uk.co.westhawk.snmp.stack

Class Pdu

java.lang.Object

java.util.Observable

uk.co.westhawk.snmp.stack.Pdu

Direct Known Subclasses:

GetBulkPdu, GetNextPdu, GetPdu, InformPdu, MultiResponsePdu, ReportPdu, ResponsePdu, SetPdu, TrapPduv1, TrapPduv2

public abstract class Pdu
extends java.util.Observable

This class represents the ASN PDU object, this is the equivalent of a GetRequest PDU.

Version:

$Revision$ $Date$

Author:

Tim Panton

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	added
protected boolean	answered
protected SnmpContextBasisFace	context
protected byte[]	encodedPacket
protected int	errind
protected int	errstat
protected byte	msg_type
protected java.util.Vector	reqVarbinds
protected java.util.Vector	respVarbinds
protected java.lang.Integer	snmpv3MsgId

Constructor Summary

Constructors

Constructor and Description
Pdu(SnmpContextBasisFace con) Constructor.

Method Summary

Modifier and Type	Method and Description
void	addOid(AsnObjectId oid) Adds an OID (object identifier) to the PDU.
void	addOid(AsnObjectId oid, AsnObject val) Adds an OID (object identifier) to the PDU and the value that has to be set.
void	addOid(java.lang.String oid) Adds an OID (object identifier) to the PDU.
void	addOid(java.lang.String oid, AsnObject val) Adds an OID (object identifier) to the PDU and the value that has to be set.
void	addOid(varbind var) Adds an OID (object identifier) to the PDU.
protected void	addToTrans() Adds the PDU to its transmitter.
SnmpContextBasisFace	getContext() Returns the context of this PDU.
int	getErrorIndex() Returns the error index.
int	getErrorStatus() Returns the error status as indicated by the error-status field in the reponse PDU.
java.lang.String	getErrorStatusString() Returns the string representation of the error status.
byte	getMsgType() Returns the message type, this will indicate what kind of request we are dealing with.
int	getReqId() Returns the request id of the PDU.
varbind[]	getRequestVarbinds() Returns a copy of the varbinds used to build the request.
varbind[]	getResponseVarbinds() Returns a copy of the varbinds received in the response.
int[]	getRetryIntervals()
protected boolean	isExpectingResponse() Returns whether or not this type of PDU is expecting some kind of response.
boolean	isTimedOut() Returns whether or not this PDU is timed out, i.e. it did not get a response.
protected void	new_value(int n, varbind res) The value of the response is set.
void	notifyObservers(java.lang.Object arg) Notify all observers.
protected java.lang.StringBuffer	printVars(java.lang.String title, java.util.Vector vars) Returns the string representation of the varbinds of the PDU.
boolean	send() Sends the PDU.
protected boolean	send(int error_status, int error_index) Sends the PDU.
boolean	send(java.lang.String com) Deprecated. Community name has moved to SnmpContext. Use SnmpContext.setCommunity(String).
protected boolean	sendme() Sends the actual packet and updates the retries.
protected void	setErrorIndex(int ind) Sets the error index, this indicates which of the OIDs went wrong.
protected void	setErrorStatus(int err) Sets the error status, indicating what went wrong.
protected void	setErrorStatus(int err, PduException exc) Sets the error status and the exception, indicating what went wrong.
protected void	setMsgType(byte type) Sets the message type, this will indicate what kind of request we are dealing with.
void	setRetryIntervals(int[] rinterval) Sets the retry intervals of the PDU.
protected void	tell_them() This method notifies all observers.
java.lang.String	toString() Returns the string representation of the PDU.
protected java.lang.String	toString(boolean withRespVars) Returns the string representation of the PDU with or without the response varbinds.
boolean	waitForSelf() This method will wait until the answer is received, instead of continue with other stuff.

Methods inherited from class java.util.Observable

addObserver, clearChanged, countObservers, deleteObserver, deleteObservers, hasChanged, notifyObservers, setChanged

Methods inherited from class java.lang.Object

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

Field Detail

reqVarbinds

protected java.util.Vector reqVarbinds

respVarbinds

protected java.util.Vector respVarbinds

encodedPacket

protected byte[] encodedPacket

context

protected SnmpContextBasisFace context

added

protected boolean added

msg_type

protected byte msg_type

snmpv3MsgId

protected java.lang.Integer snmpv3MsgId

errstat

protected int errstat

errind

protected int errind

answered

protected boolean answered

Constructor Detail

Pdu

public Pdu(SnmpContextBasisFace con)

Constructor.

