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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package javax.swing;

import javax.swing.plaf.*;
import javax.swing.border.*;
import javax.swing.event.*;
import javax.accessibility.*;

import java.awt.Component;
import java.awt.ComponentOrientation;
import java.awt.Rectangle;
import java.awt.Insets;
import java.awt.LayoutManager;
import java.awt.Point;

import java.io.ObjectOutputStream;
import java.io.IOException;

import java.beans.JavaBean;
import java.beans.BeanProperty;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.beans.Transient;

Provides a scrollable view of a lightweight component. A JScrollPane manages a viewport, optional vertical and horizontal scroll bars, and optional row and column heading viewports. You can find task-oriented documentation of JScrollPane in How to Use Scroll Panes, a section in The Java Tutorial. Note that JScrollPane does not support heavyweight components.
Example

The JViewport provides a window, or "viewport" onto a data source -- for example, a text file. That data source is the "scrollable client" (aka data model) displayed by the JViewport view. A JScrollPane basically consists of JScrollBars, a JViewport, and the wiring between them, as shown in the diagram at right.

In addition to the scroll bars and viewport, a JScrollPane can have a column header and a row header. Each of these is a JViewport object that you specify with setRowHeaderView, and setColumnHeaderView. The column header viewport automatically scrolls left and right, tracking the left-right scrolling of the main viewport. (It never scrolls vertically, however.) The row header acts in a similar fashion.

Where two scroll bars meet, the row header meets the column header, or a scroll bar meets one of the headers, both components stop short of the corner, leaving a rectangular space which is, by default, empty. These spaces can potentially exist in any number of the four corners. In the previous diagram, the top right space is present and identified by the label "corner component".

Any number of these empty spaces can be replaced by using the setCorner method to add a component to a particular corner. (Note: The same component cannot be added to multiple corners.) This is useful if there's some extra decoration or function you'd like to add to the scroll pane. The size of each corner component is entirely determined by the size of the headers and/or scroll bars that surround it.

A corner component will only be visible if there is an empty space in that corner for it to exist in. For example, consider a component set into the top right corner of a scroll pane with a column header. If the scroll pane's vertical scrollbar is not present, perhaps because the view component hasn't grown large enough to require it, then the corner component will not be shown (since there is no empty space in that corner created by the meeting of the header and vertical scroll bar). Forcing the scroll bar to always be shown, using setVerticalScrollBarPolicy(VERTICAL_SCROLLBAR_ALWAYS), will ensure that the space for the corner component always exists.

To add a border around the main viewport, you can use setViewportBorder. (Of course, you can also add a border around the whole scroll pane using setBorder.)

A common operation to want to do is to set the background color that will be used if the main viewport view is smaller than the viewport, or is not opaque. This can be accomplished by setting the background color of the viewport, via scrollPane.getViewport().setBackground(). The reason for setting the color of the viewport and not the scrollpane is that by default JViewport is opaque which, among other things, means it will completely fill in its background using its background color. Therefore when JScrollPane draws its background the viewport will usually draw over it.

By default JScrollPane uses ScrollPaneLayout to handle the layout of its child Components. ScrollPaneLayout determines the size to make the viewport view in one of two ways:

  1. If the view implements Scrollable a combination of getPreferredScrollableViewportSize, getScrollableTracksViewportWidth and getScrollableTracksViewportHeightis used, otherwise
  2. getPreferredSize is used.

Warning: Swing is not thread safe. For more information see Swing's Threading Policy.

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 applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans™ has been added to the java.beans package. Please see XMLEncoder.

