org.snmp4j

Class Snmp

java.lang.Object

org.snmp4j.Snmp

All Implemented Interfaces:

EventListener, CommandResponder, Session

public class Snmp
extends Object
implements Session, CommandResponder

The Snmp class is the core of SNMP4J. It provides functions to send and receive SNMP PDUs. All SNMP PDU types can be send. Confirmed PDUs can be sent synchronously and asynchronously.

The Snmp class is transport protocol independent. Support for a specific TransportMapping instance is added by calling the addTransportMapping(TransportMapping transportMapping) method or creating a Snmp instance by using the non-default constructor with the corresponding transport mapping. Transport mappings are used for incoming and outgoing messages.

To setup a default SNMP session for UDP transport and with SNMPv3 support the following code snippet can be used:

   Address targetAddress = GenericAddress.parse("udp:127.0.0.1/161");
   TransportMapping transport = new DefaultUdpTransportMapping();
   snmp = new Snmp(transport);
   USM usm = new USM(SecurityProtocols.getInstance(),
                     new OctetString(MPv3.createLocalEngineID()), 0);
   SecurityModels.getInstance().addSecurityModel(usm);
   transport.listen();
 

How a synchronous SNMPv3 message with authentication and privacy is then sent illustrates the following code snippet:

   // add user to the USM
   snmp.getUSM().addUser(new OctetString("MD5DES"),
                         new UsmUser(new OctetString("MD5DES"),
                                     AuthMD5.ID,
                                     new OctetString("MD5DESUserAuthPassword"),
                                     PrivDES.ID,
                                     new OctetString("MD5DESUserPrivPassword")));
   // create the target
   UserTarget target = new UserTarget();
   target.setAddress(targetAddress);
   target.setRetries(1);
   target.setTimeout(5000);
   target.setVersion(SnmpConstants.version3);
   target.setSecurityLevel(SecurityLevel.AUTH_PRIV);
   target.setSecurityName(new OctetString("MD5DES"));

   // create the PDU
   PDU pdu = new ScopedPDU();
   pdu.add(new VariableBinding(new OID("1.3.6")));
   pdu.setType(PDU.GETNEXT);

   // send the PDU
   ResponseEvent response = snmp.send(pdu, target);
   // extract the response PDU (could be null if timed out)
   PDU responsePDU = response.getResponse();
   // extract the address used by the agent to send the response:
   Address peerAddress = response.getPeerAddress();
 

An asynchronous SNMPv1 request is sent by the following code:

   // setting up target
   CommunityTarget target = new CommunityTarget();
   target.setCommunity(new OctetString("public"));
   target.setAddress(targetAddress);
   target.setRetries(2);
   target.setTimeout(1500);
   target.setVersion(SnmpConstants.version1);
   // creating PDU
   PDU pdu = new PDU();
   pdu.add(new VariableBinding(new OID(new int[] {1,3,6,1,2,1,1,1})));
   pdu.add(new VariableBinding(new OID(new int[] {1,3,6,1,2,1,1,2})));
   pdu.setType(PDU.GETNEXT);
   // sending request
   ResponseListener listener = new ResponseListener() {
     public void onResponse(ResponseEvent event) {
       // Always cancel async request when response has been received
       // otherwise a memory leak is created! Not canceling a request
       // immediately can be useful when sending a request to a broadcast
       // address.
       ((Snmp)event.getSource()).cancel(event.getRequest(), this);
       System.out.println("Received response PDU is: "+event.getResponse());
     }
   };
   snmp.sendPDU(pdu, target, null, listener);
 

Traps (notifications) and other SNMP PDUs can be received by adding the following code to the first code snippet above:

   CommandResponder trapPrinter = new CommandResponder() {
     public synchronized void processPdu(CommandResponderEvent e) {
       PDU command = e.getPDU();
       if (command != null) {
         System.out.println(command.toString());
       }
     }
   };
   snmp.addCommandResponder(trapPrinter);
 

Version:

1.10

Author:

Frank Fock

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	Snmp.ReportHandler Interface for handling reports.

Constructor Summary

Constructors

Constructor and Description
Snmp() Creates a Snmp instance that uses a MessageDispatcherImpl with no message processing models and no security protols (by default).
Snmp(MessageDispatcher messageDispatcher) Creates a Snmp instance by supplying a MessageDispatcher.
Snmp(MessageDispatcher messageDispatcher, TransportMapping<? extends Address> transportMapping) Creates a Snmp instance by supplying a MessageDispatcher and a TransportMapping.
Snmp(TransportMapping<? extends Address> transportMapping) Creates a Snmp instance that uses a MessageDispatcherImpl with all supported message processing models and the default security protols for dispatching.

