org.snmp4j

Interface MessageDispatcher

All Superinterfaces:

TransportListener

All Known Implementing Classes:

MessageDispatcherImpl, MultiThreadedMessageDispatcher

public interface MessageDispatcher
extends TransportListener

The MessageDispatcher interface defines common services of instances that process incoming SNMP messages and dispatch them to interested CommandResponder instances. It also provides a service to send out outgoing SNMP messages.

A MessageDispatcher needs at least one TransportMapping and at least one MessageProcessingModel in order to be able to process any messages.

Version:

2.0

Author:

Frank Fock

Method Summary

Methods

Modifier and Type	Method and Description
void	addCommandResponder(CommandResponder listener) Adds a CommandResponder instance to the message dispatcher.
void	addMessageProcessingModel(MessageProcessingModel model) Adds a MessageProcessingModel to the dispatcher.
void	addTransportMapping(TransportMapping<? extends Address> transport) Adds a TransportMapping to the dispatcher.
MessageProcessingModel	getMessageProcessingModel(int messageProcessingModel) Gets the MessageProcessingModel for the supplied message processing model ID.
int	getNextRequestID() Gets the next unique request ID.
TransportMapping	getTransport(Address destAddress) Returns a transport mapping that can handle the supplied address.
Collection<TransportMapping>	getTransportMappings() Gets the Collection of transport mappings in this message dispatcher.
void	processMessage(TransportMapping sourceTransport, Address incomingAddress, ByteBuffer wholeMessage, TransportStateReference tmStateReference) Process an incoming SNMP message.
void	releaseStateReference(int messageProcessingModel, PduHandle pduHandle) Release any state references associated with the supplied PduHandle in the specified message processing model.
void	removeCommandResponder(CommandResponder listener) Removes a previously added CommandResponder instance from the message dispatcher.
void	removeMessageProcessingModel(MessageProcessingModel model) Removes a previously added MessageProcessingModel from the dispatcher.
TransportMapping	removeTransportMapping(TransportMapping<? extends Address> transport) Removes a previously added TransportMapping from the dispatcher.
int	returnResponsePdu(int messageProcessingModel, int securityModel, byte[] securityName, int securityLevel, PDU pdu, int maxSizeResponseScopedPDU, StateReference stateReference, StatusInformation statusInformation) Returns a response PDU to the sender of the corresponding request PDU.
PduHandle	sendPdu(Target target, PDU pdu, boolean expectResponse) Sends a PDU to the supplied transport address.
PduHandle	sendPdu(TransportMapping transportMapping, Target target, PDU pdu, boolean expectResponse) Sends a PDU to the supplied transport address.
PduHandle	sendPdu(TransportMapping transportMapping, Target target, PDU pdu, boolean expectResponse, PduHandleCallback<PDU> callback) Sends a PDU to the supplied transport address and returns the PduHandle that uniquely identifies the request as response after the request has been sent and optional, if a PduHandleCallback is given, it returns also the PduHandle just before the request is sent through the the callback interface.

Method Detail

getNextRequestID

int getNextRequestID()

Gets the next unique request ID. The returned ID is unique across the last 2^31-1 IDs generated by this message dispatcher.

Returns:

an integer value in the range 1..2^31-1. The returned ID can be used to map responses to requests send through this message dispatcher.

Since:

1.1

addMessageProcessingModel

void addMessageProcessingModel(MessageProcessingModel model)

Adds a MessageProcessingModel to the dispatcher. In order to support a specific SNMP protocol version, the message dispatcher needs a message processing model to process messages before they can be dispatched.

Parameters:

model - a MessageProcessingModel instance.

removeMessageProcessingModel

void removeMessageProcessingModel(MessageProcessingModel model)

Removes a previously added MessageProcessingModel from the dispatcher.

Parameters:

model - a MessageProcessingModel instance.

getMessageProcessingModel

MessageProcessingModel getMessageProcessingModel(int messageProcessingModel)

Gets the MessageProcessingModel for the supplied message processing model ID.

Parameters:

messageProcessingModel - a message processing model ID (see MessageProcessingModel.getID()).

Returns:

a MessageProcessingModel instance if the ID is known, otherwise null

addTransportMapping

void addTransportMapping(TransportMapping<? extends Address> transport)

Adds a TransportMapping to the dispatcher. The transport mapping is used to send and receive messages to/from the network.

Parameters:

transport - a TransportMapping instance.

removeTransportMapping

TransportMapping removeTransportMapping(TransportMapping<? extends Address> transport)

Removes a previously added TransportMapping from the dispatcher.

Parameters:

transport - a TransportMapping instance.

Returns:

the TransportMapping instance supplied if it could be successfully removed, null otherwise.

getTransportMappings

Collection<TransportMapping> getTransportMappings()

Gets the Collection of transport mappings in this message dispatcher.

