FileDocCategorySizeDatePackage
DefaultTableCellRenderer.javaAPI DocJava SE 5 API10416Fri Aug 26 14:58:14 BST 2005javax.swing.table

DefaultTableCellRenderer

public class DefaultTableCellRenderer extends JLabel implements TableCellRenderer, Serializable
The standard class for rendering (displaying) individual cells in a JTable.

Implementation Note: This class inherits from JLabel, a standard component class. However JTable 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 JLabel component was not designed to be used this way and we want to avoid triggering a revalidate each time the cell is drawn. This would greatly decrease performance because the revalidate 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 validate, invalidate, revalidate, repaint, and firePropertyChange methods to be no-ops and override the isOpaque method solely to improve performance. If you write your own renderer, please keep this performance consideration in mind.

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 JavaBeansTM has been added to the java.beans package. Please see {@link java.beans.XMLEncoder}.

version
1.40 05/27/05
author
Philip Milne
see
JTable

Fields Summary
protected static Border
noFocusBorder
private Color
unselectedForeground
private Color
unselectedBackground
Constructors Summary
public DefaultTableCellRenderer()
Creates a default table cell renderer.

 

               
      
	super();
	setOpaque(true);
        setBorder(noFocusBorder);
Methods Summary
protected voidfirePropertyChange(java.lang.String propertyName, java.lang.Object oldValue, java.lang.Object newValue)
Overridden for performance reasons. See the Implementation Note for more information.

	
	// Strings get interned...
	if (propertyName=="text") {
	    super.firePropertyChange(propertyName, oldValue, newValue);
	}
public voidfirePropertyChange(java.lang.String propertyName, boolean oldValue, boolean newValue)
Overridden for performance reasons. See the Implementation Note for more information.
public java.awt.ComponentgetTableCellRendererComponent(javax.swing.JTable table, java.lang.Object value, boolean isSelected, boolean hasFocus, int row, int column)
Returns the default table cell renderer.

param
table the JTable
param
value the value to assign to the cell at [row, column]
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


	if (isSelected) {
	   super.setForeground(table.getSelectionForeground());
	   super.setBackground(table.getSelectionBackground());
	}
	else {
	    super.setForeground((unselectedForeground != null) ? unselectedForeground 
	                                                       : table.getForeground());
	    super.setBackground((unselectedBackground != null) ? unselectedBackground 
	                                                       : table.getBackground());
	}
	
	setFont(table.getFont());

	if (hasFocus) {
            Border border = null;
            if (isSelected) {
                border = UIManager.getBorder("Table.focusSelectedCellHighlightBorder");
            }
            if (border == null) {
                border = UIManager.getBorder("Table.focusCellHighlightBorder");
            }
            setBorder(border);

	    if (!isSelected && table.isCellEditable(row, column)) {
                Color col;
                col = UIManager.getColor("Table.focusCellForeground");
                if (col != null) {
                    super.setForeground(col);
                }
                col = UIManager.getColor("Table.focusCellBackground");
                if (col != null) {
                    super.setBackground(col);
                }
	    }
	} else {
	    setBorder(noFocusBorder);
	}

        setValue(value); 

	return this;
public voidinvalidate()
Overridden for performance reasons. See the Implementation Note for more information.

since
1.5

public booleanisOpaque()
Overridden for performance reasons.
See the Implementation Note
for more information.
 
	Color back = getBackground();
	Component p = getParent(); 
	if (p != null) { 
	    p = p.getParent(); 
	}
	// p should now be the JTable. 
	boolean colorMatch = (back != null) && (p != null) && 
	    back.equals(p.getBackground()) && 
			p.isOpaque();
	return !colorMatch && super.isOpaque(); 
    
public voidrepaint(long tm, int x, int y, int width, int height)
Overridden for performance reasons.
See the Implementation Note
for more information.
public voidrepaint(java.awt.Rectangle r)
Overridden for performance reasons.
See the Implementation Note
for more information.
 
public voidrepaint()
Overridden for performance reasons.
See the Implementation Note
for more information.
since
1.5
    
public voidrevalidate()
Overridden for performance reasons.
See the Implementation Note
for more information.
public voidsetBackground(java.awt.Color c)
Overrides JComponent.setBackground to assign
the unselected-background color to the specified color.
param
c set the background color to this value
        super.setBackground(c); 
        unselectedBackground = c; 
    
public voidsetForeground(java.awt.Color c)
Overrides JComponent.setForeground to assign
the unselected-foreground color to the specified color.
param
c set the foreground color to this value
        super.setForeground(c); 
        unselectedForeground = c; 
    
protected voidsetValue(java.lang.Object value)
Sets the String object for the cell being rendered to
value.
param
value the string value for this cell; if value is
null it sets the text value to an empty string
see
JLabel#setText
	setText((value == null) ? "" : value.toString());
    
public voidupdateUI()
Notification from the UIManager that the look and feel
[L&F] has changed.
Replaces the current UI object with the latest version from the
UIManager.
see
JComponent#updateUI
        super.updateUI(); 
	setForeground(null);
	setBackground(null);
    
public voidvalidate()
Overridden for performance reasons.
See the Implementation Note
for more information.