Method Summary

Modifier and Type	Method and Description
void	addCommandResponder(CommandResponder listener) Adds a CommandResponder to this SNMP session.
boolean	addNotificationListener(Address listenAddress, CommandResponder listener) Adds a notification listener to this Snmp instance.
boolean	addNotificationListener(TransportMapping transportMapping, Address listenAddress, CommandResponder listener) Adds a notification listener to this Snmp instance.
void	addTransportMapping(TransportMapping<? extends Address> transportMapping) Adds a TransportMapping to this SNMP session.
void	cancel(PDU request, ResponseListener listener) Cancels an asynchronous request.
void	close() Closes the session and frees any allocated resources, i.e.
protected void	closeTransportMapping(TransportMapping tm)
byte[]	discoverAuthoritativeEngineID(Address address, long timeout) Discovers the engine ID of the SNMPv3 entity denoted by the supplied address.
protected void	fireProcessPdu(CommandResponderEvent event) Fires a CommandResponderEvent event to inform listeners about a received PDU.
ResponseEvent	get(PDU pdu, Target target) Sends a GET request to a target.
void	get(PDU pdu, Target target, Object userHandle, ResponseListener listener) Asynchronously sends a GET request PDU to the given target.
ResponseEvent	getBulk(PDU pdu, Target target) Sends a GETBULK request to a target.
void	getBulk(PDU pdu, Target target, Object userHandle, ResponseListener listener) Asynchronously sends a GETBULK request PDU to the given target.
CounterSupport	getCounterSupport() Gets the counter support for Snmp related counters.
byte[]	getLocalEngineID() Gets the local engine ID if the MPv3 is available, otherwise a runtime exception is thrown.
MessageDispatcher	getMessageDispatcher() Returns the message dispatcher associated with this SNMP session.
MessageProcessingModel	getMessageProcessingModel(int messageProcessingModel) Gets the message processing model for the supplied ID.
ResponseEvent	getNext(PDU pdu, Target target) Sends a GETNEXT request to a target.
void	getNext(PDU pdu, Target target, Object userHandle, ResponseListener listener) Asynchronously sends a GETNEXT request PDU to the given target.
int	getNextRequestID() Gets the next unique request ID.
TransportMapping	getNotificationListenerTM(Address listenAddress) Gets the transport mapping registered for the specified listen address.
int	getPendingAsyncRequestCount() Gets the number of currently pending asynchronous requests.
int	getPendingSyncRequestCount() Gets the number of currently pending synchronous requests.
Snmp.ReportHandler	getReportHandler() Returns the report handler which is used internally to process reports received from command responders.
TimeoutModel	getTimeoutModel() Gets the timeout model associated with this SNMP session.
USM	getUSM() Gets the User Based Security Model (USM).
protected void	handleInternalResponse(PDU response, PDU pdu, Address target)
ResponseEvent	inform(PDU pdu, Target target) Sends an INFORM request to a target.
void	inform(PDU pdu, Target target, Object userHandle, ResponseListener listener) Asynchronously sends an INFORM request PDU to the given target.
protected void	initMessageDispatcher()
boolean	isContextEngineIdDiscoveryDisabled() Checks whether RFC5343 based context engine ID discovery is disabled or not.
void	listen() Puts all associated transport mappings into listen mode.
protected TransportMapping	lookupTransportMapping(Target target)
void	notify(PDU pdu, Target target) Sends a SNMPv2c or SNMPv3 notification to a target.
void	processPdu(CommandResponderEvent event) Process an incoming request or notification PDU.
void	removeCommandResponder(CommandResponder listener) Removes a CommandResponder from this SNMP session.
boolean	removeNotificationListener(Address listenAddress) Removes (deletes) the notification listener for the specified transport endpoint.
void	removeTransportMapping(TransportMapping<? extends Address> transportMapping) Removes the specified transport mapping from this SNMP session.
protected boolean	resendRequest(org.snmp4j.Snmp.PendingRequest request, PDU response)
ResponseEvent	send(PDU pdu, Target target) Sends a PDU to the given target and returns the received response PDU.
void	send(PDU pdu, Target target, Object userHandle, ResponseListener listener) Asynchronously sends a PDU to the given target.
ResponseEvent	send(PDU pdu, Target target, TransportMapping transport) Sends a PDU to the given target and if the PDU is a confirmed request, then the received response is returned synchronously.
void	send(PDU pdu, Target target, TransportMapping transport, Object userHandle, ResponseListener listener) Asynchronously sends a PDU to the given target.
protected PduHandle	sendMessage(PDU pdu, Target target, TransportMapping transport, PduHandleCallback<PDU> pduHandleCallback) Actually sends a PDU to a target and returns a handle for the sent PDU.
ResponseEvent	set(PDU pdu, Target target) Sends a SET request to a target.
void	set(PDU pdu, Target target, Object userHandle, ResponseListener listener) Asynchronously sends a SET request PDU to the given target.
void	setContextEngineIdDiscoveryDisabled(boolean contextEngineIdDiscoveryDisabled) Sets the RFC5343 based context engine ID discovery.
void	setCounterSupport(CounterSupport counterSupport) Sets the counter support instance to handle counter events on behalf of this Snmp instance.
void	setLocalEngine(byte[] engineID, int engineBoots, int engineTime) Sets the local engine ID for the SNMP entity represented by this Snmp instance.
void	setMessageDispatcher(MessageDispatcher messageDispatcher) Sets the message dispatcher associated with this SNMP session.
void	setReportHandler(Snmp.ReportHandler reportHandler) Sets the report handler and overrides the default report handler.
void	setTimeoutModel(TimeoutModel timeoutModel) Sets the timeout model for this SNMP session.
void	trap(PDUv1 pdu, Target target) Sends a SNMPv1 trap to a target.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Snmp

