org.snmp4j.transport

Class DefaultTcpTransportMapping

java.lang.Object

org.snmp4j.transport.AbstractTransportMapping<TcpAddress>

org.snmp4j.transport.TcpTransportMapping

org.snmp4j.transport.DefaultTcpTransportMapping

All Implemented Interfaces:

ConnectionOrientedTransportMapping<TcpAddress>, TransportMapping<TcpAddress>

public class DefaultTcpTransportMapping
extends TcpTransportMapping

The DefaultTcpTransportMapping implements a TCP transport mapping with the Java 1.4 new IO API. It uses a single thread for processing incoming and outgoing messages. The thread is started when the listen method is called, or when an outgoing request is sent using the sendMessage method.

Version:

2.8.5

Author:

Frank Fock

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected class	DefaultTcpTransportMapping.ServerThread
static class	DefaultTcpTransportMapping.SnmpMesssageLengthDecoder

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_MAX_BUSY_LOOPS The maximum number of loops trying to read data from an incoming port but no data has been received.
protected MessageLengthDecoder	messageLengthDecoder
protected WorkerTask	server
protected DefaultTcpTransportMapping.ServerThread	serverThread
protected CommonTimer	socketCleaner
protected Map<Address,org.snmp4j.transport.DefaultTcpTransportMapping.SocketEntry>	sockets

Fields inherited from class org.snmp4j.transport.TcpTransportMapping

openSocketOnSending, suspendedAddresses, tcpAddress

Fields inherited from class org.snmp4j.transport.AbstractTransportMapping

asyncMsgProcessingSupported, maxInboundMessageSize, transportListener

Constructor Summary

Constructors

Constructor and Description
DefaultTcpTransportMapping() Creates a default TCP transport mapping with the server for incoming messages disabled.
DefaultTcpTransportMapping(TcpAddress serverAddress) Creates a default TCP transport mapping that binds to the given address (interface) on the local host.

Method Summary

Modifier and Type	Method and Description
protected void	addBufferToReadBuffer(org.snmp4j.transport.DefaultTcpTransportMapping.SocketEntry entry, ByteBuffer byteBuffer)
void	close() Closes all open sockets and stops the internal server thread that processes messages and removes all queued requests and socket entries.
boolean	close(TcpAddress remoteAddress) Closes a connection to the supplied remote address, if it is open.
long	getConnectionTimeout() Gets the connection timeout.
TcpAddress	getListenAddress() Returns the address that represents the actual incoming address this transport mapping uses to listen for incoming packets.
protected int	getMaxBusyLoops()
int	getMaxInboundMessageSize() Gets the inbound buffer size for incoming requests.
MessageLengthDecoder	getMessageLengthDecoder() Returns the MessageLengthDecoder used by this transport mapping.
int	getPriority() Returns the priority of the internal listen thread.
String	getThreadName() Returns the name of the listen thread.
boolean	isListening() Returns true if the transport mapping is listening for incoming messages.
boolean	isServerEnabled() Checks whether a server for incoming requests is enabled.
void	listen() Listen for incoming and outgoing requests.
protected Object	removeSocketEntry(TcpAddress incomingAddress)
void	sendMessage(TcpAddress address, byte[] message, TransportStateReference tmStateReference) Sends a SNMP message to the supplied address.
void	setConnectionTimeout(long connectionTimeout) Sets the connection timeout.
protected void	setMaxBusyLoops(int maxBusyLoops)
void	setMaxInboundMessageSize(int maxInboundMessageSize) Sets the maximum buffer size for incoming requests.
void	setMessageLengthDecoder(MessageLengthDecoder messageLengthDecoder) Sets the message length decoder.
void	setPriority(int newPriority) Changes the priority of the server thread for this TCP transport mapping.
void	setServerEnabled(boolean serverEnabled) Sets whether a server for incoming requests should be created when the transport is set into listen state.
protected void	setSocketOptions(ServerSocket serverSocket) Sets optional server socket options.
void	setThreadName(String name) Sets the name of the listen thread for this UDP transport mapping.
protected void	socketClosedRemotely(SelectionKey sk, SocketChannel readChannel, TcpAddress incomingAddress)

Methods inherited from class org.snmp4j.transport.TcpTransportMapping

addTransportStateListener, fireConnectionStateChanged, getAddress, getSupportedAddressClass, handleDroppedMessageToSend, isOpenSocketOnSending, removeTransportStateListener, resumeAddress, setOpenSocketOnSending, suspendAddress

Methods inherited from class org.snmp4j.transport.AbstractTransportMapping

addTransportListener, fireProcessMessage, isAsyncMsgProcessingSupported, removeTransportListener, setAsyncMsgProcessingSupported

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.snmp4j.TransportMapping

addTransportListener, removeTransportListener

Field Detail

DEFAULT_MAX_BUSY_LOOPS

public static final int DEFAULT_MAX_BUSY_LOOPS

The maximum number of loops trying to read data from an incoming port but no data has been received. A value of 0 or less disables the check.

