/**
 * Parses a CSS resource and get the CSSStyleSheet as the output.
 * 
 * @param source
 *            the source of the CSS resource
 * @return the CSSStyleSheet if succeed
 * @throws IOException
 *             if the resource is not well-located
 */

public CSSStyleSheet parseStyleSheet( InputSource source )
		throws IOException
{
	CssHandler handler = new CssHandler( );
	parser.setDocumentHandler( handler );
	parser.setErrorHandler( errorHandler );
	try 
	{
		parser.parseStyleSheet( source );
	}
	catch ( StringIndexOutOfBoundsException e ) 
	{
		throw new CSSException( CSSException.SAC_SYNTAX_ERR );
	}
	return (StyleSheet) handler.getRoot( );
}
 

private static String processStyles(String tag, String clazz, String style, List<CSSStyleSheet> sheets) {
    for (CSSStyleSheet sheet : sheets)
        if (isScreenMedia(sheet.getMedia())) {
            style = processStyles(null, clazz, style, sheet.getCssRules(), Selector.SAC_ELEMENT_NODE_SELECTOR);
            style = processStyles(tag, clazz, style, sheet.getCssRules(), Selector.SAC_ELEMENT_NODE_SELECTOR);
            style = processStyles(tag, clazz, style, sheet.getCssRules(), Selector.SAC_CONDITIONAL_SELECTOR);
        }
    return style;
}
 

/**
 * Returns the cached parsed version of the specified CSS snippet. If there is no
 * corresponding cached stylesheet, this method returns {@code null}.
 *
 * @param css the CSS snippet whose cached stylesheet is sought
 * @return the cached stylesheet corresponding to the specified CSS snippet
 */
public CSSStyleSheet getCachedStyleSheet(final String css) {
    final Entry cachedEntry = entries_.get(css);
    if (cachedEntry == null) {
        return null;
    }
    synchronized (entries_) {
        cachedEntry.touch();
    }
    return (CSSStyleSheet) cachedEntry.value_;
}
 

public CSSStyleSheet getParentStyleSheet( )
{
	return null;
}
 

public CSSStyleSheet getParentStyleSheet( )
{
	return null;
}
 

/**
 * Caches the parsed version of the specified CSS snippet. We key the cache based on CSS snippets (rather
 * than requests and responses as is done above) because a) this allows us to cache inline CSS, b) CSS is
 * extremely expensive to parse, so we want to avoid it as much as possible, c) CSS files aren't usually
 * nearly as large as JavaScript files, so memory bloat won't be too bad, and d) caching on requests and
 * responses requires checking dynamicity (see {@link #isCacheableContent(WebResponse)}), and headers often
 * aren't set up correctly, disallowing caching when in fact it should be allowed.
 *
 * @param css the CSS snippet from which <tt>styleSheet</tt> is derived
 * @param styleSheet the parsed version of <tt>css</tt>
 */
public void cache(final String css, final CSSStyleSheet styleSheet) {
    final Entry entry = new Entry(css, null, styleSheet);
    entries_.put(entry.key_, entry);
    deleteOverflow();
}