Table 1A: Exceptions

The following table details each of the exception types thrown by AMPS.

Exception	When	Notes
AlreadyConnectedError	Connecting	Thrown when connect() is called on a Client that is already connected.
AMPSError	Anytime	Base class for all AMPS exceptions.
AuthenticationError	Anytime	Indicates an authentication failure occurred on the server.
BadFilterError	Subscribing	This typically indicates a syntax error in a filter expression.
BadRegexTopicError	Subscribing	Indicates a malformed regular expression was found in the topic name.
CommandError	Anytime	Base class for all exceptions relating to commands sent to AMPS.
ConnectionError	Anytime	Base class for all exceptions relating to the state of the AMPS connection.
ConnectionRefusedError	Connecting	The connection was actively refused by the server. Validate that the server is running, that network connectivity is available, and the settings on the client match those on the server.
DisconnectedError	Anytime	No connection is available when AMPS needed to send data to the server or the user’s disconnect handler threw an exception.
InvalidTopicError	SOW query	The topic is not configured for the requested operation. For example, a sow command was issued for a topic that is not in the SOW or a bookmark subscribe was issued for a topic that is not recorded in the transaction log.
InvalidTransportOptionsError	Connecting	An invalid option or option value was specified in the URI.
InvalidURIError	Connecting	The URI string provided to connect() was formatted improperly.
MessageTypeError	Connecting	The class for a given transport’s message type was not found in AMPS.
MessageTypeNotFoundError	Connecting	The message type specified in the URI was not found in AMPS.
NameInUseError	Connecting	The client name (specified when instantiating Client) is already in use on the server.
RetryOperationError	Anytime	An error occurred that caused processing of the last command to be aborted. Try issuing the command again.
StreamError	Anytime	Indicates that data corruption has occurred on the connection between the client and server. This usually indicates an internal error inside of AMPS – contact AMPS support.
SubscriptionAlreadyExistsExc eption	Subscribing	A subscription has been requested using the same command ID string as another subscription. Create a unique command ID string for every subscription.
TimedOutError	Anytime	A timeout occurred waiting for a response to a command.
TransportTypeError	Connecting	Thrown when a transport type is selected in the URI that is unknown to AMPS.
UnknownError	Anytime	Thrown when an internal error occurs. Contact AMPS support immediately.
UsageException	Changing the properties of an object	Thrown when the object is not in a valid state for setting the properties. For example, some properties of a Client (such as the BookmarkStore used) cannot be changed while that client is connected to AMPS.

Table 1A: Exceptions supported in Client and HAClient