public Snmp()

Creates a Snmp instance that uses a MessageDispatcherImpl with no message processing models and no security protols (by default). You will have to add those by calling the appropriate methods on getMessageDispatcher().

At least one transport mapping has to be added before listen() is called in order to be able to send and receive SNMP messages.

To initialize a Snmp instance created with this constructor follow this sample code:

 Transport transport = ...;
 Snmp snmp = new Snmp();
 SecurityProtocols.getInstance().addDefaultProtocols();
 MessageDispatcher disp = snmp.getMessageDispatcher();
 disp.addMessageProcessingModel(new MPv1());
 disp.addMessageProcessingModel(new MPv2c());
 snmp.addTransportMapping(transport);
 OctetString localEngineID = new OctetString(
    MPv3.createLocalEngineID());
    // For command generators, you may use the following code to avoid
    // engine ID clashes:
    // MPv3.createLocalEngineID(
    //   new OctetString("MyUniqueID"+System.currentTimeMillis())));
 USM usm = new USM(SecurityProtocols.getInstance(), localEngineID, 0);
 disp.addMessageProcessingModel(new MPv3(usm));
 snmp.listen();
 

Snmp

public Snmp(TransportMapping<? extends Address> transportMapping)

Creates a Snmp instance that uses a MessageDispatcherImpl with all supported message processing models and the default security protols for dispatching.

To initialize a Snmp instance created with this constructor follow this sample code:

 Transport transport = ...;
 Snmp snmp = new Snmp(transport);
 OctetString localEngineID =
   new OctetString(snmp.getMPv3().getLocalEngineID());
 USM usm = new USM(SecurityProtocols.getInstance(), localEngineID, 0);
 SecurityModels.getInstance().addSecurityModel(usm);
 snmp.listen();
 

Parameters:

transportMapping - TransportMapping the initial TransportMapping. You can add more or remove the same later.

Snmp

public Snmp(MessageDispatcher messageDispatcher,
            TransportMapping<? extends Address> transportMapping)

Creates a Snmp instance by supplying a MessageDispatcher and a TransportMapping.

As of version 1.1, the supplied message dispatcher is not altered in terms of adding any message processing models to it. This has to be done now outside the Snmp class.

To initialize a Snmp instance created with this constructor follow this sample code:

 Transport transport = ...;
 SecurityProtocols.getInstance().addDefaultProtocols();
 MessageDispatcher disp = new MessageDispatcherImpl();
 disp.addMessageProcessingModel(new MPv1());
 disp.addMessageProcessingModel(new MPv2c());
 Snmp snmp = new Snmp(disp, transport);
 OctetString localEngineID = new OctetString(
    MPv3.createLocalEngineID());
    // For command generators, you may use the following code to avoid
    // engine ID clashes:
    // MPv3.createLocalEngineID(
    //   new OctetString("MyUniqueID"+System.currentTimeMillis())));
 USM usm = new USM(SecurityProtocols.getInstance(), localEngineID, 0);
 disp.addMessageProcessingModel(new MPv3(usm));
 snmp.listen();
 

Parameters:

messageDispatcher - a MessageDispatcher instance that will be used to dispatch incoming and outgoing messages.

transportMapping - the initial TransportMapping, which may be null. You can add or remove transport mappings later using addTransportMapping(org.snmp4j.TransportMapping<? extends org.snmp4j.smi.Address>) and removeTransportMapping(org.snmp4j.TransportMapping<? extends org.snmp4j.smi.Address>) respectively.