See Also:

Constant Field Values

sockets

protected Map<Address,org.snmp4j.transport.DefaultTcpTransportMapping.SocketEntry> sockets

server

protected WorkerTask server

serverThread

protected DefaultTcpTransportMapping.ServerThread serverThread

socketCleaner

protected CommonTimer socketCleaner

messageLengthDecoder

protected MessageLengthDecoder messageLengthDecoder

Constructor Detail

DefaultTcpTransportMapping

public DefaultTcpTransportMapping()
                           throws IOException

Creates a default TCP transport mapping with the server for incoming messages disabled.

Throws:

IOException - on failure of binding a local port.

DefaultTcpTransportMapping

public DefaultTcpTransportMapping(TcpAddress serverAddress)
                           throws IOException

Creates a default TCP transport mapping that binds to the given address (interface) on the local host.

Parameters:

serverAddress - the TcpAddress instance that describes the server address to listen on incoming connection requests.

Throws:

IOException - if the given address cannot be bound.

Method Detail

listen

public void listen()
            throws IOException

Listen for incoming and outgoing requests. If the serverEnabled member is false the server for incoming requests is not started. This starts the internal server thread that processes messages.

Specified by:

listen in interface TransportMapping<TcpAddress>

Specified by:

listen in class TcpTransportMapping

Throws:

SocketException - when the transport is already listening for incoming/outgoing messages.

IOException - if the listen port could not be bound to the server thread.

setPriority

public void setPriority(int newPriority)

Changes the priority of the server thread for this TCP transport mapping. This method has no effect, if called before listen() has been called for this transport mapping or if SNMP4J is configured to use a non-default thread factory.

Parameters:

newPriority - the new priority.

Since:

1.2.2

See Also:

Thread.setPriority(int)

getPriority

public int getPriority()

Returns the priority of the internal listen thread.

Returns:

a value between Thread.MIN_PRIORITY and Thread.MAX_PRIORITY.

Since:

1.2.2

setThreadName

public void setThreadName(String name)

Sets the name of the listen thread for this UDP transport mapping. This method has no effect, if called before listen() has been called for this transport mapping.

Parameters:

name - the new thread name.

Since:

1.6

getThreadName

public String getThreadName()

Returns the name of the listen thread.

Returns:

the thread name if in listening mode, otherwise null.

Since:

1.6

close

public void close()

Closes all open sockets and stops the internal server thread that processes messages and removes all queued requests and socket entries.

Specified by:

close in interface TransportMapping<TcpAddress>

Specified by:

close in class TcpTransportMapping

close

public boolean close(TcpAddress remoteAddress)
              throws IOException

Closes a connection to the supplied remote address, if it is open. This method is particularly useful when not using a timeout for remote connections.

Parameters:

remoteAddress - the address of the peer socket.

Returns:

true if the connection has been closed and false if there was nothing to close.

Throws:

IOException - if the remote address cannot be closed due to an IO exception.

Since:

1.7.1

sendMessage

public void sendMessage(TcpAddress address,
                        byte[] message,
                        TransportStateReference tmStateReference)
                 throws IOException

Sends a SNMP message to the supplied address.

Specified by:

sendMessage in interface TransportMapping<TcpAddress>

Specified by:

sendMessage in class TcpTransportMapping

Parameters:

address - an TcpAddress. A ClassCastException is thrown if address is not a TcpAddress instance.

message - byte[] the message to sent.

tmStateReference - the (optional) transport model state reference as defined by RFC 5590 section 6.1.

Throws:

IOException - if an IO exception occurs while trying to send the message.

getConnectionTimeout

public long getConnectionTimeout()

Gets the connection timeout. This timeout specifies the time a connection may be idle before it is closed.

