Package uk.co.westhawk.snmp.stack

Class SnmpContextPool

java.lang.Object

uk.co.westhawk.snmp.stack.SnmpContextPool

All Implemented Interfaces:

SnmpContextBasisFace, SnmpContextFace

Direct Known Subclasses:

SnmpContextv2cPool

public class SnmpContextPool
extends Object
implements SnmpContextFace

This class contains the pool of SNMP v1 contexts. This class reuses the existings contexts instead of creating a new one every time.

Every time a property changes the pool is checked for a SnmpContext context that matches all the new properties of this class. If no such context exists, a new one is made. The PDUs associated with the old context remain associated with the old context.

A counter indicates the number of times the context is referenced. The counter is decreased when destroy() is called. When the counter reaches zero, the context is released.

Note that because the underlying context can change when a property is changed and the PDUs remain associated with the old context, all properties have to be set BEFORE a PDU is sent.

Thanks to Seon Lee (slee@virtc.com) for reporting thread safety problems.

Version:

$Revision: 3.22 $ $Date: 2009/03/05 13:27:41 $

Author:

Birgit Arkesteijn

See Also:

• SnmpContext
• SnmpContextv2cPool
• SnmpContextv3Pool

Field Summary

Fields inherited from interface uk.co.westhawk.snmp.stack.SnmpContextBasisFace

DEFAULT_PORT, MAXPDU, MSS, STANDARD_SOCKET, TCP_SOCKET

Fields inherited from interface uk.co.westhawk.snmp.stack.SnmpContextFace

DEFAULT_COMMUNITY

Constructor Summary

Constructors

Constructor	Description
SnmpContextPool(String host, int port)	Constructor, using the Standard socket.
SnmpContextPool(String host, int port, String typeSocket)	Constructor.
SnmpContextPool(String host, int port, String comm, String typeSocket)	Constructor.
SnmpContextPool(String host, int port, String comm, String bindAddress, String typeSocket)	Constructor.

Method Summary

Modifier and Type	Method	Description
boolean	addPdu(Pdu pdu)	Adds a PDU to the context.
void	addRequestPduListener(RequestPduListener l)	Adds the specified request pdu listener to receive PDUs on the default request pdu port 161 from the host that matches this context.
void	addRequestPduListener(RequestPduListener l, int port)	Adds the specified request pdu listener to receive PDUs on the specified port from the host that matches this context.
void	addRequestPduListener(RequestPduListener l, ListeningContextPool lcontext)	Adds the specified request pdu listener to receive PDUs on the specified listening context that matches this context.
void	addTrapListener(TrapListener l)	Adds the specified trap listener.
void	addTrapListener(TrapListener l, int port)	Adds the specified trap listener to receive traps on the specified port from the host that matches this context.
void	addTrapListener(TrapListener l, ListeningContextPool lcontext)	Adds the specified trap listener to receive traps on the specified listening context that matches this context.
Object	clone()	This method is not supported.
void	destroy()	Releases the resources held by this context.
void	destroyPool()	Destroys all the contexts (v1 and v2c) in the pool and empties the pool.
void	dumpContexts(String title)	Dumps the pool of contexts.
byte[]	encodePacket(byte msg_type, int rId, int errstat, int errind, Enumeration ve, Object obj)	Encodes a PDU packet.
String	getBindAddress()	Returns the local bind address.
String	getCommunity()	Returns the community name.
String	getHashKey()	Returns the hash key.
String	getHost()	Returns the host.
int	getPort()	Returns the port number.
String	getReceivedFromHostAddress()	Returns the IP address string aaa.bbb.ccc.ddd (IPv4) or a:b:c:d:e:f:g:h (IPv6) of the (latest) host the packets where received from.
String	getSendToHostAddress()	Returns the IP address string aaa.bbb.ccc.ddd (IPv4) or a:b:c:d:e:f:g:h (IPv6) of the host the packets where sent to.
String	getTypeSocket()	Returns the type of socket.
int	getVersion()	Returns the SNMP version of the context.
boolean	isDestroyed()	Returns whether or not this context has been destroyed.
Pdu	processIncomingPdu(byte[] message)	Processes the incoming PDU with the current context.
boolean	removePdu(int requestId)	Removes a PDU from the context.
void	removeRequestPduListener(RequestPduListener l)	Removes the specified request pdu listener from listening for packets on the default request pdu port 161.
void	removeRequestPduListener(RequestPduListener l, int port)	Removes the specified request pdu listener from listening for packets on the specified port.
void	removeRequestPduListener(RequestPduListener l, ListeningContextPool lcontext)	Removes the specified request pdu listener from listening for packets on the specified listening context.
void	removeTrapListener(TrapListener l)	Removes the specified trap listener.
void	removeTrapListener(TrapListener l, int port)	Removes the specified trap listener from listening for packets on the specified port.
void	removeTrapListener(TrapListener l, ListeningContextPool lcontext)	Removes the specified trap listener from listening for packets on the specified listening context.
void	sendPacket(byte[] packet)	Sends an encoded PDU.
void	setCommunity(String newCommunity)	Sets the community name.
String	toString()	Returns a string representation of the object.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Details