Author:Hans Muller
See Also:
Since:1.2
/** * Provides a scrollable view of a lightweight component. * A <code>JScrollPane</code> manages a viewport, optional * vertical and horizontal scroll bars, and optional row and * column heading viewports. * You can find task-oriented documentation of <code>JScrollPane</code> in * <a href="http://docs.oracle.com/javase/tutorial/uiswing/components/scrollpane.html">How to Use Scroll Panes</a>, * a section in <em>The Java Tutorial</em>. Note that * <code>JScrollPane</code> does not support heavyweight components. * * <table class="borderless" style="float:right"> * <caption>Example</caption> * <TR> * <TD style="text-align:center"> * <P STYLE="TEXT-ALIGN:CENTER"><IMG SRC="doc-files/JScrollPane-1.gif" * alt="The following text describes this image." * WIDTH="256" HEIGHT="248" STYLE="FLOAT:BOTTOM; BORDER:0px"> * </TD> * </TR> * </TABLE> * The <code>JViewport</code> provides a window, * or &quot;viewport&quot; onto a data * source -- for example, a text file. That data source is the * &quot;scrollable client&quot; (aka data model) displayed by the * <code>JViewport</code> view. * A <code>JScrollPane</code> basically consists of <code>JScrollBar</code>s, * a <code>JViewport</code>, and the wiring between them, * as shown in the diagram at right. * <p> * In addition to the scroll bars and viewport, * a <code>JScrollPane</code> can have a * column header and a row header. Each of these is a * <code>JViewport</code> object that * you specify with <code>setRowHeaderView</code>, * and <code>setColumnHeaderView</code>. * The column header viewport automatically scrolls left and right, tracking * the left-right scrolling of the main viewport. * (It never scrolls vertically, however.) * The row header acts in a similar fashion. * <p> * Where two scroll bars meet, the row header meets the column header, * or a scroll bar meets one of the headers, both components stop short * of the corner, leaving a rectangular space which is, by default, empty. * These spaces can potentially exist in any number of the four corners. * In the previous diagram, the top right space is present and identified * by the label "corner component". * <p> * Any number of these empty spaces can be replaced by using the * <code>setCorner</code> method to add a component to a particular corner. * (Note: The same component cannot be added to multiple corners.) * This is useful if there's * some extra decoration or function you'd like to add to the scroll pane. * The size of each corner component is entirely determined by the size of the * headers and/or scroll bars that surround it. * <p> * A corner component will only be visible if there is an empty space in that * corner for it to exist in. For example, consider a component set into the * top right corner of a scroll pane with a column header. If the scroll pane's * vertical scrollbar is not present, perhaps because the view component hasn't * grown large enough to require it, then the corner component will not be * shown (since there is no empty space in that corner created by the meeting * of the header and vertical scroll bar). Forcing the scroll bar to always be * shown, using * <code>setVerticalScrollBarPolicy(VERTICAL_SCROLLBAR_ALWAYS)</code>, * will ensure that the space for the corner component always exists. * <p> * To add a border around the main viewport, * you can use <code>setViewportBorder</code>. * (Of course, you can also add a border around the whole scroll pane using * <code>setBorder</code>.) * <p> * A common operation to want to do is to set the background color that will * be used if the main viewport view is smaller than the viewport, or is * not opaque. This can be accomplished by setting the background color * of the viewport, via <code>scrollPane.getViewport().setBackground()</code>. * The reason for setting the color of the viewport and not the scrollpane * is that by default <code>JViewport</code> is opaque * which, among other things, means it will completely fill * in its background using its background color. Therefore when * <code>JScrollPane</code> draws its background the viewport will * usually draw over it. * <p> * By default <code>JScrollPane</code> uses <code>ScrollPaneLayout</code> * to handle the layout of its child Components. <code>ScrollPaneLayout</code> * determines the size to make the viewport view in one of two ways: * <ol> * <li>If the view implements <code>Scrollable</code> * a combination of <code>getPreferredScrollableViewportSize</code>, * <code>getScrollableTracksViewportWidth</code> and * <code>getScrollableTracksViewportHeight</code>is used, otherwise * <li><code>getPreferredSize</code> is used. * </ol> * <p> * <strong>Warning:</strong> Swing is not thread safe. For more * information see <a * href="package-summary.html#threading">Swing's Threading * Policy</a>. * <p> * <strong>Warning:</strong> * 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 applications running * the same version of Swing. As of 1.4, support for long term storage * of all JavaBeans&trade; * has been added to the <code>java.beans</code> package. * Please see {@link java.beans.XMLEncoder}. * * @see JScrollBar * @see JViewport * @see ScrollPaneLayout * @see Scrollable * @see Component#getPreferredSize * @see #setViewportView * @see #setRowHeaderView * @see #setColumnHeaderView * @see #setCorner * @see #setViewportBorder * * @author Hans Muller * @since 1.2 */
@JavaBean(defaultProperty = "UI", description = "A specialized container that manages a viewport, optional scrollbars and headers") @SwingContainer(delegate = "getViewport") @SuppressWarnings("serial") // Same-version serialization only public class JScrollPane extends JComponent implements ScrollPaneConstants, Accessible { private Border viewportBorder;
See Also:
/** * @see #getUIClassID * @see #readObject */
private static final String uiClassID = "ScrollPaneUI";
The display policy for the vertical scrollbar. The default is ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED.
See Also:
  • setVerticalScrollBarPolicy
/** * The display policy for the vertical scrollbar. * The default is * <code>ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED</code>. * @see #setVerticalScrollBarPolicy */
protected int verticalScrollBarPolicy = VERTICAL_SCROLLBAR_AS_NEEDED;
The display policy for the horizontal scrollbar. The default is ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED.
See Also:
  • setHorizontalScrollBarPolicy
/** * The display policy for the horizontal scrollbar. * The default is * <code>ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED</code>. * @see #setHorizontalScrollBarPolicy */
protected int horizontalScrollBarPolicy = HORIZONTAL_SCROLLBAR_AS_NEEDED;
The scrollpane's viewport child. Default is an empty JViewport.
See Also:
  • setViewport
/** * The scrollpane's viewport child. Default is an empty * <code>JViewport</code>. * @see #setViewport */
protected JViewport viewport;
The scrollpane's vertical scrollbar child. Default is a JScrollBar.
See Also:
  • setVerticalScrollBar
/** * The scrollpane's vertical scrollbar child. * Default is a <code>JScrollBar</code>. * @see #setVerticalScrollBar */
protected JScrollBar verticalScrollBar;
The scrollpane's horizontal scrollbar child. Default is a JScrollBar.
See Also:
  • setHorizontalScrollBar
/** * The scrollpane's horizontal scrollbar child. * Default is a <code>JScrollBar</code>. * @see #setHorizontalScrollBar */
protected JScrollBar horizontalScrollBar;
The row header child. Default is null.
See Also:
  • setRowHeader
/** * The row header child. Default is <code>null</code>. * @see #setRowHeader */
protected JViewport rowHeader;
The column header child. Default is null.
See Also:
  • setColumnHeader
/** * The column header child. Default is <code>null</code>. * @see #setColumnHeader */
protected JViewport columnHeader;
The component to display in the lower left corner. Default is null.
See Also:
  • setCorner
/** * The component to display in the lower left corner. * Default is <code>null</code>. * @see #setCorner */
protected Component lowerLeft;
The component to display in the lower right corner. Default is null.
See Also:
  • setCorner
/** * The component to display in the lower right corner. * Default is <code>null</code>. * @see #setCorner */
protected Component lowerRight;
The component to display in the upper left corner. Default is null.
See Also:
  • setCorner
/** * The component to display in the upper left corner. * Default is <code>null</code>. * @see #setCorner */
protected Component upperLeft;
The component to display in the upper right corner. Default is null.
See Also:
  • setCorner
/** * The component to display in the upper right corner. * Default is <code>null</code>. * @see #setCorner */
protected Component upperRight; /* * State flag for mouse wheel scrolling */ private boolean wheelScrollState = true;
Creates a JScrollPane that displays the view component in a viewport whose view position can be controlled with a pair of scrollbars. The scrollbar policies specify when the scrollbars are displayed, For example, if vsbPolicy is VERTICAL_SCROLLBAR_AS_NEEDED then the vertical scrollbar only appears if the view doesn't fit vertically. The available policy settings are listed at setVerticalScrollBarPolicy and setHorizontalScrollBarPolicy.
Params:
  • view – the component to display in the scrollpanes viewport
  • vsbPolicy – an integer that specifies the vertical scrollbar policy
  • hsbPolicy – an integer that specifies the horizontal scrollbar policy
See Also:
/** * Creates a <code>JScrollPane</code> that displays the view * component in a viewport * whose view position can be controlled with a pair of scrollbars. * The scrollbar policies specify when the scrollbars are displayed, * For example, if <code>vsbPolicy</code> is * <code>VERTICAL_SCROLLBAR_AS_NEEDED</code> * then the vertical scrollbar only appears if the view doesn't fit * vertically. The available policy settings are listed at * {@link #setVerticalScrollBarPolicy} and * {@link #setHorizontalScrollBarPolicy}. * * @see #setViewportView * * @param view the component to display in the scrollpanes viewport * @param vsbPolicy an integer that specifies the vertical * scrollbar policy * @param hsbPolicy an integer that specifies the horizontal * scrollbar policy */
