abstract public Class<?> getCommonPropertyType(ELContext context,
    Object base)

 abstract public Iterator<FeatureDescriptor> getFeatureDescriptors(ELContext context,
    Object base)

 abstract public Class<?> getType(ELContext context,
    Object base,
    Object property) throws NullPointerException, PropertyNotFoundException, ELException

 abstract public Object getValue(ELContext context,
    Object base,
    Object property) throws NullPointerException, PropertyNotFoundException, ELException

 abstract public boolean isReadOnly(ELContext context,
    Object base,
    Object property) throws NullPointerException, PropertyNotFoundException, ELException

 static String message(ELContext context,
    String name,
    Object[] props) 
{
		Locale locale = context.getLocale();
		if (locale == null) {
			locale = Locale.getDefault();
			if (locale == null) {
				return "";
			}
		}
		ResourceBundle bundle = ResourceBundle.getBundle(
				"javax.el.LocalStrings", locale);
		try {
			String template = bundle.getString(name);
			if (props != null) {
				template = MessageFormat.format(template, props);
			}
			return template;
		} catch (MissingResourceException e) {
			return "Missing Resource: '" + name + "' for Locale "
					+ locale.getDisplayName();
		}
}

 abstract public  void setValue(ELContext context,
    Object base,
    Object property,
    Object value) throws NullPointerException, PropertyNotFoundException, PropertyNotWritableException, ELException