Returns:

long the idle timeout in milliseconds.

setConnectionTimeout

public void setConnectionTimeout(long connectionTimeout)

Sets the connection timeout. This timeout specifies the time a connection may be idle before it is closed.

Specified by:

setConnectionTimeout in interface ConnectionOrientedTransportMapping<TcpAddress>

Specified by:

setConnectionTimeout in class TcpTransportMapping

Parameters:

connectionTimeout - the idle timeout in milliseconds. A zero or negative value will disable any timeout and connections opened by this transport mapping will stay opened until they are explicitly closed.

isServerEnabled

public boolean isServerEnabled()

Checks whether a server for incoming requests is enabled.

Returns:

boolean

getMessageLengthDecoder

public MessageLengthDecoder getMessageLengthDecoder()

Description copied from class: TcpTransportMapping

Returns the MessageLengthDecoder used by this transport mapping.

Specified by:

getMessageLengthDecoder in interface ConnectionOrientedTransportMapping<TcpAddress>

Specified by:

getMessageLengthDecoder in class TcpTransportMapping

Returns:

a MessageLengthDecoder instance.

setServerEnabled

public void setServerEnabled(boolean serverEnabled)

Sets whether a server for incoming requests should be created when the transport is set into listen state. Setting this value has no effect until the listen() method is called (if the transport is already listening, close() has to be called before).

Parameters:

serverEnabled - if true if the transport will listens for incoming requests after listen() has been called.

setMessageLengthDecoder

public void setMessageLengthDecoder(MessageLengthDecoder messageLengthDecoder)

Sets the message length decoder. Default message length decoder is the DefaultTcpTransportMapping.SnmpMesssageLengthDecoder. The message length decoder must be able to decode the total length of a message for this transport mapping protocol(s).

Specified by:

setMessageLengthDecoder in interface ConnectionOrientedTransportMapping<TcpAddress>

Specified by:

setMessageLengthDecoder in class TcpTransportMapping

Parameters:

messageLengthDecoder - a MessageLengthDecoder instance.

getMaxInboundMessageSize

public int getMaxInboundMessageSize()

Gets the inbound buffer size for incoming requests. When SNMP packets are received that are longer than this maximum size, the messages will be silently dropped and the connection will be closed.

Specified by:

getMaxInboundMessageSize in interface TransportMapping<TcpAddress>

Overrides:

getMaxInboundMessageSize in class AbstractTransportMapping<TcpAddress>

Returns:

the maximum inbound buffer size in bytes.

setMaxInboundMessageSize

public void setMaxInboundMessageSize(int maxInboundMessageSize)

Sets the maximum buffer size for incoming requests. When SNMP packets are received that are longer than this maximum size, the messages will be silently dropped and the connection will be closed.

Parameters:

maxInboundMessageSize - the length of the inbound buffer in bytes.

isListening

public boolean isListening()

Description copied from interface: TransportMapping

Returns true if the transport mapping is listening for incoming messages. For connection oriented transport mappings this is a prerequisite to be able to send SNMP messages. For connectionless transport mappings it is a prerequisite to be able to receive responses.

Returns:

true if this transport mapping is listening for messages.

getMaxBusyLoops

protected int getMaxBusyLoops()

setMaxBusyLoops

protected void setMaxBusyLoops(int maxBusyLoops)

setSocketOptions

protected void setSocketOptions(ServerSocket serverSocket)

Sets optional server socket options. The default implementation does nothing.

Parameters:

serverSocket - the ServerSocket to apply additional non-default options.

getListenAddress

public TcpAddress getListenAddress()

Description copied from interface: TransportMapping

Returns the address that represents the actual incoming address this transport mapping uses to listen for incoming packets.

Specified by:

getListenAddress in interface TransportMapping<TcpAddress>

Overrides:

getListenAddress in class TcpTransportMapping

Returns:

the address for incoming packets or null this transport mapping is not configured to listen for incoming packets.

addBufferToReadBuffer

protected void addBufferToReadBuffer(org.snmp4j.transport.DefaultTcpTransportMapping.SocketEntry entry,
                                     ByteBuffer byteBuffer)

socketClosedRemotely

protected void socketClosedRemotely(SelectionKey sk,
                                    SocketChannel readChannel,
                                    TcpAddress incomingAddress)
                             throws IOException

Throws:

IOException

removeSocketEntry

protected Object removeSocketEntry(TcpAddress incomingAddress)