DefaultTableCellRenderer.java

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packagejavax.swing.table;

importjavax.swing.*;
importjavax.swing.border.*;

importjava.awt.Component;
importjava.awt.Color;
importjava.awt.Rectangle;

importjava.io.Serializable;
importsun.swing.DefaultLookup;
importsun.swing.SwingUtilities2;

/**
 * The standard class for rendering (displaying) individual cells
 * in a <code>JTable</code>.
 * <p>
 *
 * <strong><a id="override">Implementation Note:</a></strong>
 * This class inherits from <code>JLabel</code>, a standard component class.
 * However <code>JTable</code> employs a unique mechanism for rendering
 * its cells and therefore requires some slightly modified behavior
 * from its cell renderer.
 * The table class defines a single cell renderer and uses it as a
 * as a rubber-stamp for rendering all cells in the table;
 * it renders the first cell,
 * changes the contents of that cell renderer,
 * shifts the origin to the new location, re-draws it, and so on.
 * The standard <code>JLabel</code> component was not
 * designed to be used this way and we want to avoid
 * triggering a <code>revalidate</code> each time the
 * cell is drawn. This would greatly decrease performance because the
 * <code>revalidate</code> message would be
 * passed up the hierarchy of the container to determine whether any other
 * components would be affected.
 * As the renderer is only parented for the lifetime of a painting operation
 * we similarly want to avoid the overhead associated with walking the
 * hierarchy for painting operations.
 * So this class
 * overrides the <code>validate</code>, <code>invalidate</code>,
 * <code>revalidate</code>, <code>repaint</code>, and
 * <code>firePropertyChange</code> methods to be
 * no-ops and override the <code>isOpaque</code> method solely to improve
 * performance. If you write your own renderer,
 * please keep this performance consideration in mind.
 * <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
 * has been added to the <code>java.beans</code> package.
 * Please see {@link java.beans.XMLEncoder}.
 *
 * @author Philip Milne
 * @see JTable
 */
@SuppressWarnings("serial") // Same-version serialization only
publicclassDefaultTableCellRendererextendsJLabel
implementsTableCellRenderer, Serializable
{

/**
 * An empty <code>Border</code>. This field might not be used. To change the
 * <code>Border</code> used by this renderer override the
 * <code>getTableCellRendererComponent</code> method and set the border
 * of the returned component directly.
 */
privatestaticfinalBorderDEFAULT_NO_FOCUS_BORDER = newEmptyBorder(1, 1, 1, 1);
/**
 * A border without focus.
 */
protectedstaticBordernoFocusBorder = DEFAULT_NO_FOCUS_BORDER;

// We need a place to store the color the JLabel should be returned
// to after its foreground and background colors have been set
// to the selection background color.
// These ivars will be made protected when their names are finalized.
privateColorunselectedForeground;
privateColorunselectedBackground;

/**
 * Creates a default table cell renderer.
 */
publicDefaultTableCellRenderer() {
super();
setOpaque(true);
setBorder(getNoFocusBorder());
setName("Table.cellRenderer");
 }

privateBordergetNoFocusBorder() {
Borderborder = DefaultLookup.getBorder(this, ui, "Table.cellNoFocusBorder");
if (border != null) {
if (noFocusBorder == null || noFocusBorder == DEFAULT_NO_FOCUS_BORDER) {
returnborder;
 }
 }
returnnoFocusBorder;
 }

/**
 * Overrides <code>JComponent.setForeground</code> to assign
 * the unselected-foreground color to the specified color.
 *
 * @param c set the foreground color to this value
 */
publicvoidsetForeground(Colorc) {
super.setForeground(c);
unselectedForeground = c;
 }

/**
 * Overrides <code>JComponent.setBackground</code> to assign
 * the unselected-background color to the specified color.
 *
 * @param c set the background color to this value
 */
publicvoidsetBackground(Colorc) {
super.setBackground(c);
unselectedBackground = c;
 }

/**
 * Notification from the <code>UIManager</code> that the look and feel
 * [L&amp;F] has changed.
 * Replaces the current UI object with the latest version from the
 * <code>UIManager</code>.
 *
 * @see JComponent#updateUI
 */
publicvoidupdateUI() {
super.updateUI();
setForeground(null);
setBackground(null);
 }

// implements javax.swing.table.TableCellRenderer
/**
 *
 * Returns the default table cell renderer.
 * <p>
 * During a printing operation, this method will be called with
 * <code>isSelected</code> and <code>hasFocus</code> values of
 * <code>false</code> to prevent selection and focus from appearing
 * in the printed output. To do other customization based on whether
 * or not the table is being printed, check the return value from
 * {@link javax.swing.JComponent#isPaintingForPrint()}.
 *
 * @param table the <code>JTable</code>
 * @param value the value to assign to the cell at
 * <code>[row, column]</code>
 * @param isSelected true if cell is selected
 * @param hasFocus true if cell has focus
 * @param row the row of the cell to render
 * @param column the column of the cell to render
 * @return the default table cell renderer
 * @see javax.swing.JComponent#isPaintingForPrint()
 */
publicComponentgetTableCellRendererComponent(JTabletable, Objectvalue,
booleanisSelected, booleanhasFocus, introw, intcolumn) {
if (table == null) {
returnthis;
 }

Colorfg = null;
Colorbg = null;