Snmp

public Snmp(MessageDispatcher messageDispatcher)

Creates a Snmp instance by supplying a MessageDispatcher.

The supplied message dispatcher is not altered in terms of adding any message processing models to it. This has to be done now outside the Snmp class.

Do not forget to add at least one transport mapping before calling the listen method!

To initialize a Snmp instance created with this constructor follow this sample code:

 Transport transport = ...;
 SecurityProtocols.getInstance().addDefaultProtocols();
 MessageDispatcher disp = new MessageDispatcherImpl();
 disp.addMessageProcessingModel(new MPv1());
 disp.addMessageProcessingModel(new MPv2c());
 Snmp snmp = new Snmp(disp);
 snmp.addTransportMapping(transport);
 OctetString localEngineID = new OctetString(
    MPv3.createLocalEngineID());
    // For command generators, you may use the following code to avoid
    // engine ID clashes:
    // MPv3.createLocalEngineID(
    //   new OctetString("MyUniqueID"+System.currentTimeMillis())));
 USM usm = new USM(SecurityProtocols.getInstance(), localEngineID, 0);
 disp.addMessageProcessingModel(new MPv3(usm));
 snmp.listen();
 

Parameters:

messageDispatcher - a MessageDispatcher instance that will be used to dispatch incoming and outgoing messages.

Since:

1.5

Method Detail

initMessageDispatcher

protected final void initMessageDispatcher()

getMessageDispatcher

public MessageDispatcher getMessageDispatcher()

Returns the message dispatcher associated with this SNMP session.

Returns:

a MessageDispatcher instance.

Since:

1.1

setMessageDispatcher

public void setMessageDispatcher(MessageDispatcher messageDispatcher)

Sets the message dispatcher associated with this SNMP session. The CommandResponder registration is removed from the existing message dispatcher (if not null).

Parameters:

messageDispatcher - a message dispatcher that processes incoming SNMP PDUs.

Since:

2.5.7

addTransportMapping

public void addTransportMapping(TransportMapping<? extends Address> transportMapping)

Adds a TransportMapping to this SNMP session.

Parameters:

transportMapping - a TransportMapping instance.

removeTransportMapping

public void removeTransportMapping(TransportMapping<? extends Address> transportMapping)

Removes the specified transport mapping from this SNMP session. If the transport mapping is not currently part of this SNMP session, this method will have no effect.

Parameters:

transportMapping - a previously added TransportMapping.

addNotificationListener

public boolean addNotificationListener(TransportMapping transportMapping,
                                       Address listenAddress,
                                       CommandResponder listener)

Adds a notification listener to this Snmp instance. Calling this method will create a transport mapping for the specified listening address and registers the provided CommandResponder with the internal NotificationDispatcher.

Parameters:

transportMapping - the TransportMapping that is listening on the provided listenAddress. Call TransportMappings.getInstance().createTransportMapping(listenAddress); to create such a transport mapping.

listenAddress - the Address denoting the transport end-point (interface and port) to listen for incoming notifications.

listener - the CommandResponder instance that should handle the received notifications.

Returns:

true if registration was successful and false if, for example, the transport mapping for the listen address could not be created.

Since:

2.5.0

addNotificationListener

public boolean addNotificationListener(Address listenAddress,
                                       CommandResponder listener)

Adds a notification listener to this Snmp instance. Calling this method will create a transport mapping for the specified listening address and registers the provided CommandResponder with the internal NotificationDispatcher.

Parameters:

listenAddress - the Address denoting the transport end-point (interface and port) to listen for incoming notifications.

listener - the CommandResponder instance that should handle the received notifications.

Returns:

true if registration was successful and false if, for example, the transport mapping for the listen address could not be created.

Since:

1.6

removeNotificationListener

public boolean removeNotificationListener(Address listenAddress)

Removes (deletes) the notification listener for the specified transport endpoint.

Parameters:

listenAddress - the listen Address to be removed.

Returns:

true if the notification listener has been removed successfully.

getNotificationListenerTM

public TransportMapping getNotificationListenerTM(Address listenAddress)

Gets the transport mapping registered for the specified listen address.

Parameters:

listenAddress - the listen address.

Returns:

the TransportMapping for the specified listen address or null if there is no notification listener for that address.

Since:

2.5.0

listen

public void listen()
            throws IOException

Puts all associated transport mappings into listen mode.

Throws:

IOException - if a transport mapping throws an IOException when its TransportMapping.listen() method has been called.

getNextRequestID

public 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

See Also:

MessageDispatcher.getNextRequestID()

close

public void close()
           throws IOException

Closes the session and frees any allocated resources, i.e. sockets and the internal thread for processing request timeouts.

