PropertyType.ELEMENT_REF_TYPE );
PropertyType.EXTENDS_TYPE );
	public Object validateValue( Module module, PropertyDefn defn, Object value )			throws PropertyValueException	{		if ( value == null )			return null;		// This implementation assumes that the class-specific validation		// was already done.		if ( value instanceof String )		{			String name = StringUtil.trimString( (String) value );			if ( name == null )			{				logger.log( Level.SEVERE,						"The value of the extends property is an empty string" ); //$NON-NLS-1$				return null;			}			// Element is unresolved.			return validateStringValue( module, defn, (String) value );		}		if ( value instanceof DesignElement )		{			// Resolved reference.			return validateElementValue( module, defn, (DesignElement) value );		}		// Invalid property value.		logger.log( Level.SEVERE,				"The value of the extends property is not a valid type " ); //$NON-NLS-1$		throw new PropertyValueException( value,				PropertyValueException.DESIGN_EXCEPTION_INVALID_VALUE,				PropertyType.ELEMENT_REF_TYPE );	}