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Class com.sun.java.swing.ScrollPaneLayout

java.lang.Object
  |
  +--com.sun.java.swing.ScrollPaneLayout

public class ScrollPaneLayout

extends java.lang.Object

implements java.awt.LayoutManager, ScrollPaneConstants, java.io.Serializable

The layout manager used by JScrollPane. JScrollPaneLayout is responsible for nine components: a viewport, two scrollbars, a row header, a column header, and four "corner" components.

Warning: serialized objects of this class will not be compatible with future swing releases. The current serialization support is appropriate for short term storage or RMI between Swing1.0 applications. It will not be possible to load serialized Swing1.0 objects with future releases of Swing. The JDK1.2 release of Swing will be the compatibility baseline for the serialized form of Swing objects.

See Also:

JScrollPane, JViewport, Serialized Form

Field Summary

JViewport	colHead The column-header component
int	hsbPolicy The display policy for the horizontal scrollbar.
JScrollBar	hsb The horizontal scrollbar
java.awt.Component	lowerLeft The component at the lower left corner
java.awt.Component	lowerRight The component at the lower right corner
JViewport	rowHead The row-header component
java.awt.Component	upperLeft The component at the upper left corner
java.awt.Component	upperRight The component at the upper right corner
JViewport	viewport The JViewport that displays the pane's contents
int	vsbPolicy The display policy for the vertical scrollbar.
JScrollBar	vsb The vertical scrollbar

Method Summary

void	addLayoutComponent(java.lang.String s, java.awt.Component c) Adds the specified component to the layout, identifying it as one of: ScrollPaneConstants.
java.awt.Component	addSingletonComponent(java.awt.Component oldC, java.awt.Component newC) The method used to replace an existing component (if any) with a new one.
JViewport	getColumnHeader() Returns the column header component.
java.awt.Component	getCorner(java.lang.String key) Returns the component at the specified corner, where the corner specification is one of: ScrollPaneConstants.
int	getHorizontalScrollBarPolicy() Returns the horizontal scrollbar-display policy.
JScrollBar	getHorizontalScrollBar() Returns the horizontal scrollbar.
JViewport	getRowHeader() Returns the row header component.
int	getVerticalScrollBarPolicy() Returns the vertical scrollbar-display policy.
JScrollBar	getVerticalScrollBar() Returns the vertical scrollbar.
java.awt.Rectangle	getViewportBorderBounds(JScrollPane sp) Returns the bounds of the border around the specified scroll pane's viewport.
JViewport	getViewport() Returns the view port object.
void	layoutContainer(java.awt.Container parent) Layout the scrollpane according to the following constraints: The row header, if present and visible, gets its preferred height and the viewports width.
java.awt.Dimension	minimumLayoutSize(java.awt.Container parent) The minimum size of a ScrollPane is the size of the insets plus minimum size of the viewport, plus the scrollpane's viewportBorder insets, plus the minimum size of the visible headers, plus the minimum size of the scrollbars whose displayPolicy isn't NEVER.
java.awt.Dimension	preferredLayoutSize(java.awt.Container parent) The preferred size of a ScrollPane is the size of the insets, plus the preferred size of the viewport, plus the preferred size of the visible headers, plus the preferred size of the scrollbars that will appear given the current view and the current scrollbar displayPolicies.
void	removeLayoutComponent(java.awt.Component c) Removes the specified component from the layout.
void	setHorizontalScrollBarPolicy(int x) Returns the horizontal scrollbar-display policy, where the options are: ScrollPaneConstants.
void	setVerticalScrollBarPolicy(int x) Returns the vertical scrollbar-display policy, where the options are: ScrollPaneConstants.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notifyAll, notify, toString, wait, wait, wait

Field Detail

viewport

protected JViewport viewport

The JViewport that displays the pane's contents

vsb

protected JScrollBar vsb

The vertical scrollbar

hsb

protected JScrollBar hsb

The horizontal scrollbar

rowHead

protected JViewport rowHead

The row-header component

colHead

protected JViewport colHead

The column-header component

lowerLeft

protected java.awt.Component lowerLeft

The component at the lower left corner

lowerRight

protected java.awt.Component lowerRight

The component at the lower right corner

upperLeft

protected java.awt.Component upperLeft

The component at the upper left corner

upperRight

protected java.awt.Component upperRight

The component at the upper right corner

vsbPolicy

protected int vsbPolicy

The display policy for the vertical scrollbar. Default = As Needed

hsbPolicy

protected int hsbPolicy

The display policy for the horizontal scrollbar. Default = As Needed

Method Detail

addSingletonComponent

protected java.awt.Component addSingletonComponent(java.awt.Component oldC,
                                          java.awt.Component newC)

The method used to replace an existing component (if any) with a new one. Used to add each different kind of component to a JScrollPane, since there can be one and only one left corner, vertical scrollbar, and so on. So only one of each subcomponent is allowed, the old one is removed (if it exists) when a new one is added.

