borderlayout.java

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  else if (str.equals(SOUTH))
    south = component;
  else if (str.equals(EAST))
    east = component;
  else if (str.equals(WEST))
    west = component;
  else if (str.equals(BEFORE_FIRST_LINE))
    firstLine = component;
  else if (str.equals(AFTER_LAST_LINE))
    lastLine = component;
  else if (str.equals(BEFORE_LINE_BEGINS))
    firstItem = component;
  else if (str.equals(AFTER_LINE_ENDS))
    lastItem = component;
  else
    throw new IllegalArgumentException("Constraint value not valid: " + str);
}

/*************************************************************************/

/**
  * Adds a component to the layout in the specified constraint position, 
  * which must be one of the string constants defined in this class.
  *
  * @param constraints The constraint string.
  * @param component The component to add.
  *
  * @exception IllegalArgumentException If the constraint object is not
  * one of the specified constants in this class.
  *
  * @deprecated This method is deprecated in favor of
  * <code>addLayoutComponent(Component, Object)</code>.
  */
public void
addLayoutComponent(String constraints, Component component)
{
  addLayoutComponent(component, constraints);
}

/*************************************************************************/

/**
  * Removes the specified component from the layout.
  *
  * @param component The component to remove from the layout.
  */
public void
removeLayoutComponent(Component component)
{
  if (north == component)
    north = null;
  if (south == component)
    south = null;
  if (east == component)
    east = null;
  if (west == component)
    west = null;
  if (center == component)
    center = null;
  if (firstItem == component)
    firstItem = null;
  if (lastItem == component)
    lastItem = null;
  if (firstLine == component)
    firstLine = null;
  if (lastLine == component)
    lastLine = null;
}

/*************************************************************************/

/**
  * Returns the minimum size of the specified container using this layout.
  *
  * @param target The container to calculate the minimum size for.
  *
  * @return The minimum size of the container
  */
public Dimension 
minimumLayoutSize(Container target)
{
  return calcSize(target, MIN);
}

/*************************************************************************/

/**
  * Returns the preferred size of the specified container using this layout.
  *
  * @param target The container to calculate the preferred size for.
  *
  * @return The preferred size of the container
  */
public Dimension 
preferredLayoutSize(Container target)
{
  return calcSize(target, PREF);
}

/*************************************************************************/

/**
  * Returns the maximum size of the specified container using this layout.
  *
  * @param target The container to calculate the maximum size for.
  *
  * @return The maximum size of the container
  */
public Dimension 
maximumLayoutSize(Container target)
{
  return calcSize(target, MAX);
}

/*************************************************************************/

/**
  * Returns the X axis alignment, which is a <code>float</code> indicating
  * where along the X axis this container wishs to position its layout.
  * 0 indicates align to the left, 1 indicates align to the right, and 0.5
  * indicates align to the center.
  *
  * @param parent The parent container.
  *
  * @return The X alignment value.
  */
public float
getLayoutAlignmentX(Container parent)
{
  return(parent.getAlignmentX());
}

/*************************************************************************/

/**
  * Returns the Y axis alignment, which is a <code>float</code> indicating
  * where along the Y axis this container wishs to position its layout.
  * 0 indicates align to the top, 1 indicates align to the bottom, and 0.5
  * indicates align to the center.
  *
  * @param parent The parent container.
  *
  * @return The Y alignment value.
  */
public float
getLayoutAlignmentY(Container parent)
{
  return(parent.getAlignmentY());
}

/*************************************************************************/

/**
  * Instructs this object to discard any layout information it might
  * have cached.
  *
  * @param parent The parent container.
  */
public void
invalidateLayout(Container parent)
{
}

/*************************************************************************/

/**
  * Lays out the specified container according to the constraints
  * in this object.
  *
  * @param target The container to lay out.
  */
public void
layoutContainer(Container target)
{
  synchronized (target.getTreeLock ())
    {
      Insets i = target.getInsets();

      ComponentOrientation orient = target.getComponentOrientation ();
      boolean left_to_right = orient.isLeftToRight ();

      Component my_north = north;
      Component my_east = east;
      Component my_south = south;
      Component my_west = west;

      // Note that we currently don't handle vertical layouts.  Neither
      // does JDK 1.3.
      if (firstLine != null)
	my_north = firstLine;
      if (lastLine != null)
	my_south = lastLine;
      if (firstItem != null)
	{
	  if (left_to_right)
	    my_west = firstItem;
	  else
	    my_east = firstItem;
	}
      if (lastItem != null)
	{
	  if (left_to_right)
	    my_east = lastItem;
	  else
	    my_west = lastItem;
	}

