/*
 * @(#)CellRendererPane.java	1.40 05/11/17
 *
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
package javax.swing;

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.beans.PropertyChangeListener;
import java.util.Locale;
import java.util.Vector;

import javax.accessibility.*;

/** 
 * This class is inserted in between cell renderers and the components that 
 * use them.  It just exists to thwart the repaint() and invalidate() methods 
 * which would otherwise propagate up the tree when the renderer was configured.
 * It's used by the implementations of JTable, JTree, and JList.  For example,
 * here's how CellRendererPane is used in the code the paints each row
 * in a JList:
 * <pre>
 *   cellRendererPane = new CellRendererPane();
 *   ...
 *   Component rendererComponent = renderer.getListCellRendererComponent();
 *   renderer.configureListCellRenderer(dataModel.getElementAt(row), row);
 *   cellRendererPane.paintComponent(g, rendererComponent, this, x, y, w, h);
 * </pre>
 * <p>
 * A renderer component must override isShowing() and unconditionally return
 * true to work correctly because the Swing paint does nothing for components
 * with isShowing false.  
 * <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<sup><font size="-2">TM</font></sup>
 * has been added to the <code>java.beans</code> package.
 * Please see {@link java.beans.XMLEncoder}.
 *
 * @version 1.40 11/17/05
 * @author Hans Muller
 */
public class CellRendererPane extends Container implements Accessible
{
    /**
     * Construct a CellRendererPane object.
     */
    public CellRendererPane() {
	super();
	setLayout(null);
	setVisible(false);
    }

    /** 
     * Overridden to avoid propagating a invalidate up the tree when the
     * cell renderer child is configured.
     */
    public void invalidate() { }


    /** 
     * Shouldn't be called.
     */
    public void paint(Graphics g) { }

  
    /**
     * Shouldn't be called.
     */
    public void update(Graphics g) { }


    /** 
     * If the specified component is already a child of this then we don't
     * bother doing anything - stacking order doesn't matter for cell
     * renderer components (CellRendererPane doesn't paint anyway).<
     */
    protected void addImpl(Component x, Object constraints, int index) {
	if (x.getParent() == this) {
	    return;
	}
	else {
	    super.addImpl(x, constraints, index);
	}
    }


    /** 
     * Paint a cell renderer component c on graphics object g.  Before the component
     * is drawn it's reparented to this (if that's necessary), it's bounds 
     * are set to w,h and the graphics object is (effectively) translated to x,y.  
     * If it's a JComponent, double buffering is temporarily turned off. After 
     * the component is painted it's bounds are reset to -w, -h, 0, 0 so that, if 
     * it's the last renderer component painted, it will not start consuming input.