPoint1);
      _leftArrowLine1.setLine(
          _leftArrowPoint.getX(),
          _leftArrowPoint.getY(),
          _leftArrowPoint1.getX(),
          _leftArrowPoint1.getY());

      _arrowTransform.setToRotation(-Math.PI / 6, _leftArrowPoint.getX(), _leftArrowPoint.getY());
      _arrowTransform.transform(_temp, _leftArrowPoint2);
      _leftArrowLine2.setLine(
          _leftArrowPoint.getX(),
          _leftArrowPoint.getY(),
          _leftArrowPoint2.getX(),
          _leftArrowPoint2.getY());

      _arrowTransform.setToRotation(Math.PI / 2, _leftArrowPoint.getX(), _leftArrowPoint.getY());
      _arrowTransform.transform(_temp, _leftCardinalityPoint);

      _arrowTransform.setToRotation(-Math.PI / 2, _leftArrowPoint.getX(), _leftArrowPoint.getY());
      _arrowTransform.transform(_temp, _leftFkPoint);

      // The right-side arrow head
      _temp.setLocation(_mainLine.getX2() - arrowx, _mainLine.getY2() - arrowy);

      _arrowTransform.setToRotation(Math.PI / 6, _rightArrowPoint.getX(), _rightArrowPoint.getY());
      _arrowTransform.transform(_temp, _rightArrowPoint1);
      _rightArrowLine1.setLine(
          _rightArrowPoint.getX(),
          _rightArrowPoint.getY(),
          _rightArrowPoint1.getX(),
          _rightArrowPoint1.getY());

      _arrowTransform.setToRotation(-Math.PI / 6, _rightArrowPoint.getX(), _rightArrowPoint.getY());
      _arrowTransform.transform(_temp, _rightArrowPoint2);
      _rightArrowLine2.setLine(
          _rightArrowPoint.getX(),
          _rightArrowPoint.getY(),
          _rightArrowPoint2.getX(),
          _rightArrowPoint2.getY());

      _arrowTransform.setToRotation(-Math.PI / 2, _rightArrowPoint.getX(), _rightArrowPoint.getY());
      _arrowTransform.transform(_temp, _rightCardinalityPoint);

      _arrowTransform.setToRotation(Math.PI / 2, _rightArrowPoint.getX(), _rightArrowPoint.getY());
      _arrowTransform.transform(_temp, _rightFkPoint);
    } else {
      _leftArrowPoint.setLocation(_mainLine.getX2() - cardx, _mainLine.getY2() - cardy);
      _rightArrowPoint.setLocation(_mainLine.getX1() + cardx, _mainLine.getY1() + cardy);

      // The left-side arrow head
      _temp.setLocation(_mainLine.getX2() - arrowx, _mainLine.getY2() - arrowy);

      _arrowTransform.setToRotation(Math.PI / 6, _leftArrowPoint.getX(), _leftArrowPoint.getY());
      _arrowTransform.transform(_temp, _leftArrowPoint1);
      _leftArrowLine1.setLine(
          _leftArrowPoint.getX(),
          _leftArrowPoint.getY(),
          _leftArrowPoint1.getX(),
          _leftArrowPoint1.getY());

      _arrowTransform.setToRotation(-Math.PI / 6, _leftArrowPoint.getX(), _leftArrowPoint.getY());
      _arrowTransform.transform(_temp, _leftArrowPoint2);
      _leftArrowLine2.setLine(
          _leftArrowPoint.getX(),
          _leftArrowPoint.getY(),
          _leftArrowPoint2.getX(),
          _leftArrowPoint2.getY());

      _arrowTransform.setToRotation(Math.PI / 2, _leftArrowPoint.getX(), _leftArrowPoint.getY());
      _arrowTransform.transform(_temp, _leftCardinalityPoint);

      _arrowTransform.setToRotation(-Math.PI / 2, _leftArrowPoint.getX(), _leftArrowPoint.getY());
      _arrowTransform.transform(_temp, _leftFkPoint);

      // The right-side arrow head
      _temp.setLocation(_mainLine.getX1() + arrowx, _mainLine.getY1() + arrowy);

      _arrowTransform.setToRotation(Math.PI / 6, _rightArrowPoint.getX(), _rightArrowPoint.getY());
      _arrowTransform.transform(_temp, _rightArrowPoint1);
      _rightArrowLine1.setLine(
          _rightArrowPoint.getX(),
          _rightArrowPoint.getY(),
          _rightArrowPoint1.getX(),
          _rightArrowPoint1.getY());

      _arrowTransform.setToRotation(-Math.PI / 6, _rightArrowPoint.getX(), _rightArrowPoint.getY());
      _arrowTransform.transform(_temp, _rightArrowPoint2);
      _rightArrowLine2.setLine(
          _rightArrowPoint.getX(),
          _rightArrowPoint.getY(),
          _rightArrowPoint2.getX(),
          _rightArrowPoint2.getY());

      _arrowTransform.setToRotation(-Math.PI / 2, _rightArrowPoint.getX(), _rightArrowPoint.getY());
      _arrowTransform.transform(_temp, _rightCardinalityPoint);

      _arrowTransform.setToRotation(Math.PI / 2, _rightArrowPoint.getX(), _rightArrowPoint.getY());
      _arrowTransform.transform(_temp, _rightFkPoint);
    }
  }
 public void line(float x1, float y1, float x2, float y2) {
   line.setLine(x1, y1, x2, y2);
   strokeShape(line);
 }