SnmpContextPool

public SnmpContextPool(String host,
 int port)
                throws IOException

Constructor, using the Standard socket.

Parameters:

host - The host to which the PDU will be sent

port - The port where the SNMP server will be

Throws:

IOException

See Also:

• SnmpContext(String, int)

SnmpContextPool

public SnmpContextPool(String host,
 int port,
 String typeSocket)
                throws IOException

Constructor. Parameter typeSocket should be either STANDARD_SOCKET, TCP_SOCKET or a fully qualified classname.

Parameters:

host - The host to which the PDU will be sent

port - The port where the SNMP server will be

typeSocket - The type of socket to use.

Throws:

IOException

See Also:

• SnmpContext(String, int, String)
• SnmpContextBasisFace.STANDARD_SOCKET
• SnmpContextBasisFace.TCP_SOCKET

SnmpContextPool

public SnmpContextPool(String host,
 int port,
 String comm,
 String typeSocket)
                throws IOException

Constructor. Parameter typeSocket should be either STANDARD_SOCKET, TCP_SOCKET or a fully qualified classname.

Parameters:

host - The host to which the PDU will be sent

port - The port where the SNMP server will be

comm - The community name.

typeSocket - The type of socket to use.

Throws:

IOException

Since:

4_12

See Also:

• SnmpContextBasisFace.STANDARD_SOCKET
• SnmpContextBasisFace.TCP_SOCKET

SnmpContextPool

public SnmpContextPool(String host,
 int port,
 String comm,
 String bindAddress,
 String typeSocket)
                throws IOException

Constructor. Parameter typeSocket should be either STANDARD_SOCKET, TCP_SOCKET or a fully qualified classname.

Parameters:

host - The host to which the PDU will be sent

port - The port where the SNMP server will be

comm - The community name.

bindAddress - The local address the server will bind to

typeSocket - The type of socket to use.

Throws:

IOException

Since:

4_14

See Also:

• SnmpContextBasisFace.STANDARD_SOCKET
• SnmpContextBasisFace.TCP_SOCKET

Method Details

getVersion

public int getVersion()

Description copied from interface: SnmpContextBasisFace

Returns the SNMP version of the context.

Specified by:

getVersion in interface SnmpContextBasisFace

Returns:

The version

See Also:

• SnmpConstants.SNMP_VERSION_1
• SnmpConstants.SNMP_VERSION_2c
• SnmpConstants.SNMP_VERSION_3

getHost

public String getHost()

Description copied from interface: SnmpContextBasisFace

Returns the host.

Specified by:

getHost in interface SnmpContextBasisFace

Returns:

The host

getPort

public int getPort()

Description copied from interface: SnmpContextBasisFace

Returns the port number.

Specified by:

getPort in interface SnmpContextBasisFace

Returns:

The port no

getBindAddress

public String getBindAddress()

Description copied from interface: SnmpContextBasisFace

Returns the local bind address. If bindAddress is null, then the system will pick up a valid local address to bind the socket.

Specified by:

getBindAddress in interface SnmpContextBasisFace

Returns:

The local bind address

getTypeSocket

public String getTypeSocket()

Description copied from interface: SnmpContextBasisFace

Returns the type of socket.

Specified by:

getTypeSocket in interface SnmpContextBasisFace

Returns:

The type of socket

See Also:

• SnmpContextBasisFace.STANDARD_SOCKET
• SnmpContextBasisFace.TCP_SOCKET

getSendToHostAddress

public String getSendToHostAddress()

Description copied from interface: SnmpContextBasisFace

Returns the IP address string aaa.bbb.ccc.ddd (IPv4) or a:b:c:d:e:f:g:h (IPv6) of the host the packets where sent to.