public JScrollPane(Component view, int vsbPolicy, int hsbPolicy) { setLayout(new ScrollPaneLayout.UIResource()); setVerticalScrollBarPolicy(vsbPolicy); setHorizontalScrollBarPolicy(hsbPolicy); setViewport(createViewport()); setVerticalScrollBar(createVerticalScrollBar()); setHorizontalScrollBar(createHorizontalScrollBar()); if (view != null) { setViewportView(view); } setUIProperty("opaque",true); updateUI(); if (!this.getComponentOrientation().isLeftToRight()) { viewport.setViewPosition(new Point(Integer.MAX_VALUE, 0)); } }
Creates a JScrollPane that displays the contents of the specified component, where both horizontal and vertical scrollbars appear whenever the component's contents are larger than the view.
Params:
  • view – the component to display in the scrollpane's viewport
See Also:
  • setViewportView
/** * Creates a <code>JScrollPane</code> that displays the * contents of the specified * component, where both horizontal and vertical scrollbars appear * whenever the component's contents are larger than the view. * * @see #setViewportView * @param view the component to display in the scrollpane's viewport */
public JScrollPane(Component view) { this(view, VERTICAL_SCROLLBAR_AS_NEEDED, HORIZONTAL_SCROLLBAR_AS_NEEDED); }
Creates an empty (no viewport view) JScrollPane with specified scrollbar policies. The available policy settings are listed at setVerticalScrollBarPolicy and setHorizontalScrollBarPolicy.
Params:
  • vsbPolicy – an integer that specifies the vertical scrollbar policy
  • hsbPolicy – an integer that specifies the horizontal scrollbar policy
See Also:
/** * Creates an empty (no viewport view) <code>JScrollPane</code> * with specified * scrollbar policies. The available policy settings are listed at * {@link #setVerticalScrollBarPolicy} and * {@link #setHorizontalScrollBarPolicy}. * * @see #setViewportView * * @param vsbPolicy an integer that specifies the vertical * scrollbar policy * @param hsbPolicy an integer that specifies the horizontal * scrollbar policy */
public JScrollPane(int vsbPolicy, int hsbPolicy) { this(null, vsbPolicy, hsbPolicy); }
Creates an empty (no viewport view) JScrollPane where both horizontal and vertical scrollbars appear when needed.
/** * Creates an empty (no viewport view) <code>JScrollPane</code> * where both horizontal and vertical scrollbars appear when needed. */
public JScrollPane() { this(null, VERTICAL_SCROLLBAR_AS_NEEDED, HORIZONTAL_SCROLLBAR_AS_NEEDED); }
Returns the look and feel (L&F) object that renders this component.
See Also:
Returns:the ScrollPaneUI object that renders this component
/** * Returns the look and feel (L&amp;F) object that renders this component. * * @return the <code>ScrollPaneUI</code> object that renders this * component * @see #setUI */
@BeanProperty(hidden = true, visualUpdate = true, description = "The UI object that implements the Component's LookAndFeel.") public ScrollPaneUI getUI() { return (ScrollPaneUI)ui; }
Sets the ScrollPaneUI object that provides the look and feel (L&F) for this component.
Params:
  • ui – the ScrollPaneUI L&F object
See Also:
/** * Sets the <code>ScrollPaneUI</code> object that provides the * look and feel (L&amp;F) for this component. * * @param ui the <code>ScrollPaneUI</code> L&amp;F object * @see #getUI */
public void setUI(ScrollPaneUI ui) { super.setUI(ui); }
Replaces the current ScrollPaneUI object with a version from the current default look and feel. To be called when the default look and feel changes.
See Also:
/** * Replaces the current <code>ScrollPaneUI</code> object with a version * from the current default look and feel. * To be called when the default look and feel changes. * * @see JComponent#updateUI * @see UIManager#getUI */
public void updateUI() { setUI((ScrollPaneUI)UIManager.getUI(this)); }
Returns the suffix used to construct the name of the L&F class used to render this component.
See Also:
Returns:the string "ScrollPaneUI"
/** * Returns the suffix used to construct the name of the L&amp;F class used to * render this component. * * @return the string "ScrollPaneUI" * @see JComponent#getUIClassID * @see UIDefaults#getUI */
@BeanProperty(bound = false, hidden = true) public String getUIClassID() { return uiClassID; }
Sets the layout manager for this JScrollPane. This method overrides setLayout in java.awt.Container to ensure that only LayoutManagers which are subclasses of ScrollPaneLayout can be used in a JScrollPane. If layout is non-null, this will invoke syncWithScrollPane on it.
Params:
  • layout – the specified layout manager
Throws:
See Also:
/** * Sets the layout manager for this <code>JScrollPane</code>. * This method overrides <code>setLayout</code> in * <code>java.awt.Container</code> to ensure that only * <code>LayoutManager</code>s which * are subclasses of <code>ScrollPaneLayout</code> can be used in a * <code>JScrollPane</code>. If <code>layout</code> is non-null, this * will invoke <code>syncWithScrollPane</code> on it. * * @param layout the specified layout manager * @exception ClassCastException if layout is not a * <code>ScrollPaneLayout</code> * @see java.awt.Container#getLayout * @see java.awt.Container#setLayout */
public void setLayout(LayoutManager layout) { if (layout instanceof ScrollPaneLayout) { super.setLayout(layout); ((ScrollPaneLayout)layout).syncWithScrollPane(this); } else if (layout == null) { super.setLayout(layout); } else { String s = "layout of JScrollPane must be a ScrollPaneLayout"; throw new ClassCastException(s); } }
Overridden to return true so that any calls to revalidate on any descendants of this JScrollPane will cause the entire tree beginning with this JScrollPane to be validated.
See Also:
Returns:true
/** * Overridden to return true so that any calls to <code>revalidate</code> * on any descendants of this <code>JScrollPane</code> will cause the * entire tree beginning with this <code>JScrollPane</code> to be * validated. * * @return true * @see java.awt.Container#validate * @see JComponent#revalidate * @see JComponent#isValidateRoot * @see java.awt.Container#isValidateRoot */
@Override @BeanProperty(hidden = true) public boolean isValidateRoot() { return true; }
Returns the vertical scroll bar policy value.
See Also:
Returns:the verticalScrollBarPolicy property
/** * Returns the vertical scroll bar policy value. * @return the <code>verticalScrollBarPolicy</code> property * @see #setVerticalScrollBarPolicy */
public int getVerticalScrollBarPolicy() { return verticalScrollBarPolicy; }
Determines when the vertical scrollbar appears in the scrollpane. Legal values are:
  • ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED
  • ScrollPaneConstants.VERTICAL_SCROLLBAR_NEVER
  • ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS
Params:
  • policy – one of the three values listed above
Throws:
See Also:
/** * Determines when the vertical scrollbar appears in the scrollpane. * Legal values are: * <ul> * <li><code>ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED</code> * <li><code>ScrollPaneConstants.VERTICAL_SCROLLBAR_NEVER</code> * <li><code>ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS</code> * </ul> * * @param policy one of the three values listed above * @exception IllegalArgumentException if <code>policy</code> * is not one of the legal values shown above * @see #getVerticalScrollBarPolicy */
@BeanProperty(preferred = true, enumerationValues = { "ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED", "ScrollPaneConstants.VERTICAL_SCROLLBAR_NEVER", "ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS"}, description = "The scrollpane vertical scrollbar policy") public void setVerticalScrollBarPolicy(int policy) { switch (policy) { case VERTICAL_SCROLLBAR_AS_NEEDED: case VERTICAL_SCROLLBAR_NEVER: case VERTICAL_SCROLLBAR_ALWAYS: break; default: throw new IllegalArgumentException("invalid verticalScrollBarPolicy"); } int old = verticalScrollBarPolicy; verticalScrollBarPolicy = policy; firePropertyChange("verticalScrollBarPolicy", old, policy); revalidate(); repaint(); }
Returns the horizontal scroll bar policy value.
See Also:
Returns:the horizontalScrollBarPolicy property
/** * Returns the horizontal scroll bar policy value. * @return the <code>horizontalScrollBarPolicy</code> property * @see #setHorizontalScrollBarPolicy */
public int getHorizontalScrollBarPolicy() { return horizontalScrollBarPolicy; }
Determines when the horizontal scrollbar appears in the scrollpane. The options are:
  • ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED
  • ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER
  • ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS
Params:
  • policy – one of the three values listed above
Throws:
See Also:
/** * Determines when the horizontal scrollbar appears in the scrollpane. * The options are:<ul> * <li><code>ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED</code> * <li><code>ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER</code> * <li><code>ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS</code> * </ul> * * @param policy one of the three values listed above * @exception IllegalArgumentException if <code>policy</code> * is not one of the legal values shown above * @see #getHorizontalScrollBarPolicy */
@BeanProperty(preferred = true, enumerationValues = { "ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED", "ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER", "ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS"}, description = "The scrollpane scrollbar policy") public void setHorizontalScrollBarPolicy(int policy) { switch (policy) { case HORIZONTAL_SCROLLBAR_AS_NEEDED: case HORIZONTAL_SCROLLBAR_NEVER: case HORIZONTAL_SCROLLBAR_ALWAYS: break; default: throw new IllegalArgumentException("invalid horizontalScrollBarPolicy"); } int old = horizontalScrollBarPolicy; horizontalScrollBarPolicy = policy; firePropertyChange("horizontalScrollBarPolicy", old, policy); revalidate(); repaint(); }
Returns the Border object that surrounds the viewport.
See Also:
Returns:the viewportBorder property
/** * Returns the <code>Border</code> object that surrounds the viewport. * * @return the <code>viewportBorder</code> property * @see #setViewportBorder */
public Border getViewportBorder() { return viewportBorder; }
Adds a border around the viewport. Note that the border isn't set on the viewport directly, JViewport doesn't support the JComponent border property. Similarly setting the JScrollPanes viewport doesn't affect the viewportBorder property.