Parameters:

con - The context of the PDU

See Also:

SnmpContext, SnmpContextv2c, SnmpContextv3

Method Detail

new_value

protected void new_value(int n,
                         varbind res)

The value of the response is set. This will be called by Pdu.fillin().

tell_them

protected void tell_them()

This method notifies all observers. This will be called by Pdu.fillin().

The Object to the update() method of the Observer will be a varbind, unless an exception occurred. In the case of an exception, that exception will be passed. So watch out casting!

getContext

public SnmpContextBasisFace getContext()

Returns the context of this PDU.

Returns:

The context

setRetryIntervals

public void setRetryIntervals(int[] rinterval)

Sets the retry intervals of the PDU. The length of the array corresponds with the number of retries. Each entry in the array is the number of milliseconds of each try.

If used, please set before sending!

The default is {500, 1000, 2000, 5000, 5000}. It is good practice to make the interval bigger with each retry, if the numbers are the same the chance of collision is higher.

Parameters:

rinterval - The interval in msec of each retry

getRetryIntervals

public int[] getRetryIntervals()

send

public boolean send()
             throws java.io.IOException,
                    PduException

Sends the PDU. Note that all properties of the context have to be set before this point.

Throws:

java.io.IOException

PduException

send

protected boolean send(int error_status,
                       int error_index)
                throws java.io.IOException,
                       PduException

Sends the PDU. This method accommodates the GetBulk request.

Parameters:

error_status - The value of the error_status field.

error_index - The value of the error_index field.

Throws:

java.io.IOException

PduException

See Also:

send()

addToTrans

protected void addToTrans()

Adds the PDU to its transmitter. The transmitter is the thread that will be sent the PDU and then waits for the answer.

See Also:

send()

sendme

protected boolean sendme()

Sends the actual packet and updates the retries.

See Also:

AbstractSnmpContext.sendPacket(byte[] p)

send

public boolean send(java.lang.String com)
             throws java.io.IOException,
                    PduException

Deprecated. Community name has moved to SnmpContext. Use SnmpContext.setCommunity(String).

Sends the PDU. For backwards compatibility only. Please use send() instead. The community name will be passed to the SnmpContext. If using SnmpContextv3, the community name will be ignored.

Parameters:

com - The community name of the PDU in SNMPv1 and SNMPv2c.

Throws:

java.io.IOException

PduException

See Also:

SnmpContext.setCommunity(java.lang.String), send()

addOid

public void addOid(java.lang.String oid)

Adds an OID (object identifier) to the PDU. The OID indicates which MIB variable we request for or which MIB variable should be set.

Parameters:

oid - The oid

See Also:

addOid(varbind), varbind

addOid

public void addOid(AsnObjectId oid)

Adds an OID (object identifier) to the PDU. The OID indicates which MIB variable we request for or which MIB variable should be set.

Parameters:

oid - The oid

Since:

4_12

See Also:

addOid(varbind), varbind

addOid

public void addOid(java.lang.String oid,
                   AsnObject val)

Adds an OID (object identifier) to the PDU and the value that has to be set. This method has moved from SetPdu to this class in version 4_12.

Parameters:

oid - The oid

val - The value

Since:

4_12

See Also:

addOid(java.lang.String), varbind

addOid

public void addOid(AsnObjectId oid,
                   AsnObject val)

Adds an OID (object identifier) to the PDU and the value that has to be set.

Thanks to Eli Bishop (eli@graphesthesia.com) for the suggestion.

Parameters:

oid - The oid

val - The value

Since:

4_12

See Also:

addOid(java.lang.String), varbind

addOid

public void addOid(varbind var)

Adds an OID (object identifier) to the PDU.

Parameters:

var - The varbind

See Also:

addOid(String)

getRequestVarbinds

public varbind[] getRequestVarbinds()

Returns a copy of the varbinds used to build the request.

Returns:

the request varbinds of this PDU.

getResponseVarbinds

public varbind[] getResponseVarbinds()
                              throws PduException

Returns a copy of the varbinds received in the response. If there was no response (yet), null will be returned.

Returns:

the response varbinds of this PDU.

Throws:

PduException - An agent or decoding exception occurred whilst receiving the response.

See Also:

getErrorStatus(), notifyObservers(java.lang.Object)

getReqId

public int getReqId()

Returns the request id of the PDU.