Specified by:

getSendToHostAddress in interface SnmpContextBasisFace

Returns:

The IP address of the host the packets where sent to.

See Also:

• ContextSocketFace.getSendToHostAddress()

getReceivedFromHostAddress

public String getReceivedFromHostAddress()

Description copied from interface: SnmpContextBasisFace

Returns the IP address string aaa.bbb.ccc.ddd (IPv4) or a:b:c:d:e:f:g:h (IPv6) of the (latest) host the packets where received from.

Specified by:

getReceivedFromHostAddress in interface SnmpContextBasisFace

Returns:

The IP address of the (latest) host the packets where received from.

See Also:

• ContextSocketFace.getReceivedFromHostAddress()

getCommunity

public String getCommunity()

Description copied from interface: SnmpContextFace

Returns the community name.

Specified by:

getCommunity in interface SnmpContextFace

setCommunity

public void setCommunity(String newCommunity)

Description copied from interface: SnmpContextFace

Sets the community name. This community name will be used for all PDUs sent with this context. The default community name is public.

Specified by:

setCommunity in interface SnmpContextFace

See Also:

• SnmpContextFace.DEFAULT_COMMUNITY

addPdu

public boolean addPdu(Pdu pdu)
               throws IOException,
PduException

Description copied from interface: SnmpContextBasisFace

Adds a PDU to the context. This is for internal use only and should NOT be called by the developer. This is called by the the Pdu itself and is added to the interface to cover the different kind of Contexts.

Specified by:

addPdu in interface SnmpContextBasisFace

Parameters:

pdu - the PDU

Returns:

whether the PDU has been successfully added

Throws:

IOException

PduException

removePdu

public boolean removePdu(int requestId)

Description copied from interface: SnmpContextBasisFace

Removes a PDU from the context. This is for internal use only and should NOT be called by the developer. This is called by the the PDU itself and is added to the interface to cover the different kind of Contexts.

Specified by:

removePdu in interface SnmpContextBasisFace

Parameters:

requestId - the PDU request id

Returns:

whether the PDU has been successfully removed

encodePacket

public byte[] encodePacket(byte msg_type,
 int rId,
 int errstat,
 int errind,
 Enumeration ve,
 Object obj)
                    throws IOException,
EncodingException

Encodes a PDU packet.

Specified by:

encodePacket in interface SnmpContextBasisFace

Parameters:

msg_type - The message type

rId - The message id

errstat - The error status

errind - The error index

ve - The varbind list

obj - Additional object (only used in SNMPv3)

Returns:

The encoded packet

Throws:

IOException

EncodingException

sendPacket

public void sendPacket(byte[] packet)

Description copied from interface: SnmpContextBasisFace

Sends an encoded PDU. This is for internal use only and should NOT be called by the developer. This is called by the the PDU itself and is added to the interface to cover the different kind of Contexts.

Specified by:

sendPacket in interface SnmpContextBasisFace

Parameters:

packet - The encoded packet

destroy

public void destroy()

Releases the resources held by this context. This method will decrement the reference counter. When the reference counter reaches zero the actual context is removed from the pool and destroyed.

Specified by:

destroy in interface SnmpContextBasisFace

destroyPool

public void destroyPool()

Destroys all the contexts (v1 and v2c) in the pool and empties the pool. The underlying implementation uses the same hashtable for both the v1 and the v2c contexts.

Since:

4_14

See Also:

• destroy()

isDestroyed

public boolean isDestroyed()

Description copied from interface: SnmpContextBasisFace

Returns whether or not this context has been destroyed.

Specified by:

isDestroyed in interface SnmpContextBasisFace

dumpContexts

public void dumpContexts(String title)

Dumps the pool of contexts. This is for debug purposes.

Parameters:

title - The title of the dump

getHashKey

public String getHashKey()

Returns the hash key. This key is built out of all properties. It serves as key for the hashtable of (v1) contexts.

Specified by:

getHashKey in interface SnmpContextBasisFace

Returns:

The hash key

addTrapListener

public void addTrapListener(TrapListener l)
                     throws IOException

Adds the specified trap listener. The listener will be added to the current context, not to all the contexts in the hashtable.