Parameters:

oldC - the Component to replace

newC - the Component to add

addLayoutComponent

public void addLayoutComponent(java.lang.String s,
                               java.awt.Component c)

Adds the specified component to the layout, identifying it as one of:

• ScrollPaneConstants.VIEWPORT
• ScrollPaneConstants.VERTICAL_SCROLLBAR
• ScrollPaneConstants.HORIZONTAL_SCROLLBAR
• ScrollPaneConstants.ROW_HEADER
• ScrollPaneConstants.COLUMN_HEADER
• ScrollPaneConstants.LOWER_LEFT_CORNER
• ScrollPaneConstants.LOWER_RIGHT_CORNER
• ScrollPaneConstants.UPPER_LEFT_CORNER
• ScrollPaneConstants.UPPER_RIGHT_CORNER

Specified by:

addLayoutComponent(java.lang.String, java.awt.Component) in interface java.awt.LayoutManager

Parameters:

s - the component identifier

comp - the the component to be added

removeLayoutComponent

public void removeLayoutComponent(java.awt.Component c)

Removes the specified component from the layout.

Specified by:

removeLayoutComponent(java.awt.Component) in interface java.awt.LayoutManager

Parameters:

comp - the component to remove

getVerticalScrollBarPolicy

public int getVerticalScrollBarPolicy()

Returns the vertical scrollbar-display policy.

Returns:

an int giving the display policy

See Also:

setVerticalScrollBarPolicy

setVerticalScrollBarPolicy

public void setVerticalScrollBarPolicy(int x)

Returns the vertical scrollbar-display policy, where the options are:

• ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED
• ScrollPaneConstants.VERTICAL_SCROLLBAR_NEVER
• ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS

Parameters:

x - an int giving the display policy

getHorizontalScrollBarPolicy

public int getHorizontalScrollBarPolicy()

Returns the horizontal scrollbar-display policy.

Returns:

an int giving the display policy

See Also:

setHorizontalScrollBarPolicy

setHorizontalScrollBarPolicy

public void setHorizontalScrollBarPolicy(int x)

Returns the horizontal scrollbar-display policy, where the options are:

• ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED
• ScrollPaneConstants.HOTRIZONTAL_SCROLLBAR_NEVER
• ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS

Parameters:

x - an int giving the display policy

getViewport

public JViewport getViewport()

Returns the view port object.

Returns:

the JViewport object that displays the scrollable contents

getHorizontalScrollBar

public JScrollBar getHorizontalScrollBar()

Returns the horizontal scrollbar.

Returns:

the JScrollbar object that handles horizontal scrolling

getVerticalScrollBar

public JScrollBar getVerticalScrollBar()

Returns the vertical scrollbar.

Returns:

the JScrollbar object that handles vertical scrolling

getRowHeader

public JViewport getRowHeader()

Returns the row header component.

Returns:

the JViewport object that is the row header

getColumnHeader

public JViewport getColumnHeader()

Returns the column header component.

Returns:

the JViewport object that is the column header

getCorner

public java.awt.Component getCorner(java.lang.String key)

Returns the component at the specified corner, where the corner specification is one of:

• ScrollPaneConstants.LOWER_LEFT_CORNER
• ScrollPaneConstants.LOWER_RIGHT_CORNER
• ScrollPaneConstants.UPPER_LEFT_CORNER
• ScrollPaneConstants.UPPER_RIGHT_CORNER

Returns:

the Component at the specified corner

preferredLayoutSize

public java.awt.Dimension preferredLayoutSize(java.awt.Container parent)

The preferred size of a ScrollPane is the size of the insets, plus the preferred size of the viewport, plus the preferred size of the visible headers, plus the preferred size of the scrollbars that will appear given the current view and the current scrollbar displayPolicies.

Specified by:

preferredLayoutSize(java.awt.Container) in interface java.awt.LayoutManager

Parameters:

parent - the Container that will be laid out

Returns:

a Dimension object specifying the preferred size of the viewport and any scrollbars.

See Also:

ViewportLayout, java.awt.LayoutManager

minimumLayoutSize

public java.awt.Dimension minimumLayoutSize(java.awt.Container parent)

The minimum size of a ScrollPane is the size of the insets plus minimum size of the viewport, plus the scrollpane's viewportBorder insets, plus the minimum size of the visible headers, plus the minimum size of the scrollbars whose displayPolicy isn't NEVER.

Specified by:

minimumLayoutSize(java.awt.Container) in interface java.awt.LayoutManager

Parameters:

parent - the Container that will be laid out

Returns:

a Dimension object specifying the minimum size

layoutContainer

public void layoutContainer(java.awt.Container parent)

Layout the scrollpane according to the following constraints:

• The row header, if present and visible, gets its preferred height and the viewports width.
• The column header, if present and visible, gets its preferred width and the viewports height.
• If a vertical scrollbar is needed, i.e. if the viewports extent height is smaller than its view height or if the displayPolicy is ALWAYS, it's treated like the row header wrt it's dimensions and it's made visible.
• If a horizontal scrollbar is needed it's treated like the column header (and see the vertical scrollbar item).
• If the scrollpane has a non-null viewportBorder, then space is allocated for that.
• The viewport gets the space available after accounting for the previous constraints.
• The corner components, if provided, are aligned with the ends of the scrollbars and headers. If there's a vertical scrollbar the right corners appear, if there's a horizontal scrollbar the lower corners appear, a row header gets left corners and a column header gets upper corners.

Specified by:

layoutContainer(java.awt.Container) in interface java.awt.LayoutManager

Parameters:

parent - the Container to lay out

getViewportBorderBounds

public java.awt.Rectangle getViewportBorderBounds(JScrollPane sp)

Returns the bounds of the border around the specified scroll pane's viewport.

Returns:

a Rectangle containing the size and position of the viewport border