If there are any pending requests, the ResponseListener associated with the pending requests, will be called with a null response and a InterruptedException in the error member of the ResponseEvent returned.

After a Session has been closed it must not be used anymore.

Specified by:

close in interface Session

Throws:

IOException - if a transport mapping cannot be closed successfully.

get

public ResponseEvent get(PDU pdu,
                         Target target)
                  throws IOException

Sends a GET request to a target. This method sets the PDU's type to PDU.GET and then sends a synchronous request to the supplied target.

Parameters:

pdu - a PDU instance. For SNMPv3 messages, the supplied PDU instance has to be a ScopedPDU instance.

target - the Target instance representing the target SNMP engine where to send the pdu.

Returns:

the received response encapsulated in a ResponseEvent instance. To obtain the received response PDU call ResponseEvent.getResponse(). If the request timed out, that method will return null.

Throws:

IOException - if the PDU cannot be sent to the target.

Since:

1.1

get

public void get(PDU pdu,
                Target target,
                Object userHandle,
                ResponseListener listener)
         throws IOException

Asynchronously sends a GET request PDU to the given target. The response is then returned by calling the supplied ResponseListener instance.

Parameters:

pdu - the PDU instance to send.

target - the Target instance representing the target SNMP engine where to send the pdu.

userHandle - an user defined handle that is returned when the request is returned via the listener object.

listener - a ResponseListener instance that is called when pdu is a confirmed PDU and the request is either answered or timed out.

Throws:

IOException - if the PDU cannot be sent to the target.

Since:

1.1

getNext

public ResponseEvent getNext(PDU pdu,
                             Target target)
                      throws IOException

Sends a GETNEXT request to a target. This method sets the PDU's type to PDU.GETNEXT and then sends a synchronous request to the supplied target. This method is a convenience wrapper for the send(PDU pdu, Target target) method.

Parameters:

pdu - a PDU instance. For SNMPv3 messages, the supplied PDU instance has to be a ScopedPDU instance.

target - the Target instance representing the target SNMP engine where to send the pdu.

Returns:

the received response encapsulated in a ResponseEvent instance. To obtain the received response PDU call ResponseEvent.getResponse(). If the request timed out, that method will return null.

Throws:

IOException - if the PDU cannot be sent to the target.

Since:

1.1

getNext

public void getNext(PDU pdu,
                    Target target,
                    Object userHandle,
                    ResponseListener listener)
             throws IOException

Asynchronously sends a GETNEXT request PDU to the given target. The response is then returned by calling the supplied ResponseListener instance.

Parameters:

pdu - the PDU instance to send.

target - the Target instance representing the target SNMP engine where to send the pdu.

userHandle - an user defined handle that is returned when the request is returned via the listener object.

listener - a ResponseListener instance that is called when pdu is a confirmed PDU and the request is either answered or timed out.

Throws:

IOException - if the PDU cannot be sent to the target.

Since:

1.1

getBulk

public ResponseEvent getBulk(PDU pdu,
                             Target target)
                      throws IOException

Sends a GETBULK request to a target. This method sets the PDU's type to PDU.GETBULK and then sends a synchronous request to the supplied target. This method is a convenience wrapper for the send(PDU pdu, Target target) method.

Parameters:

pdu - a PDU instance. For SNMPv3 messages, the supplied PDU instance has to be a ScopedPDU instance.

target - the Target instance representing the target SNMP engine where to send the pdu.

Returns:

the received response encapsulated in a ResponseEvent instance. To obtain the received response PDU call ResponseEvent.getResponse(). If the request timed out, that method will return null.

Throws:

IOException - if the PDU cannot be sent to the target.

Since:

1.1

getBulk

public void getBulk(PDU pdu,
                    Target target,
                    Object userHandle,
                    ResponseListener listener)
             throws IOException

Asynchronously sends a GETBULK request PDU to the given target. The response is then returned by calling the supplied ResponseListener instance.

Parameters:

pdu - the PDU instance to send.

target - the Target instance representing the target SNMP engine where to send the pdu.

userHandle - an user defined handle that is returned when the request is returned via the listener object.

listener - a ResponseListener instance that is called when pdu is a confirmed PDU and the request is either answered or timed out.

Throws:

IOException - if the PDU cannot be sent to the target.

Since:

1.1

inform

public ResponseEvent inform(PDU pdu,
                            Target target)
                     throws IOException

Sends an INFORM request to a target. This method sets the PDU's type to PDU.INFORM and then sends a synchronous request to the supplied target. This method is a convenience wrapper for the send(PDU pdu, Target target) method.