Returns:

The ID

getErrorIndex

public int getErrorIndex()

Returns the error index. The error index indicates which of the OIDs went wrong.

Returns:

the error index

See Also:

getErrorStatus()

getErrorStatus

public int getErrorStatus()

Returns the error status as indicated by the error-status field in the reponse PDU. The error index will indicated which OID caused the error. In case of a decoding exception the error status will be set to one of the decoding errors:

• SnmpConstants.SNMP_ERR_DECODING_EXC.
• SnmpConstants.SNMP_ERR_DECODINGASN_EXC.
• SnmpConstants.SNMP_ERR_DECODINGPKTLNGTH_EXC.

The actual exception will be passed to your update(Observable ob, Object arg) method via the the parameter arg.

Returns:

the error status

See Also:

notifyObservers(java.lang.Object), getResponseVarbinds(), SnmpConstants.SNMP_ERR_NOERROR, SnmpConstants.SNMP_ERR_DECODING_EXC, SnmpConstants.SNMP_ERR_DECODINGASN_EXC, SnmpConstants.SNMP_ERR_DECODINGPKTLNGTH_EXC, getErrorStatusString(), getErrorIndex()

getErrorStatusString

public java.lang.String getErrorStatusString()

Returns the string representation of the error status.

Returns:

the error string

See Also:

getErrorStatus()

isTimedOut

public boolean isTimedOut()

Returns whether or not this PDU is timed out, i.e. it did not get a response. Its errorStatus will be set to AsnObject.SNMP_ERR_GENERR.

Note that a SNMP agent can respond with an errorStatus of AsnObject.SNMP_ERR_GENERR as well, so getting a AsnObject.SNMP_ERR_GENERR does not necessarily mean that the request is timed out!

Returns:

true is the PDU was timed out

See Also:

getErrorStatus(), SnmpConstants.SNMP_ERR_GENERR

waitForSelf

public boolean waitForSelf()

This method will wait until the answer is received, instead of continue with other stuff.

toString

public java.lang.String toString()

Returns the string representation of the PDU.

Overrides:

toString in class java.lang.Object

Returns:

The string of the PDU

toString

protected java.lang.String toString(boolean withRespVars)

Returns the string representation of the PDU with or without the response varbinds.

Parameters:

withRespVars - Include the response varbinds or not

Returns:

The string of the PDU

printVars

protected java.lang.StringBuffer printVars(java.lang.String title,
                                           java.util.Vector vars)

Returns the string representation of the varbinds of the PDU.

Since:

4_14

See Also:

toString(boolean)

getMsgType

public byte getMsgType()

Returns the message type, this will indicate what kind of request we are dealing with. By default it will be set to the GET_REQ_MSG

Returns:

The message type

setMsgType

protected void setMsgType(byte type)

Sets the message type, this will indicate what kind of request we are dealing with. By default it will be set to the GET_REQ_MSG

Parameters:

type - The message type

setErrorStatus

protected void setErrorStatus(int err)

Sets the error status, indicating what went wrong.

Parameters:

err - the error status

See Also:

getErrorIndex(), getErrorStatusString(), getErrorStatus()

setErrorStatus

protected void setErrorStatus(int err,
                              PduException exc)

Sets the error status and the exception, indicating what went wrong.

Parameters:

err - the error status

exc - the PDU Exception that was thrown whilst decoding

See Also:

getErrorIndex(), getErrorStatusString(), getErrorStatus()

setErrorIndex

protected void setErrorIndex(int ind)

Sets the error index, this indicates which of the OIDs went wrong.

Parameters:

ind - the error index

See Also:

setErrorStatus(int), getErrorIndex()

isExpectingResponse

protected boolean isExpectingResponse()

Returns whether or not this type of PDU is expecting some kind of response. This method is used in AbstractSnmpContext to help determine whether or not to start a thread that listens for a response when sending this PDU. The default is true.

Returns:

true if a response is expected, false if not.

Since:

4_14

notifyObservers

public void notifyObservers(java.lang.Object arg)

Notify all observers. If a decoding exception had occurred, the argument will be replaced with the exception.

In the case of an exception, the error status will be set to one of the decoding errors (see getErrorStatus) and passed as the parameter arg in the update(Observable obs, Object arg) method.

Overrides:

notifyObservers in class java.util.Observable

Parameters:

arg - The argument passed to update, can be a PduException.

Since:

4.5

See Also:

SnmpConstants.SNMP_ERR_DECODING_EXC, getErrorStatus(), getResponseVarbinds()