Bug 149922 Image builder - URI and file source type are treated as same
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/util/StringUtil.java
* @param rgb
	 *            the integer RGB value
	 * @return the value as an HTML RGB string
	 */
	public static String toRgbText( int rgb )
	{
		
		if ( rgb > 0xFFFFFF )
			rgb = 0xFFFFFF;
		if ( rgb < 0 )
			rgb = 0;
		String str = "000000" + Integer.toHexString( rgb );  
		return "#" + str.substring( str.length( ) - 6 );  
	}
	/**
	 * Check if the locale string is a valid locale format, with the language,
	 * country and variant separated by underbars.
	 * <p>
	 * The language argument is a valid <STRONG>ISO Language Code. </STRONG>.
	 * These codes are the lower-case, two-letter codes.
	 * <p>
	 * The country argument is a valid <STRONG>ISO Country Code. </STRONG> These
	 * codes are the upper-case, two-letter codes.
	 * <p>
	 * If the language is missing, the string should begin with an underbar.
	 * (Can't have a locale with just a variant -- the variant must accompany a
	 * valid language or country code). Examples: "en", "de_DE", "_GB",
	 * "en_US_WIN", "de__POSIX", "fr__MAC"
	 * 
	 * @param locale