Parameters:

pdu - a PDU instance. For SNMPv3 messages, the supplied PDU instance has to be a ScopedPDU instance.

target - the Target instance representing the target SNMP engine where to send the pdu.

Returns:

the received response encapsulated in a ResponseEvent instance. To obtain the received response PDU call ResponseEvent.getResponse(). If the request timed out, that method will return null.

Throws:

IOException - if the inform request could not be send to the specified target.

Since:

1.1

inform

public void inform(PDU pdu,
                   Target target,
                   Object userHandle,
                   ResponseListener listener)
            throws IOException

Asynchronously sends an INFORM request PDU to the given target. The response is then returned by calling the supplied ResponseListener instance.

Parameters:

pdu - the PDU instance to send.

target - the Target instance representing the target SNMP engine where to send the pdu.

userHandle - an user defined handle that is returned when the request is returned via the listener object.

listener - a ResponseListener instance that is called when pdu is a confirmed PDU and the request is either answered or timed out.

Throws:

IOException - if the PDU cannot be sent to the target.

Since:

1.1

trap

public void trap(PDUv1 pdu,
                 Target target)
          throws IOException

Sends a SNMPv1 trap to a target. This method sets the PDU's type to PDU.V1TRAP and then sends it to the supplied target. This method is a convenience wrapper for the send(PDU pdu, Target target) method.

Parameters:

pdu - a PDUv1 instance.

target - the Target instance representing the target SNMP engine where to send the pdu. The selected SNMP protocol version for the target must be SnmpConstants.version1.

Throws:

IOException - if the trap cannot be sent.

Since:

1.1

notify

public void notify(PDU pdu,
                   Target target)
            throws IOException

Sends a SNMPv2c or SNMPv3 notification to a target. This method sets the PDU's type to PDU.NOTIFICATION and then sends it to the supplied target. This method is a convenience wrapper for the send(PDU pdu, Target target) method.

Parameters:

pdu - a PDUv1 instance.

target - the Target instance representing the target SNMP engine where to send the pdu. The selected SNMP protocol version for the target must be SnmpConstants.version2c or SnmpConstants.version2c.

Throws:

IOException - if the notification cannot be sent.

Since:

1.1

set

public ResponseEvent set(PDU pdu,
                         Target target)
                  throws IOException

Sends a SET request to a target. This method sets the PDU's type to PDU.SET and then sends a synchronous request to the supplied target.

Parameters:

pdu - a PDU instance. For SNMPv3 messages, the supplied PDU instance has to be a ScopedPDU instance.

target - the Target instance representing the target SNMP engine where to send the pdu.

Returns:

the received response encapsulated in a ResponseEvent instance. To obtain the received response PDU call ResponseEvent.getResponse(). If the request timed out, that method will return null.

Throws:

IOException - if the PDU cannot be sent to the target.

Since:

1.1

set

public void set(PDU pdu,
                Target target,
                Object userHandle,
                ResponseListener listener)
         throws IOException

Asynchronously sends a SET request PDU to the given target. The response is then returned by calling the supplied ResponseListener instance.

Parameters:

pdu - the PDU instance to send.

target - the Target instance representing the target SNMP engine where to send the pdu.

userHandle - an user defined handle that is returned when the request is returned via the listener object.

listener - a ResponseListener instance that is called when pdu is a confirmed PDU and the request is either answered or timed out.

Throws:

IOException - if the PDU cannot be sent to the target.

Since:

1.1

send

public ResponseEvent send(PDU pdu,
                          Target target)
                   throws IOException

Description copied from interface: Session

Sends a PDU to the given target and returns the received response PDU.

Specified by:

send in interface Session

Parameters:

pdu - the PDU to send.

target - the Target instance that specifies how and where to send the PDU.

Returns:

the received response encapsulated in a ResponseEvent instance. To obtain the received response PDU call ResponseEvent.getResponse(). If the request timed out, that method will return null. If the sent pdu is an unconfirmed PDU (notification, response, or report), then null will be returned.

Throws:

IOException - if the message could not be send.

send

public ResponseEvent send(PDU pdu,
                          Target target,
                          TransportMapping transport)
                   throws IOException

Sends a PDU to the given target and if the PDU is a confirmed request, then the received response is returned synchronously.

Specified by:

send in interface Session

Parameters:

pdu - a PDU instance. When sending a SNMPv1 trap PDU, the supplied PDU instance must be a PDUv1. For all types of SNMPv3 messages, the supplied PDU instance has to be a ScopedPDU instance.

target - the Target instance representing the target SNMP engine where to send the pdu.

transport - specifies the TransportMapping to be used when sending the PDU. If transport is null, the associated message dispatcher will try to determine the transport mapping by the target's address.