The default value of this property is computed by the look and feel implementation.

Params:
  • viewportBorder – the border to be added
See Also:
/** * Adds a border around the viewport. Note that the border isn't * set on the viewport directly, <code>JViewport</code> doesn't support * the <code>JComponent</code> border property. * Similarly setting the <code>JScrollPane</code>s * viewport doesn't affect the <code>viewportBorder</code> property. * <p> * The default value of this property is computed by the look * and feel implementation. * * @param viewportBorder the border to be added * @see #getViewportBorder * @see #setViewport */
@BeanProperty(preferred = true, description = "The border around the viewport.") public void setViewportBorder(Border viewportBorder) { Border oldValue = this.viewportBorder; this.viewportBorder = viewportBorder; firePropertyChange("viewportBorder", oldValue, viewportBorder); }
Returns the bounds of the viewport's border.
Returns:a Rectangle object specifying the viewport border
/** * Returns the bounds of the viewport's border. * * @return a <code>Rectangle</code> object specifying the viewport border */
@BeanProperty(bound = false) public Rectangle getViewportBorderBounds() { Rectangle borderR = new Rectangle(getSize()); Insets insets = getInsets(); borderR.x = insets.left; borderR.y = insets.top; borderR.width -= insets.left + insets.right; borderR.height -= insets.top + insets.bottom; boolean leftToRight = SwingUtilities.isLeftToRight(this); /* If there's a visible column header remove the space it * needs from the top of borderR. */ JViewport colHead = getColumnHeader(); if ((colHead != null) && (colHead.isVisible())) { int colHeadHeight = colHead.getHeight(); borderR.y += colHeadHeight; borderR.height -= colHeadHeight; } /* If there's a visible row header remove the space it needs * from the left of borderR. */ JViewport rowHead = getRowHeader(); if ((rowHead != null) && (rowHead.isVisible())) { int rowHeadWidth = rowHead.getWidth(); if ( leftToRight ) { borderR.x += rowHeadWidth; } borderR.width -= rowHeadWidth; } /* If there's a visible vertical scrollbar remove the space it needs * from the width of borderR. */ JScrollBar vsb = getVerticalScrollBar(); if ((vsb != null) && (vsb.isVisible())) { int vsbWidth = vsb.getWidth(); if ( !leftToRight ) { borderR.x += vsbWidth; } borderR.width -= vsbWidth; } /* If there's a visible horizontal scrollbar remove the space it needs * from the height of borderR. */ JScrollBar hsb = getHorizontalScrollBar(); if ((hsb != null) && (hsb.isVisible())) { borderR.height -= hsb.getHeight(); } return borderR; }
By default JScrollPane creates scrollbars that are instances of this class. Scrollbar overrides the getUnitIncrement and getBlockIncrement methods so that, if the viewport's view is a Scrollable, the view is asked to compute these values. Unless the unit/block increment have been explicitly set.

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 applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans™ has been added to the java.beans package. Please see XMLEncoder.