      Dimension c = calcCompSize(center, PREF);
      Dimension n = calcCompSize(my_north, PREF);
      Dimension s = calcCompSize(my_south, PREF);
      Dimension e = calcCompSize(my_east, PREF);
      Dimension w = calcCompSize(my_west, PREF);
      Dimension t = target.getSize();

      /*
	<-> hgap     <-> hgap
	+----------------------------+          }
	|t                           |          } i.top
	|  +----------------------+  |  --- y1  }
	|  |n                     |  |
	|  +----------------------+  |          } vgap
	|  +---+ +----------+ +---+  |  --- y2  }        }
	|  |w  | |c         | |e  |  |                   } hh
	|  +---+ +----------+ +---+  |          } vgap   }
	|  +----------------------+  |  --- y3  }
	|  |s                     |  |
	|  +----------------------+  |          }
	|                            |          } i.bottom
	+----------------------------+          }
	|x1   |x2          |x3
	<---------------------->
	<-->         ww           <-->
	i.left                    i.right
      */

      int x1 = i.left;
      int x2 = x1 + w.width + hgap;
      int x3 = t.width - i.right - e.width;
      int ww = t.width - i.right - i.left;

      int y1 = i.top;
      int y2 = y1 + n.height + vgap;
      int y3 = t.height - i.bottom - s.height;
      int hh = y3-y2-vgap;

      setBounds(center, x2, y2, x3-x2-hgap, hh);
      setBounds(my_north, x1, y1, ww, n.height);
      setBounds(my_south, x1, y3, ww, s.height);
      setBounds(my_west, x1, y2, w.width, hh);
      setBounds(my_east, x3, y2, e.width, hh);
    }
}

/*************************************************************************/

/**
  * Returns a string representation of this layout manager.
  *
  * @return A string representation of this object.
  */
public String
toString()
{
  return getClass().getName() + "[hgap=" + hgap + ",vgap=" + vgap + "]";
}

private void
setBounds(Component comp, int x, int y, int w, int h)
{
  if (comp == null)
    return;
  comp.setBounds(x, y, w, h);
}

// Some constants for use with calcSize().
private static final int MIN = 0;
private static final int MAX = 1;
private static final int PREF = 2;

private Dimension
calcCompSize(Component comp, int what)
{
  if (comp == null)
    return new Dimension(0, 0);
  if (what == MIN)
    return comp.getMinimumSize();
  else if (what == MAX)
    return comp.getMaximumSize();
  return comp.getPreferredSize();
}

// This is a helper function used to compute the various sizes for
// this layout.
private Dimension
calcSize(Container target, int what)
{
  synchronized (target.getTreeLock ())
    {
      Insets ins = target.getInsets();

      ComponentOrientation orient = target.getComponentOrientation ();
      boolean left_to_right = orient.isLeftToRight ();

      Component my_north = north;
      Component my_east = east;
      Component my_south = south;
      Component my_west = west;

      // Note that we currently don't handle vertical layouts.  Neither
      // does JDK 1.3.
      if (firstLine != null)
	my_north = firstLine;
      if (lastLine != null)
	my_south = lastLine;
      if (firstItem != null)
	{
	  if (left_to_right)
	    my_west = firstItem;
	  else
	    my_east = firstItem;
	}
      if (lastItem != null)
	{
	  if (left_to_right)
	    my_east = lastItem;
	  else
	    my_west = lastItem;
	}
      
      Dimension ndim = calcCompSize(my_north, what);
      Dimension sdim = calcCompSize(my_south, what);
      Dimension edim = calcCompSize(my_east, what);
      Dimension wdim = calcCompSize(my_west, what);
      Dimension cdim = calcCompSize(center, what);

      int width = edim.width + cdim.width + wdim.width + (hgap * 2);
      if (ndim.width > width)
	width = ndim.width;
      if (sdim.width > width)
	width = sdim.width;

      width += (ins.left + ins.right);

      int height = edim.height;
      if (cdim.height > height)
	height = cdim.height;
      if (wdim.height > height)
	height = wdim.height;

      height += (ndim.height + sdim.height + (vgap * 2) + ins.top + ins.bottom);

      return(new Dimension(width, height));
    }
}
} // class BorderLayout