.. php:namespace:: DreamCommerce\Exception
.. php:class:: HandlerException
An exception raised upon billing system responder error.
ACTION_HANDLER_NOT_EXISTS- action handler doesn't exist
ACTION_NOT_EXISTS- tried to handle non-existing action
ACTION_NOT_SPECIFIED- an action to handle has not been specified
CLIENT_INITIALIZATION_FAILED- an error occurred upon client class initialization - probably invalid data/tokens provided
HASH_FAILED- packet checksum is invalid
INCORRECT_HANDLER_SPECIFIED- handler for action is invalid
PAYLOAD_EMPTY- server returned a response with no data