See Also:
/** * By default <code>JScrollPane</code> creates scrollbars * that are instances * of this class. <code>Scrollbar</code> overrides the * <code>getUnitIncrement</code> and <code>getBlockIncrement</code> * methods so that, if the viewport's view is a <code>Scrollable</code>, * the view is asked to compute these values. Unless * the unit/block increment have been explicitly set. * <p> * <strong>Warning:</strong> * 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 applications running * the same version of Swing. As of 1.4, support for long term storage * of all JavaBeans&trade; * has been added to the <code>java.beans</code> package. * Please see {@link java.beans.XMLEncoder}. * * @see Scrollable * @see JScrollPane#createVerticalScrollBar * @see JScrollPane#createHorizontalScrollBar */
@SuppressWarnings("serial") // Same-version serialization only protected class ScrollBar extends JScrollBar implements UIResource {
Set to true when the unit increment has been explicitly set. If this is false the viewport's view is obtained and if it is an instance of Scrollable the unit increment from it is used.
/** * Set to true when the unit increment has been explicitly set. * If this is false the viewport's view is obtained and if it * is an instance of <code>Scrollable</code> the unit increment * from it is used. */
private boolean unitIncrementSet;
Set to true when the block increment has been explicitly set. If this is false the viewport's view is obtained and if it is an instance of Scrollable the block increment from it is used.
/** * Set to true when the block increment has been explicitly set. * If this is false the viewport's view is obtained and if it * is an instance of <code>Scrollable</code> the block increment * from it is used. */
private boolean blockIncrementSet;
Creates a scrollbar with the specified orientation. The options are:
  • ScrollPaneConstants.VERTICAL
  • ScrollPaneConstants.HORIZONTAL
Params:
  • orientation – an integer specifying one of the legal orientation values shown above
Since:1.4
/** * Creates a scrollbar with the specified orientation. * The options are: * <ul> * <li><code>ScrollPaneConstants.VERTICAL</code> * <li><code>ScrollPaneConstants.HORIZONTAL</code> * </ul> * * @param orientation an integer specifying one of the legal * orientation values shown above * @since 1.4 */
public ScrollBar(int orientation) { super(orientation); this.putClientProperty("JScrollBar.fastWheelScrolling", Boolean.TRUE); }
Messages super to set the value, and resets the unitIncrementSet instance variable to true.
Params:
  • unitIncrement – the new unit increment value, in pixels
/** * Messages super to set the value, and resets the * <code>unitIncrementSet</code> instance variable to true. * * @param unitIncrement the new unit increment value, in pixels */
public void setUnitIncrement(int unitIncrement) { unitIncrementSet = true; this.putClientProperty("JScrollBar.fastWheelScrolling", null); super.setUnitIncrement(unitIncrement); }
Computes the unit increment for scrolling if the viewport's view is a Scrollable object. Otherwise return super.getUnitIncrement.
Params:
  • direction – less than zero to scroll up/left, greater than zero for down/right
See Also:
Returns:an integer, in pixels, containing the unit increment
/** * Computes the unit increment for scrolling if the viewport's * view is a <code>Scrollable</code> object. * Otherwise return <code>super.getUnitIncrement</code>. * * @param direction less than zero to scroll up/left, * greater than zero for down/right * @return an integer, in pixels, containing the unit increment * @see Scrollable#getScrollableUnitIncrement */
public int getUnitIncrement(int direction) { JViewport vp = getViewport(); if (!unitIncrementSet && (vp != null) && (vp.getView() instanceof Scrollable)) { Scrollable view = (Scrollable)(vp.getView()); Rectangle vr = vp.getViewRect(); return view.getScrollableUnitIncrement(vr, getOrientation(), direction); } else { return super.getUnitIncrement(direction); } }
Messages super to set the value, and resets the blockIncrementSet instance variable to true.
Params:
  • blockIncrement – the new block increment value, in pixels
/** * Messages super to set the value, and resets the * <code>blockIncrementSet</code> instance variable to true. * * @param blockIncrement the new block increment value, in pixels */
public void setBlockIncrement(int blockIncrement) { blockIncrementSet = true; this.putClientProperty("JScrollBar.fastWheelScrolling", null); super.setBlockIncrement(blockIncrement); }
Computes the block increment for scrolling if the viewport's view is a Scrollable object. Otherwise the blockIncrement equals the viewport's width or height. If there's no viewport return super.getBlockIncrement.
Params:
  • direction – less than zero to scroll up/left, greater than zero for down/right
See Also:
Returns:an integer, in pixels, containing the block increment
/** * Computes the block increment for scrolling if the viewport's * view is a <code>Scrollable</code> object. Otherwise * the <code>blockIncrement</code> equals the viewport's width * or height. If there's no viewport return * <code>super.getBlockIncrement</code>. * * @param direction less than zero to scroll up/left, * greater than zero for down/right * @return an integer, in pixels, containing the block increment * @see Scrollable#getScrollableBlockIncrement */
public int getBlockIncrement(int direction) { JViewport vp = getViewport(); if (blockIncrementSet || vp == null) { return super.getBlockIncrement(direction); } else if (vp.getView() instanceof Scrollable) { Scrollable view = (Scrollable)(vp.getView()); Rectangle vr = vp.getViewRect(); return view.getScrollableBlockIncrement(vr, getOrientation(), direction); } else if (getOrientation() == VERTICAL) { return vp.getExtentSize().height; } else { return vp.getExtentSize().width; } } }
Returns a JScrollPane.ScrollBar by default. Subclasses may override this method to force ScrollPaneUI implementations to use a JScrollBar subclass. Used by ScrollPaneUI implementations to create the horizontal scrollbar.
See Also:
Returns:a JScrollBar with a horizontal orientation
/** * Returns a <code>JScrollPane.ScrollBar</code> by default. * Subclasses may override this method to force <code>ScrollPaneUI</code> * implementations to use a <code>JScrollBar</code> subclass. * Used by <code>ScrollPaneUI</code> implementations to * create the horizontal scrollbar. * * @return a <code>JScrollBar</code> with a horizontal orientation * @see JScrollBar */
public JScrollBar createHorizontalScrollBar() { return new ScrollBar(JScrollBar.HORIZONTAL); }
Returns the horizontal scroll bar that controls the viewport's horizontal view position.
See Also:
Returns:the horizontalScrollBar property
/** * Returns the horizontal scroll bar that controls the viewport's * horizontal view position. * * @return the <code>horizontalScrollBar</code> property * @see #setHorizontalScrollBar */
@Transient public JScrollBar getHorizontalScrollBar() { return horizontalScrollBar; }
Adds the scrollbar that controls the viewport's horizontal view position to the scrollpane. This is usually unnecessary, as JScrollPane creates horizontal and vertical scrollbars by default.
Params:
  • horizontalScrollBar – the horizontal scrollbar to be added
See Also:
/** * Adds the scrollbar that controls the viewport's horizontal view * position to the scrollpane. * This is usually unnecessary, as <code>JScrollPane</code> creates * horizontal and vertical scrollbars by default. * * @param horizontalScrollBar the horizontal scrollbar to be added * @see #createHorizontalScrollBar * @see #getHorizontalScrollBar */
@BeanProperty(expert = true, description = "The horizontal scrollbar.") public void setHorizontalScrollBar(JScrollBar horizontalScrollBar) { JScrollBar old = getHorizontalScrollBar(); this.horizontalScrollBar = horizontalScrollBar; if (horizontalScrollBar != null) { add(horizontalScrollBar, HORIZONTAL_SCROLLBAR); } else if (old != null) { remove(old); } firePropertyChange("horizontalScrollBar", old, horizontalScrollBar); revalidate(); repaint(); }
Returns a JScrollPane.ScrollBar by default. Subclasses may override this method to force ScrollPaneUI implementations to use a JScrollBar subclass. Used by ScrollPaneUI implementations to create the vertical scrollbar.
See Also:
Returns:a JScrollBar with a vertical orientation
/** * Returns a <code>JScrollPane.ScrollBar</code> by default. Subclasses * may override this method to force <code>ScrollPaneUI</code> * implementations to use a <code>JScrollBar</code> subclass. * Used by <code>ScrollPaneUI</code> implementations to create the * vertical scrollbar. * * @return a <code>JScrollBar</code> with a vertical orientation * @see JScrollBar */
public JScrollBar createVerticalScrollBar() { return new ScrollBar(JScrollBar.VERTICAL); }
Returns the vertical scroll bar that controls the viewports vertical view position.
See Also:
Returns:the verticalScrollBar property
/** * Returns the vertical scroll bar that controls the viewports * vertical view position. * * @return the <code>verticalScrollBar</code> property * @see #setVerticalScrollBar */
@Transient public JScrollBar getVerticalScrollBar() { return verticalScrollBar; }
Adds the scrollbar that controls the viewports vertical view position to the scrollpane. This is usually unnecessary, as JScrollPane creates vertical and horizontal scrollbars by default.
Params:
  • verticalScrollBar – the new vertical scrollbar to be added
See Also:
/** * Adds the scrollbar that controls the viewports vertical view position * to the scrollpane. This is usually unnecessary, * as <code>JScrollPane</code> creates vertical and * horizontal scrollbars by default. * * @param verticalScrollBar the new vertical scrollbar to be added * @see #createVerticalScrollBar * @see #getVerticalScrollBar */
@BeanProperty(expert = true, description = "The vertical scrollbar.") public void setVerticalScrollBar(JScrollBar verticalScrollBar) { JScrollBar old = getVerticalScrollBar(); this.verticalScrollBar = verticalScrollBar; add(verticalScrollBar, VERTICAL_SCROLLBAR); firePropertyChange("verticalScrollBar", old, verticalScrollBar); revalidate(); repaint(); }
Returns a new JViewport by default. Used to create the viewport (as needed) in setViewportView, setRowHeaderView, and setColumnHeaderView. Subclasses may override this method to return a subclass of JViewport.
Returns:a new JViewport
/** * Returns a new <code>JViewport</code> by default. * Used to create the * viewport (as needed) in <code>setViewportView</code>, * <code>setRowHeaderView</code>, and <code>setColumnHeaderView</code>. * Subclasses may override this method to return a subclass of * <code>JViewport</code>. * * @return a new <code>JViewport</code> */
protected JViewport createViewport() { return new JViewport(); }
Returns the current JViewport.
See Also:
  • setViewport
Returns:the viewport property
/** * Returns the current <code>JViewport</code>. * * @see #setViewport * @return the <code>viewport</code> property */
public JViewport getViewport() { return viewport; }
Removes the old viewport (if there is one); forces the viewPosition of the new viewport to be in the +x,+y quadrant; syncs up the row and column headers (if there are any) with the new viewport; and finally syncs the scrollbars and headers with the new viewport.

Most applications will find it more convenient to use setViewportView to add a viewport and a view to the scrollpane.

Params:
  • viewport – the new viewport to be used; if viewport is null, the old viewport is still removed and the new viewport is set to null
See Also:
/** * Removes the old viewport (if there is one); forces the * viewPosition of the new viewport to be in the +x,+y quadrant; * syncs up the row and column headers (if there are any) with the * new viewport; and finally syncs the scrollbars and * headers with the new viewport. * <p> * Most applications will find it more convenient to use * <code>setViewportView</code> * to add a viewport and a view to the scrollpane. * * @param viewport the new viewport to be used; if viewport is * <code>null</code>, the old viewport is still removed * and the new viewport is set to <code>null</code> * @see #createViewport * @see #getViewport * @see #setViewportView */
@BeanProperty(expert = true, visualUpdate = true, description = "The viewport child for this scrollpane") public void setViewport(JViewport viewport) { JViewport old = getViewport(); this.viewport = viewport; if (viewport != null) { add(viewport, VIEWPORT); } else if (old != null) { remove(old); } firePropertyChange("viewport", old, viewport); if (accessibleContext != null) { ((AccessibleJScrollPane)accessibleContext).resetViewPort(); } revalidate(); repaint(); }
Creates a viewport if necessary and then sets its view. Applications that don't provide the view directly to the JScrollPane constructor should use this method to specify the scrollable child that's going to be displayed in the scrollpane. For example:
JScrollPane scrollpane = new JScrollPane();
scrollpane.setViewportView(myBigComponentToScroll);
Applications should not add children directly to the scrollpane.
Params:
  • view – the component to add to the viewport
See Also:
/** * Creates a viewport if necessary and then sets its view. Applications * that don't provide the view directly to the <code>JScrollPane</code> * constructor * should use this method to specify the scrollable child that's going * to be displayed in the scrollpane. For example: * <pre> * JScrollPane scrollpane = new JScrollPane(); * scrollpane.setViewportView(myBigComponentToScroll); * </pre> * Applications should not add children directly to the scrollpane. * * @param view the component to add to the viewport * @see #setViewport * @see JViewport#setView */
public void setViewportView(Component view) { if (getViewport() == null) { setViewport(createViewport()); } getViewport().setView(view); }
Returns the row header.
See Also:
Returns:the rowHeader property
/** * Returns the row header. * @return the <code>rowHeader</code> property * @see #setRowHeader */
@Transient public JViewport getRowHeader() { return rowHeader; }
Removes the old rowHeader, if it exists; if the new rowHeader isn't null, syncs the y coordinate of its viewPosition with the viewport (if there is one) and then adds it to the scroll pane.