Specified by:

addTrapListener in interface SnmpContextBasisFace

Parameters:

l - The trap listener

Throws:

IOException

See Also:

• AbstractSnmpContext.addTrapListener(uk.co.westhawk.snmp.event.TrapListener)

removeTrapListener

public void removeTrapListener(TrapListener l)
                        throws IOException

Removes the specified trap listener. The listener will be removed from the current context, not from all the contexts in the hashtable.

Specified by:

removeTrapListener in interface SnmpContextBasisFace

Parameters:

l - The trap listener

Throws:

IOException

See Also:

• AbstractSnmpContext.removeTrapListener(uk.co.westhawk.snmp.event.TrapListener)

addTrapListener

public void addTrapListener(TrapListener l,
 int port)
                     throws IOException

Description copied from interface: SnmpContextBasisFace

Adds the specified trap listener to receive traps on the specified port from the host that matches this context.

The ListeningContext class will do the actual listening for traps. This context will add itself to a ListeningContextPool object and will only pass the event to its listeners if the pdu matches this context and is a trap pdu.

Specified by:

addTrapListener in interface SnmpContextBasisFace

Parameters:

l - The trap listener

port - The port the traps are received on

Throws:

IOException

See Also:

• ListeningContextPool(int, String, String)
• ListeningContextPool.addRawPduListener(RawPduListener)

removeTrapListener

public void removeTrapListener(TrapListener l,
 int port)
                        throws IOException

Description copied from interface: SnmpContextBasisFace

Removes the specified trap listener from listening for packets on the specified port.

The listener will not be removed from all ListeningContext objects that are in the ListeningContextPool. In order to do that, use ListeningContextPool.removeTrapListenerFromPool()

Specified by:

removeTrapListener in interface SnmpContextBasisFace

Parameters:

l - The trap listener

port - The port the traps are received on

Throws:

IOException

See Also:

• ListeningContextPool(int, String, String)
• ListeningContextPool.removeRawPduListener(RawPduListener)
• ListeningContextPool.removeRawPduListenerFromPool(RawPduListener)

addTrapListener

public void addTrapListener(TrapListener l,
 ListeningContextPool lcontext)
                     throws IOException

Description copied from interface: SnmpContextBasisFace

Adds the specified trap listener to receive traps on the specified listening context that matches this context.

The ListeningContext class will do the actual listening for traps. This context will add itself to a ListeningContextPool object and will only pass the event to its listeners if the pdu matches this context and is a trap pdu.

Specified by:

addTrapListener in interface SnmpContextBasisFace

Parameters:

l - The trap listener

lcontext - The listening context

Throws:

IOException

See Also:

• ListeningContextPool(int, String, String)
• ListeningContextPool.addRawPduListener(RawPduListener)

removeTrapListener

public void removeTrapListener(TrapListener l,
 ListeningContextPool lcontext)
                        throws IOException

Description copied from interface: SnmpContextBasisFace

Removes the specified trap listener from listening for packets on the specified listening context.

The listener will not be removed from all ListeningContext objects that are in the ListeningContextPool. In order to do that, use ListeningContextPool.removeTrapListenerFromPool()

Specified by:

removeTrapListener in interface SnmpContextBasisFace

Parameters:

l - The trap listener

lcontext - The listening context

Throws:

IOException

See Also:

• ListeningContextPool(int, String, String)
• ListeningContextPool.removeRawPduListener(RawPduListener)
• ListeningContextPool.removeRawPduListenerFromPool(RawPduListener)

addRequestPduListener

public void addRequestPduListener(RequestPduListener l)
                           throws IOException

Description copied from interface: SnmpContextBasisFace

Adds the specified request pdu listener to receive PDUs on the default request pdu port 161 from the host that matches this context.

The ListeningContext class will do the actual listening for PDUs. This context will add itself to a ListeningContextPool object and will only pass the event to its listeners if the pdu matches this context and is a request pdu.

Don't use the TCP_SOCKET when listening for request PDUs. It doesn't provide functionality to send a response back.

Specified by:

addRequestPduListener in interface SnmpContextBasisFace

Parameters:

l - The request PDU listener

Throws:

IOException

See Also:

• SnmpContextBasisFace.addRequestPduListener(RequestPduListener, int)
• SnmpContextBasisFace.DEFAULT_PORT

removeRequestPduListener

public void removeRequestPduListener(RequestPduListener l)
                              throws IOException

Description copied from interface: SnmpContextBasisFace

Removes the specified request pdu listener from listening for packets on the default request pdu port 161.