Returns:

a Collection with the registered transport mappings.

getTransport

TransportMapping getTransport(Address destAddress)

Returns a transport mapping that can handle the supplied address.

Parameters:

destAddress - an Address instance.

Returns:

a TransportMapping instance that can be used to sent a SNMP message to destAddress or null if such a transport mapping does not exists.

Since:

1.6

addCommandResponder

void addCommandResponder(CommandResponder listener)

Adds a CommandResponder instance to the message dispatcher. Successfully processed SNMP messages will be presented to all command responder (in the order in which they have been added) until a responder uses the CommandResponderEvent.setProcessed(boolean processed) to set the processed status of the event to true.

Parameters:

listener - a CommandResponder instance.

removeCommandResponder

void removeCommandResponder(CommandResponder listener)

Removes a previously added CommandResponder instance from the message dispatcher.

Parameters:

listener - a CommandResponder instance.

sendPdu

PduHandle sendPdu(TransportMapping transportMapping,
                Target target,
                PDU pdu,
                boolean expectResponse)
                  throws MessageException

Sends a PDU to the supplied transport address.

Parameters:

transportMapping - the TransportMapping to be used to send the PDU. If transportMapping is null the message dispatcher will determine the appropriate transport mapping for the given transport address.

target - the target which identifies, transport address, message processing model, security model, security name and level.

pdu - the SNMP Protocol Data Unit

expectResponse - true if a response is expected and a state reference should be saved (if needed for the supplied message processing model).

Returns:

an PduHandle that uniquely identifies this request.

Throws:

MessageException

sendPdu

PduHandle sendPdu(TransportMapping transportMapping,
                Target target,
                PDU pdu,
                boolean expectResponse,
                PduHandleCallback<PDU> callback)
                  throws MessageException

Sends a PDU to the supplied transport address and returns the PduHandle that uniquely identifies the request as response after the request has been sent and optional, if a PduHandleCallback is given, it returns also the PduHandle just before the request is sent through the the callback interface.

Parameters:

transportMapping - the TransportMapping to be used to send the PDU. If transportMapping is null the message dispatcher will determine the appropriate transport mapping for the given transport address.

target - the target which identifies, transport address, message processing model, security model, security name and level.

pdu - the SNMP Protocol Data Unit

expectResponse - true if a response is expected and a state reference should be saved (if needed for the supplied message processing model).

callback - an optional callback instance that is informed (if not null) about the newly assigned PduHandle just before the message is sent out.

Returns:

an PduHandle that uniquely identifies this request.

Throws:

MessageException

sendPdu

PduHandle sendPdu(Target target,
                PDU pdu,
                boolean expectResponse)
                  throws MessageException

Sends a PDU to the supplied transport address. This method behaves like a call to sendPdu(TransportMapping transportMapping, Target target, PDU pdu, boolean expectResponse) with transportMapping set to null.

Parameters:

target - the target which identifies, transport address, message processing model, security model, security name and level.

pdu - the SNMP Protocol Data Unit

expectResponse - true if a response is expected and a state reference should be saved (if needed for the supplied message processing model).

Returns:

an PduHandle that uniquely identifies this request.

Throws:

MessageException

returnResponsePdu

int returnResponsePdu(int messageProcessingModel,
                    int securityModel,
                    byte[] securityName,
                    int securityLevel,
                    PDU pdu,
                    int maxSizeResponseScopedPDU,
                    StateReference stateReference,
                    StatusInformation statusInformation)
                      throws MessageException

Returns a response PDU to the sender of the corresponding request PDU.

Parameters:

messageProcessingModel - int

securityModel - int

securityName - byte[]

securityLevel - int

pdu - PDU

maxSizeResponseScopedPDU - int

stateReference - StateReference

statusInformation - StatusInformation

Returns:

an MP error status or SnmpConstants.SNMP_MP_OK if the operation was successful.

Throws:

MessageException - if message processing fails with a fatal error.

processMessage

void processMessage(TransportMapping sourceTransport,
                  Address incomingAddress,
                  ByteBuffer wholeMessage,
                  TransportStateReference tmStateReference)

Process an incoming SNMP message. The message is processed and dispatched according to the message's content, the message processing models, and the command responder available to the dispatcher.

Specified by:

processMessage in interface TransportListener

Parameters:

sourceTransport - a TransportMapping instance denoting the transport that received the message and that will be used to send any responses to this message. The sourceTransport has to support the incomingAddress's implementation class.

incomingAddress - the Address from which the message has been received.

wholeMessage - an ByteBuffer containing the received SNMP message.

tmStateReference - the transport model state reference as defined by RFC 5590.

releaseStateReference

void releaseStateReference(int messageProcessingModel,
                         PduHandle pduHandle)

Release any state references associated with the supplied PduHandle in the specified message processing model.

Parameters:

messageProcessingModel - a message processing model ID.

pduHandle - the PduHandle that identifies a confirmed class message.

See Also:

MessageProcessingModel