class OWSException(Exception):
    pass

class WMSException(OWSException):
    def toXml(self):
        print  """Content-type: text/xml\n"""

        print """<?xml version="1.0" ?>
        <ServiceExceptionReport version="1.3.0" xmlns="http://www.opengis.net/ogc"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://www.opengis.net/ogc http://schemas.opengis.net/wms/1.3.0/exceptions_1_3_0.xsd">
        <ServiceException code="%s" locator="%s"><![CDATA[
        %s
        ]]></ServiceException>
        </ServiceExceptionReport>""" % \
                (self.__class__.__name__,self.message,self.args)

class MissingParameterValue(WMSException):
    pass

class RequestFailed(WMSException):
    pass
class NoValidRequest(WMSException):
    pass