The listener will not be removed from all ListeningContext objects that are in the ListeningContextPool. In order to do that, use ListeningContextPool.removeRequestPduListenerFromPool()

Specified by:

removeRequestPduListener in interface SnmpContextBasisFace

Parameters:

l - The request PDU listener

Throws:

IOException

See Also:

• SnmpContextBasisFace.removeRequestPduListener(RequestPduListener, int)
• SnmpContextBasisFace.DEFAULT_PORT

addRequestPduListener

public void addRequestPduListener(RequestPduListener l,
 int port)
                           throws IOException

Description copied from interface: SnmpContextBasisFace

Adds the specified request pdu listener to receive PDUs on the specified port from the host that matches this context.

The ListeningContext class will do the actual listening for PDUs. This context will add itself to a ListeningContextPool object and will only pass the event to its listeners if the pdu matches this context and is a request pdu.

Don't use the TCP_SOCKET when listening for request PDUs. It doesn't provide functionality to send a response back.

Specified by:

addRequestPduListener in interface SnmpContextBasisFace

Parameters:

l - The request PDU listener

port - The port the request PDUs are received on

Throws:

IOException

See Also:

• ListeningContextPool(int, String, String)
• ListeningContextPool.addRawPduListener(RawPduListener)

removeRequestPduListener

public void removeRequestPduListener(RequestPduListener l,
 int port)
                              throws IOException

Description copied from interface: SnmpContextBasisFace

Removes the specified request pdu listener from listening for packets on the specified port.

The listener will not be removed from all ListeningContext objects that are in the ListeningContextPool. In order to do that, use ListeningContextPool.removeRequestPduListenerFromPool()

Specified by:

removeRequestPduListener in interface SnmpContextBasisFace

Parameters:

l - The request PDU listener

port - The port the request PDUs are received on

Throws:

IOException

See Also:

• ListeningContextPool(int, String, String)
• ListeningContextPool.removeRawPduListener(RawPduListener)
• ListeningContextPool.removeRawPduListenerFromPool(RawPduListener)

addRequestPduListener

public void addRequestPduListener(RequestPduListener l,
 ListeningContextPool lcontext)
                           throws IOException

Description copied from interface: SnmpContextBasisFace

Adds the specified request pdu listener to receive PDUs on the specified listening context that matches this context.

The ListeningContext class will do the actual listening for PDUs. This context will add itself to a ListeningContextPool object and will only pass the event to its listeners if the pdu matches this context and is a request pdu.

Don't use the TCP_SOCKET when listening for request PDUs. It doesn't provide functionality to send a response back.

Specified by:

addRequestPduListener in interface SnmpContextBasisFace

Parameters:

l - The request PDU listener

lcontext - The listening context

Throws:

IOException

See Also:

• ListeningContextPool(int, String, String)
• ListeningContextPool.addRawPduListener(RawPduListener)

removeRequestPduListener

public void removeRequestPduListener(RequestPduListener l,
 ListeningContextPool lcontext)
                              throws IOException

Description copied from interface: SnmpContextBasisFace

Removes the specified request pdu listener from listening for packets on the specified listening context.

The listener will not be removed from all ListeningContext objects that are in the ListeningContextPool. In order to do that, use ListeningContextPool.removeRequestPduListenerFromPool()

Specified by:

removeRequestPduListener in interface SnmpContextBasisFace

Parameters:

l - The request PDU listener

lcontext - The listening context

Throws:

IOException

See Also:

• ListeningContextPool(int, String, String)
• ListeningContextPool.removeRawPduListener(RawPduListener)
• ListeningContextPool.removeRawPduListenerFromPool(RawPduListener)

processIncomingPdu

public Pdu processIncomingPdu(byte[] message)
                       throws DecodingException,
IOException

Processes the incoming PDU with the current context.

Specified by:

processIncomingPdu in interface SnmpContextBasisFace

Throws:

DecodingException

IOException

See Also:

• SnmpContext.processIncomingPdu(byte[])

toString

public String toString()

Returns a string representation of the object.

Overrides:

toString in class Object

Returns:

The string

clone

public Object clone()
             throws CloneNotSupportedException

This method is not supported. It will throw a CloneNotSupportedException.

Specified by:

clone in interface SnmpContextBasisFace

Throws:

CloneNotSupportedException - Thrown when the constructor generates an IOException or when in one of the Pool classes.

Since:

4_14