JTable.DropLocationdropLocation = table.getDropLocation();
if (dropLocation != null
 && !dropLocation.isInsertRow()
 && !dropLocation.isInsertColumn()
 && dropLocation.getRow() == row
 && dropLocation.getColumn() == column) {

fg = DefaultLookup.getColor(this, ui, "Table.dropCellForeground");
bg = DefaultLookup.getColor(this, ui, "Table.dropCellBackground");

isSelected = true;
 }

if (isSelected) {
super.setForeground(fg == null ? table.getSelectionForeground()
 : fg);
super.setBackground(bg == null ? table.getSelectionBackground()
 : bg);
 } else {
Colorbackground = unselectedBackground != null
 ? unselectedBackground
 : table.getBackground();
if (background == null || backgroundinstanceofjavax.swing.plaf.UIResource) {
ColoralternateColor = DefaultLookup.getColor(this, ui, "Table.alternateRowColor");
if (alternateColor != null && row % 2 != 0) {
background = alternateColor;
 }
 }
super.setForeground(unselectedForeground != null
 ? unselectedForeground
 : table.getForeground());
super.setBackground(background);
 }

setFont(table.getFont());

if (hasFocus) {
Borderborder = null;
if (isSelected) {
border = DefaultLookup.getBorder(this, ui, "Table.focusSelectedCellHighlightBorder");
 }
if (border == null) {
border = DefaultLookup.getBorder(this, ui, "Table.focusCellHighlightBorder");
 }
setBorder(border);

if (!isSelected && table.isCellEditable(row, column)) {
Colorcol;
col = DefaultLookup.getColor(this, ui, "Table.focusCellForeground");
if (col != null) {
super.setForeground(col);
 }
col = DefaultLookup.getColor(this, ui, "Table.focusCellBackground");
if (col != null) {
super.setBackground(col);
 }
 }
 } else {
setBorder(getNoFocusBorder());
 }

setValue(value);

returnthis;
 }

/*
 * The following methods are overridden as a performance measure to
 * to prune code-paths are often called in the case of renders
 * but which we know are unnecessary. Great care should be taken
 * when writing your own renderer to weigh the benefits and
 * drawbacks of overriding methods like these.
 */

/**
 * Overridden for performance reasons.
 * See the <a href="#override">Implementation Note</a>
 * for more information.
 */
publicbooleanisOpaque() {
Colorback = getBackground();
Componentp = getParent();
if (p != null) {
p = p.getParent();
 }

// p should now be the JTable.
booleancolorMatch = (back != null) && (p != null) &&
back.equals(p.getBackground()) &&
p.isOpaque();
return !colorMatch && super.isOpaque();
 }

/**
 * Overridden for performance reasons.
 * See the <a href="#override">Implementation Note</a>
 * for more information.
 *
 * @since 1.5
 */
publicvoidinvalidate() {}

/**
 * Overridden for performance reasons.
 * See the <a href="#override">Implementation Note</a>
 * for more information.
 */
publicvoidvalidate() {}

/**
 * Overridden for performance reasons.
 * See the <a href="#override">Implementation Note</a>
 * for more information.
 */
publicvoidrevalidate() {}

/**
 * Overridden for performance reasons.
 * See the <a href="#override">Implementation Note</a>
 * for more information.
 */
publicvoidrepaint(longtm, intx, inty, intwidth, intheight) {}

/**
 * Overridden for performance reasons.
 * See the <a href="#override">Implementation Note</a>
 * for more information.
 */
publicvoidrepaint(Rectangler) { }

/**
 * Overridden for performance reasons.
 * See the <a href="#override">Implementation Note</a>
 * for more information.
 *
 * @since 1.5
 */
publicvoidrepaint() {
 }

/**
 * Overridden for performance reasons.
 * See the <a href="#override">Implementation Note</a>
 * for more information.
 */
protectedvoidfirePropertyChange(StringpropertyName, ObjectoldValue, ObjectnewValue) {
// Strings get interned...
if (propertyName=="text"
 || propertyName == "labelFor"
 || propertyName == "displayedMnemonic"
 || ((SwingUtilities2.isScaleChanged(propertyName, oldValue, newValue)
 || propertyName == "font" || propertyName == "foreground")
 && oldValue != newValue
 && getClientProperty(javax.swing.plaf.basic.BasicHTML.propertyKey) != null)) {

super.firePropertyChange(propertyName, oldValue, newValue);
 }
 }

/**
 * Overridden for performance reasons.
 * See the <a href="#override">Implementation Note</a>
 * for more information.
 */
publicvoidfirePropertyChange(StringpropertyName, booleanoldValue, booleannewValue) { }


/**
 * Sets the <code>String</code> object for the cell being rendered to
 * <code>value</code>.
 *
 * @param value the string value for this cell; if value is
 * <code>null</code> it sets the text value to an empty string
 * @see JLabel#setText
 *
 */
protectedvoidsetValue(Objectvalue) {
setText((value == null) ? "" : value.toString());
 }


/**
 * A subclass of <code>DefaultTableCellRenderer</code> that
 * implements <code>UIResource</code>.
 * <code>DefaultTableCellRenderer</code> doesn't implement
 * <code>UIResource</code>
 * directly so that applications can safely override the
 * <code>cellRenderer</code> property with
 * <code>DefaultTableCellRenderer</code> subclasses.
 * <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
 * has been added to the <code>java.beans</code> package.
 * Please see {@link java.beans.XMLEncoder}.
 */
@SuppressWarnings("serial") // Same-version serialization only
publicstaticclassUIResourceextendsDefaultTableCellRenderer
implementsjavax.swing.plaf.UIResource
 {
/**
 * Constructs a {@code UIResource}.
 */
publicUIResource() {}
 }

}