Returns:

the received response encapsulated in a ResponseEvent instance. To obtain the received response PDU call ResponseEvent.getResponse(). If the request timed out, that method will return null. If the sent pdu is an unconfirmed PDU (notification, response, or report), then null will be returned.

Throws:

IOException - if the message could not be sent.

See Also:

PDU, ScopedPDU, PDUv1

send

public void send(PDU pdu,
                 Target target,
                 Object userHandle,
                 ResponseListener listener)
          throws IOException

Description copied from interface: Session

Asynchronously sends a PDU to the given target. The response is then returned by calling the supplied ResponseListener instance.

Specified by:

send in interface Session

Parameters:

pdu - the PDU instance to send.

target - the Target instance representing the target SNMP engine where to send the pdu.

userHandle - an user defined handle that is returned when the request is returned via the listener object.

listener - a ResponseListener instance that is called when pdu is a confirmed PDU and the request is either answered or timed out.

Throws:

IOException - if the message could not be send.

send

public void send(PDU pdu,
                 Target target,
                 TransportMapping transport,
                 Object userHandle,
                 ResponseListener listener)
          throws IOException

Description copied from interface: Session

Asynchronously sends a PDU to the given target. The response is then returned by calling the supplied ResponseListener instance.

Specified by:

send in interface Session

Parameters:

pdu - the PDU instance to send.

target - the Target instance representing the target SNMP engine where to send the pdu.

transport - specifies the TransportMapping to be used when sending the PDU. If transport is null, the associated message dispatcher will try to determine the transport mapping by the target's address.

userHandle - an user defined handle that is returned when the request is returned via the listener object.

listener - a ResponseListener instance that is called when pdu is a confirmed PDU and the request is either answered or timed out.

Throws:

IOException - if the message could not be send.

sendMessage

protected PduHandle sendMessage(PDU pdu,
                                Target target,
                                TransportMapping transport,
                                PduHandleCallback<PDU> pduHandleCallback)
                         throws IOException

Actually sends a PDU to a target and returns a handle for the sent PDU.

Parameters:

pdu - the PDU instance to be sent.

target - a Target instance denoting the target SNMP entity.

transport - the (optional) transport mapping to be used to send the request. If transport is null a suitable transport mapping is determined from the target address.

pduHandleCallback - callback for newly created PDU handles before the request is sent out.

Returns:

PduHandle that uniquely identifies the sent PDU for further reference.

Throws:

IOException - if the transport fails to send the PDU or the if the message cannot be BER encoded.

lookupTransportMapping

protected TransportMapping lookupTransportMapping(Target target)

cancel

public void cancel(PDU request,
                   ResponseListener listener)

Description copied from interface: Session

Cancels an asynchronous request. Any asynchronous request must be canceled when the supplied response listener is being called, even if the ResponseEvent indicates an error.

Specified by:

cancel in interface Session

Parameters:

request - a request PDU as sent via Session.send(PDU pdu, Target target, Object userHandle, ResponseListener listener) or any .

listener - a ResponseListener instance.

setLocalEngine

public void setLocalEngine(byte[] engineID,
                           int engineBoots,
                           int engineTime)

Sets the local engine ID for the SNMP entity represented by this Snmp instance. This is a convenience method that sets the local engine ID in the associated MPv3 and USM.

Parameters:

engineID - a byte array containing the local engine ID. The length and content has to comply with the constraints defined in the SNMP-FRAMEWORK-MIB.

engineBoots - the number of boots of this SNMP engine (zero based).

engineTime - the number of seconds since the value of engineBoots last changed.

See Also:

MPv3, USM

getLocalEngineID

public byte[] getLocalEngineID()

Gets the local engine ID if the MPv3 is available, otherwise a runtime exception is thrown.

Returns:

byte[] the local engine ID.

discoverAuthoritativeEngineID

public byte[] discoverAuthoritativeEngineID(Address address,
                                            long timeout)

Discovers the engine ID of the SNMPv3 entity denoted by the supplied address. This method does not need to be called for normal operation, because SNMP4J automatically discovers authoritative engine IDs and also automatically synchronize engine time values.

For this method to operate successfully, the discover engine IDs flag in USM must be true (which is the default).

Parameters:

address - an Address instance representing the transport address of the SNMPv3 entity for which its authoritative engine ID should be discovered.

timeout - the maximum time in milliseconds to wait for a response.

Returns:

a byte array containing the authoritative engine ID or null if it could not be discovered.

See Also:

USM.setEngineDiscoveryEnabled(boolean enableEngineDiscovery)

getUSM

public USM getUSM()

Gets the User Based Security Model (USM). This is a convenience method that uses the MPv3.getSecurityModel(int) method of the associated MPv3 instance to get the USM.