Most applications will find it more convenient to use setRowHeaderView to add a row header component and its viewport to the scroll pane.

Params:
  • rowHeader – the new row header to be used; if null the old row header is still removed and the new rowHeader is set to null
See Also:
/** * Removes the old rowHeader, if it exists; if the new rowHeader * isn't <code>null</code>, syncs the y coordinate of its * viewPosition with * the viewport (if there is one) and then adds it to the scroll pane. * <p> * Most applications will find it more convenient to use * <code>setRowHeaderView</code> * to add a row header component and its viewport to the scroll pane. * * @param rowHeader the new row header to be used; if <code>null</code> * the old row header is still removed and the new rowHeader * is set to <code>null</code> * @see #getRowHeader * @see #setRowHeaderView */
@BeanProperty(expert = true, description = "The row header child for this scrollpane") public void setRowHeader(JViewport rowHeader) { JViewport old = getRowHeader(); this.rowHeader = rowHeader; if (rowHeader != null) { add(rowHeader, ROW_HEADER); } else if (old != null) { remove(old); } firePropertyChange("rowHeader", old, rowHeader); revalidate(); repaint(); }
Creates a row-header viewport if necessary, sets its view and then adds the row-header viewport to the scrollpane. For example:
JScrollPane scrollpane = new JScrollPane();
scrollpane.setViewportView(myBigComponentToScroll);
scrollpane.setRowHeaderView(myBigComponentsRowHeader);
Params:
  • view – the component to display as the row header
See Also:
/** * Creates a row-header viewport if necessary, sets * its view and then adds the row-header viewport * to the scrollpane. For example: * <pre> * JScrollPane scrollpane = new JScrollPane(); * scrollpane.setViewportView(myBigComponentToScroll); * scrollpane.setRowHeaderView(myBigComponentsRowHeader); * </pre> * * @see #setRowHeader * @see JViewport#setView * @param view the component to display as the row header */
public void setRowHeaderView(Component view) { if (getRowHeader() == null) { setRowHeader(createViewport()); } getRowHeader().setView(view); }
Returns the column header.
See Also:
Returns:the columnHeader property
/** * Returns the column header. * @return the <code>columnHeader</code> property * @see #setColumnHeader */
@Transient public JViewport getColumnHeader() { return columnHeader; }
Removes the old columnHeader, if it exists; if the new columnHeader isn't null, syncs the x coordinate of its viewPosition with the viewport (if there is one) and then adds it to the scroll pane.

Most applications will find it more convenient to use setColumnHeaderView to add a column header component and its viewport to the scroll pane.

Params:
  • columnHeader – a JViewport which is the new column header
See Also:
/** * Removes the old columnHeader, if it exists; if the new columnHeader * isn't <code>null</code>, syncs the x coordinate of its viewPosition * with the viewport (if there is one) and then adds it to the scroll pane. * <p> * Most applications will find it more convenient to use * <code>setColumnHeaderView</code> * to add a column header component and its viewport to the scroll pane. * * @param columnHeader a {@code JViewport} which is the new column header * @see #getColumnHeader * @see #setColumnHeaderView */
@BeanProperty(visualUpdate = true, description = "The column header child for this scrollpane") public void setColumnHeader(JViewport columnHeader) { JViewport old = getColumnHeader(); this.columnHeader = columnHeader; if (columnHeader != null) { add(columnHeader, COLUMN_HEADER); } else if (old != null) { remove(old); } firePropertyChange("columnHeader", old, columnHeader); revalidate(); repaint(); }
Creates a column-header viewport if necessary, sets its view, and then adds the column-header viewport to the scrollpane. For example:
JScrollPane scrollpane = new JScrollPane();
scrollpane.setViewportView(myBigComponentToScroll);
scrollpane.setColumnHeaderView(myBigComponentsColumnHeader);
Params:
  • view – the component to display as the column header
See Also:
/** * Creates a column-header viewport if necessary, sets * its view, and then adds the column-header viewport * to the scrollpane. For example: * <pre> * JScrollPane scrollpane = new JScrollPane(); * scrollpane.setViewportView(myBigComponentToScroll); * scrollpane.setColumnHeaderView(myBigComponentsColumnHeader); * </pre> * * @see #setColumnHeader * @see JViewport#setView * * @param view the component to display as the column header */
public void setColumnHeaderView(Component view) { if (getColumnHeader() == null) { setColumnHeader(createViewport()); } getColumnHeader().setView(view); }
Returns the component at the specified corner. The key value specifying the corner is one of:
  • ScrollPaneConstants.LOWER_LEFT_CORNER
  • ScrollPaneConstants.LOWER_RIGHT_CORNER
  • ScrollPaneConstants.UPPER_LEFT_CORNER
  • ScrollPaneConstants.UPPER_RIGHT_CORNER
  • ScrollPaneConstants.LOWER_LEADING_CORNER
  • ScrollPaneConstants.LOWER_TRAILING_CORNER
  • ScrollPaneConstants.UPPER_LEADING_CORNER
  • ScrollPaneConstants.UPPER_TRAILING_CORNER
Params:
  • key – one of the values as shown above
See Also:
Returns:the corner component (which may be null) identified by the given key, or null if the key is invalid
/** * Returns the component at the specified corner. The * <code>key</code> value specifying the corner is one of: * <ul> * <li>ScrollPaneConstants.LOWER_LEFT_CORNER * <li>ScrollPaneConstants.LOWER_RIGHT_CORNER * <li>ScrollPaneConstants.UPPER_LEFT_CORNER * <li>ScrollPaneConstants.UPPER_RIGHT_CORNER * <li>ScrollPaneConstants.LOWER_LEADING_CORNER * <li>ScrollPaneConstants.LOWER_TRAILING_CORNER * <li>ScrollPaneConstants.UPPER_LEADING_CORNER * <li>ScrollPaneConstants.UPPER_TRAILING_CORNER * </ul> * * @param key one of the values as shown above * @return the corner component (which may be <code>null</code>) * identified by the given key, or <code>null</code> * if the key is invalid * @see #setCorner */
public Component getCorner(String key) { boolean isLeftToRight = getComponentOrientation().isLeftToRight(); if (key.equals(LOWER_LEADING_CORNER)) { key = isLeftToRight ? LOWER_LEFT_CORNER : LOWER_RIGHT_CORNER; } else if (key.equals(LOWER_TRAILING_CORNER)) { key = isLeftToRight ? LOWER_RIGHT_CORNER : LOWER_LEFT_CORNER; } else if (key.equals(UPPER_LEADING_CORNER)) { key = isLeftToRight ? UPPER_LEFT_CORNER : UPPER_RIGHT_CORNER; } else if (key.equals(UPPER_TRAILING_CORNER)) { key = isLeftToRight ? UPPER_RIGHT_CORNER : UPPER_LEFT_CORNER; } if (key.equals(LOWER_LEFT_CORNER)) { return lowerLeft; } else if (key.equals(LOWER_RIGHT_CORNER)) { return lowerRight; } else if (key.equals(UPPER_LEFT_CORNER)) { return upperLeft; } else if (key.equals(UPPER_RIGHT_CORNER)) { return upperRight; } else { return null; } }
Adds a child that will appear in one of the scroll panes corners, if there's room. For example with both scrollbars showing (on the right and bottom edges of the scrollpane) the lower left corner component will be shown in the space between ends of the two scrollbars. Legal values for the key are:
  • ScrollPaneConstants.LOWER_LEFT_CORNER
  • ScrollPaneConstants.LOWER_RIGHT_CORNER
  • ScrollPaneConstants.UPPER_LEFT_CORNER
  • ScrollPaneConstants.UPPER_RIGHT_CORNER
  • ScrollPaneConstants.LOWER_LEADING_CORNER
  • ScrollPaneConstants.LOWER_TRAILING_CORNER
  • ScrollPaneConstants.UPPER_LEADING_CORNER
  • ScrollPaneConstants.UPPER_TRAILING_CORNER

Although "corner" doesn't match any beans property signature, PropertyChange events are generated with the property name set to the corner key.

Params:
  • key – identifies which corner the component will appear in
  • corner – one of the following components:
    • lowerLeft
    • lowerRight
    • upperLeft
    • upperRight
Throws:
/** * Adds a child that will appear in one of the scroll panes * corners, if there's room. For example with both scrollbars * showing (on the right and bottom edges of the scrollpane) * the lower left corner component will be shown in the space * between ends of the two scrollbars. Legal values for * the <b>key</b> are: * <ul> * <li>ScrollPaneConstants.LOWER_LEFT_CORNER * <li>ScrollPaneConstants.LOWER_RIGHT_CORNER * <li>ScrollPaneConstants.UPPER_LEFT_CORNER * <li>ScrollPaneConstants.UPPER_RIGHT_CORNER * <li>ScrollPaneConstants.LOWER_LEADING_CORNER * <li>ScrollPaneConstants.LOWER_TRAILING_CORNER * <li>ScrollPaneConstants.UPPER_LEADING_CORNER * <li>ScrollPaneConstants.UPPER_TRAILING_CORNER * </ul> * <p> * Although "corner" doesn't match any beans property * signature, <code>PropertyChange</code> events are generated with the * property name set to the corner key. * * @param key identifies which corner the component will appear in * @param corner one of the following components: * <ul> * <li>lowerLeft * <li>lowerRight * <li>upperLeft * <li>upperRight * </ul> * @exception IllegalArgumentException if corner key is invalid */
public void setCorner(String key, Component corner) { Component old; boolean isLeftToRight = getComponentOrientation().isLeftToRight(); if (key.equals(LOWER_LEADING_CORNER)) { key = isLeftToRight ? LOWER_LEFT_CORNER : LOWER_RIGHT_CORNER; } else if (key.equals(LOWER_TRAILING_CORNER)) { key = isLeftToRight ? LOWER_RIGHT_CORNER : LOWER_LEFT_CORNER; } else if (key.equals(UPPER_LEADING_CORNER)) { key = isLeftToRight ? UPPER_LEFT_CORNER : UPPER_RIGHT_CORNER; } else if (key.equals(UPPER_TRAILING_CORNER)) { key = isLeftToRight ? UPPER_RIGHT_CORNER : UPPER_LEFT_CORNER; } if (key.equals(LOWER_LEFT_CORNER)) { old = lowerLeft; lowerLeft = corner; } else if (key.equals(LOWER_RIGHT_CORNER)) { old = lowerRight; lowerRight = corner; } else if (key.equals(UPPER_LEFT_CORNER)) { old = upperLeft; upperLeft = corner; } else if (key.equals(UPPER_RIGHT_CORNER)) { old = upperRight; upperRight = corner; } else { throw new IllegalArgumentException("invalid corner key"); } if (old != null) { remove(old); } if (corner != null) { add(corner, key); } firePropertyChange(key, old, corner); revalidate(); repaint(); }
Sets the orientation for the vertical and horizontal scrollbars as determined by the ComponentOrientation argument.
Params:
  • co – one of the following values:
    • java.awt.ComponentOrientation.LEFT_TO_RIGHT
    • java.awt.ComponentOrientation.RIGHT_TO_LEFT
    • java.awt.ComponentOrientation.UNKNOWN
See Also:
/** * Sets the orientation for the vertical and horizontal * scrollbars as determined by the * <code>ComponentOrientation</code> argument. * * @param co one of the following values: * <ul> * <li>java.awt.ComponentOrientation.LEFT_TO_RIGHT * <li>java.awt.ComponentOrientation.RIGHT_TO_LEFT * <li>java.awt.ComponentOrientation.UNKNOWN * </ul> * @see java.awt.ComponentOrientation */
public void setComponentOrientation( ComponentOrientation co ) { super.setComponentOrientation( co ); if( verticalScrollBar != null ) verticalScrollBar.setComponentOrientation( co ); if( horizontalScrollBar != null ) horizontalScrollBar.setComponentOrientation( co ); }
Indicates whether or not scrolling will take place in response to the mouse wheel. Wheel scrolling is enabled by default.
See Also:
Returns:true if mouse wheel scrolling is enabled, false otherwise
Since:1.4
/** * Indicates whether or not scrolling will take place in response to the * mouse wheel. Wheel scrolling is enabled by default. * * @return true if mouse wheel scrolling is enabled, false otherwise * @see #setWheelScrollingEnabled * @since 1.4 */
@BeanProperty(description = "Flag for enabling/disabling mouse wheel scrolling") public boolean isWheelScrollingEnabled() {return wheelScrollState;}
Enables/disables scrolling in response to movement of the mouse wheel. Wheel scrolling is enabled by default.
Params:
  • handleWheel – true if scrolling should be done automatically for a MouseWheelEvent, false otherwise.
See Also:
Since:1.4
/** * Enables/disables scrolling in response to movement of the mouse wheel. * Wheel scrolling is enabled by default. * * @param handleWheel <code>true</code> if scrolling should be done * automatically for a MouseWheelEvent, * <code>false</code> otherwise. * @see #isWheelScrollingEnabled * @see java.awt.event.MouseWheelEvent * @see java.awt.event.MouseWheelListener * @since 1.4 */
@BeanProperty(description = "Flag for enabling/disabling mouse wheel scrolling") public void setWheelScrollingEnabled(boolean handleWheel) { boolean old = wheelScrollState; wheelScrollState = handleWheel; firePropertyChange("wheelScrollingEnabled", old, handleWheel); }
See readObject and writeObject in JComponent for more information about serialization in Swing.
/** * See <code>readObject</code> and <code>writeObject</code> in * <code>JComponent</code> for more * information about serialization in Swing. */
private void writeObject(ObjectOutputStream s) throws IOException { s.defaultWriteObject(); if (getUIClassID().equals(uiClassID)) { byte count = JComponent.getWriteObjCounter(this); JComponent.setWriteObjCounter(this, --count); if (count == 0 && ui != null) { ui.installUI(this); } } }
Returns a string representation of this JScrollPane. This method is intended to be used only for debugging purposes, and the content and format of the returned string may vary between implementations. The returned string may be empty but may not be null.
Returns: a string representation of this JScrollPane.
/** * Returns a string representation of this <code>JScrollPane</code>. * This method * is intended to be used only for debugging purposes, and the * content and format of the returned string may vary between * implementations. The returned string may be empty but may not * be <code>null</code>. * * @return a string representation of this <code>JScrollPane</code>. */
protected String paramString() { String viewportBorderString = (viewportBorder != null ? viewportBorder.toString() : ""); String viewportString = (viewport != null ? viewport.toString() : ""); String verticalScrollBarPolicyString; if (verticalScrollBarPolicy == VERTICAL_SCROLLBAR_AS_NEEDED) { verticalScrollBarPolicyString = "VERTICAL_SCROLLBAR_AS_NEEDED"; } else if (verticalScrollBarPolicy == VERTICAL_SCROLLBAR_NEVER) { verticalScrollBarPolicyString = "VERTICAL_SCROLLBAR_NEVER"; } else if (verticalScrollBarPolicy == VERTICAL_SCROLLBAR_ALWAYS) { verticalScrollBarPolicyString = "VERTICAL_SCROLLBAR_ALWAYS"; } else verticalScrollBarPolicyString = ""; String horizontalScrollBarPolicyString; if (horizontalScrollBarPolicy == HORIZONTAL_SCROLLBAR_AS_NEEDED) { horizontalScrollBarPolicyString = "HORIZONTAL_SCROLLBAR_AS_NEEDED"; } else if (horizontalScrollBarPolicy == HORIZONTAL_SCROLLBAR_NEVER) { horizontalScrollBarPolicyString = "HORIZONTAL_SCROLLBAR_NEVER"; } else if (horizontalScrollBarPolicy == HORIZONTAL_SCROLLBAR_ALWAYS) { horizontalScrollBarPolicyString = "HORIZONTAL_SCROLLBAR_ALWAYS"; } else horizontalScrollBarPolicyString = ""; String horizontalScrollBarString = (horizontalScrollBar != null ? horizontalScrollBar.toString() : ""); String verticalScrollBarString = (verticalScrollBar != null ? verticalScrollBar.toString() : ""); String columnHeaderString = (columnHeader != null ? columnHeader.toString() : ""); String rowHeaderString = (rowHeader != null ? rowHeader.toString() : ""); String lowerLeftString = (lowerLeft != null ? lowerLeft.toString() : ""); String lowerRightString = (lowerRight != null ? lowerRight.toString() : ""); String upperLeftString = (upperLeft != null ? upperLeft.toString() : ""); String upperRightString = (upperRight != null ? upperRight.toString() : ""); return super.paramString() + ",columnHeader=" + columnHeaderString + ",horizontalScrollBar=" + horizontalScrollBarString + ",horizontalScrollBarPolicy=" + horizontalScrollBarPolicyString + ",lowerLeft=" + lowerLeftString + ",lowerRight=" + lowerRightString + ",rowHeader=" + rowHeaderString + ",upperLeft=" + upperLeftString + ",upperRight=" + upperRightString + ",verticalScrollBar=" + verticalScrollBarString + ",verticalScrollBarPolicy=" + verticalScrollBarPolicyString + ",viewport=" + viewportString + ",viewportBorder=" + viewportBorderString; } ///////////////// // Accessibility support ////////////////
Gets the AccessibleContext associated with this JScrollPane. For scroll panes, the AccessibleContext takes the form of an AccessibleJScrollPane. A new AccessibleJScrollPane instance is created if necessary.
Returns:an AccessibleJScrollPane that serves as the AccessibleContext of this JScrollPane
/** * Gets the AccessibleContext associated with this JScrollPane. * For scroll panes, the AccessibleContext takes the form of an * AccessibleJScrollPane. * A new AccessibleJScrollPane instance is created if necessary. * * @return an AccessibleJScrollPane that serves as the * AccessibleContext of this JScrollPane */
@BeanProperty(bound = false) public AccessibleContext getAccessibleContext() { if (accessibleContext == null) { accessibleContext = new AccessibleJScrollPane(); } return accessibleContext; }
This class implements accessibility support for the JScrollPane class. It provides an implementation of the Java Accessibility API appropriate to scroll pane user-interface elements.