Returns:

the USM instance associated with the MPv3 bound to this Snmp instance, or null otherwise.

getMessageProcessingModel

public MessageProcessingModel getMessageProcessingModel(int messageProcessingModel)

Gets the message processing model for the supplied ID.

Parameters:

messageProcessingModel - a mesage processing model ID as defined in MessageProcessingModel.

Returns:

MessageProcessingModel a MessageProcessingModel if messageProcessingModel has been registered with the message dispatcher associated with this SNMP session.

processPdu

public void processPdu(CommandResponderEvent event)

Process an incoming request or notification PDU.

Specified by:

processPdu in interface CommandResponder

Parameters:

event - a CommandResponderEvent with the decoded incoming PDU as dispatched to this method call by the associated message dispatcher.

isContextEngineIdDiscoveryDisabled

public boolean isContextEngineIdDiscoveryDisabled()

Checks whether RFC5343 based context engine ID discovery is disabled or not. The default value is false.

Returns:

true if context engine ID discovery is disabled.

Since:

2.0

setContextEngineIdDiscoveryDisabled

public void setContextEngineIdDiscoveryDisabled(boolean contextEngineIdDiscoveryDisabled)

Sets the RFC5343 based context engine ID discovery. The default value is false.

Parameters:

contextEngineIdDiscoveryDisabled - true to disable context engine ID discovery, false to enable context engine ID discovery.

Since:

2.0

resendRequest

protected boolean resendRequest(org.snmp4j.Snmp.PendingRequest request,
                                PDU response)

handleInternalResponse

protected void handleInternalResponse(PDU response,
                                      PDU pdu,
                                      Address target)

removeCommandResponder

public void removeCommandResponder(CommandResponder listener)

Removes a CommandResponder from this SNMP session.

Parameters:

listener - a previously added CommandResponder instance.

addCommandResponder

public void addCommandResponder(CommandResponder listener)

Adds a CommandResponder to this SNMP session. The command responder will then be informed about incoming SNMP PDUs of any kind that are not related to any outstanding requests of this SNMP session.

Parameters:

listener - the CommandResponder instance to be added.

fireProcessPdu

protected void fireProcessPdu(CommandResponderEvent event)

Fires a CommandResponderEvent event to inform listeners about a received PDU. If a listener has marked the event as processed further listeners will not be informed about the event.

Parameters:

event - a CommandResponderEvent.

getTimeoutModel

public TimeoutModel getTimeoutModel()

Gets the timeout model associated with this SNMP session.

Returns:

a TimeoutModel instance (never null).

See Also:

setTimeoutModel(TimeoutModel timeoutModel)

getReportHandler

public Snmp.ReportHandler getReportHandler()

Returns the report handler which is used internally to process reports received from command responders.

Returns:

the ReportHandler instance.

Since:

1.6

getCounterSupport

public CounterSupport getCounterSupport()

Gets the counter support for Snmp related counters. These are for example: snmp4jStatsRequestTimeouts, snmp4jStatsRequestTimeouts, snmp4jStatsRequestWaitTime

Returns:

the counter support if available. If the SNMP4JSettings.getSnmp4jStatistics() value is SNMP4JSettings.Snmp4jStatistics.none then no counter support will be created and no statistics will be collected.

Since:

2.4.2

setCounterSupport

public void setCounterSupport(CounterSupport counterSupport)

Sets the counter support instance to handle counter events on behalf of this Snmp instance.

Parameters:

counterSupport - the counter support instance that collects the statistics events created by this Snmp instance. See also getCounterSupport().

Since:

2.4.2

setTimeoutModel

public void setTimeoutModel(TimeoutModel timeoutModel)

Sets the timeout model for this SNMP session. The default timeout model sends retries whenever the time specified by the timeout parameter of the target has elapsed without a response being received for the request. By specifying a different timeout model this behaviour can be changed.

Parameters:

timeoutModel - a TimeoutModel instance (must not be null).

setReportHandler

public void setReportHandler(Snmp.ReportHandler reportHandler)

Sets the report handler and overrides the default report handler.

Parameters:

reportHandler - a ReportHandler instance which must not be null.

Since:

1.6

getPendingSyncRequestCount

public int getPendingSyncRequestCount()

Gets the number of currently pending synchronous requests.

Returns:

the size of the synchronous request queue.

Since:

2.4.2

getPendingAsyncRequestCount

public int getPendingAsyncRequestCount()

Gets the number of currently pending asynchronous requests.

Returns:

the size of the asynchronous request queue.

Since:

2.4.2

closeTransportMapping

protected void closeTransportMapping(TransportMapping tm)