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 applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans™ has been added to the java.beans package. Please see XMLEncoder.

/** * This class implements accessibility support for the * <code>JScrollPane</code> class. It provides an implementation of the * Java Accessibility API appropriate to scroll pane user-interface * elements. * <p> * <strong>Warning:</strong> * 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 applications running * the same version of Swing. As of 1.4, support for long term storage * of all JavaBeans&trade; * has been added to the <code>java.beans</code> package. * Please see {@link java.beans.XMLEncoder}. */
@SuppressWarnings("serial") // Same-version serialization only protected class AccessibleJScrollPane extends AccessibleJComponent implements ChangeListener, PropertyChangeListener {
this JScrollPane's current JViewport
/** * this {@code JScrollPane}'s current {@code JViewport} */
protected JViewport viewPort = null;
Resets the viewport ChangeListener and PropertyChangeListener
/** * Resets the viewport ChangeListener and PropertyChangeListener */
public void resetViewPort() { if (viewPort != null) { viewPort.removeChangeListener(this); viewPort.removePropertyChangeListener(this); } viewPort = JScrollPane.this.getViewport(); if (viewPort != null) { viewPort.addChangeListener(this); viewPort.addPropertyChangeListener(this); } }
AccessibleJScrollPane constructor
/** * AccessibleJScrollPane constructor */
public AccessibleJScrollPane() { super(); resetViewPort(); // initialize the AccessibleRelationSets for the JScrollPane // and JScrollBar(s) JScrollBar scrollBar = getHorizontalScrollBar(); if (scrollBar != null) { setScrollBarRelations(scrollBar); } scrollBar = getVerticalScrollBar(); if (scrollBar != null) { setScrollBarRelations(scrollBar); } }
Get the role of this object.
See Also:
Returns:an instance of AccessibleRole describing the role of the object
/** * Get the role of this object. * * @return an instance of AccessibleRole describing the role of the * object * @see AccessibleRole */
public AccessibleRole getAccessibleRole() { return AccessibleRole.SCROLL_PANE; }
Invoked when the target of the listener has changed its state.
Params:
  • e – a ChangeEvent object. Must not be null.
Throws:
/** * Invoked when the target of the listener has changed its state. * * @param e a <code>ChangeEvent</code> object. Must not be null. * * @throws NullPointerException if the parameter is null. */
public void stateChanged(ChangeEvent e) { if (e == null) { throw new NullPointerException(); } firePropertyChange(ACCESSIBLE_VISIBLE_DATA_PROPERTY, Boolean.valueOf(false), Boolean.valueOf(true)); }
This method gets called when a bound property is changed.
Params:
  • e – A PropertyChangeEvent object describing the event source and the property that has changed. Must not be null.
Throws:
Since:1.5
/** * This method gets called when a bound property is changed. * @param e A <code>PropertyChangeEvent</code> object describing * the event source and the property that has changed. Must not be null. * * @throws NullPointerException if the parameter is null. * @since 1.5 */
public void propertyChange(PropertyChangeEvent e) { String propertyName = e.getPropertyName(); if (propertyName == "horizontalScrollBar" || propertyName == "verticalScrollBar") { if (e.getNewValue() instanceof JScrollBar) { setScrollBarRelations((JScrollBar)e.getNewValue()); } } } /* * Sets the CONTROLLER_FOR and CONTROLLED_BY AccessibleRelations for * the JScrollPane and JScrollBar. JScrollBar must not be null. */ void setScrollBarRelations(JScrollBar scrollBar) { /* * The JScrollBar is a CONTROLLER_FOR the JScrollPane. * The JScrollPane is CONTROLLED_BY the JScrollBar. */ AccessibleRelation controlledBy = new AccessibleRelation(AccessibleRelation.CONTROLLED_BY, scrollBar); AccessibleRelation controllerFor = new AccessibleRelation(AccessibleRelation.CONTROLLER_FOR, JScrollPane.this); // set the relation set for the scroll bar AccessibleContext ac = scrollBar.getAccessibleContext(); ac.getAccessibleRelationSet().add(controllerFor); // set the relation set for the scroll pane getAccessibleRelationSet().add(controlledBy); } } }