Class CMFChannel

java.lang.Object

java.util.Observable

org.jpos.iso.BaseChannel

org.jpos.iso.channel.CMFChannel

All Implemented Interfaces:

Cloneable, Configurable, ExceptionHandlerAware, BaseChannelMBean, ClientChannel, FactoryChannel, FilteredChannel, ISOChannel, ISOSource, ServerChannel, ISOMsgMetrics.Source, LogSource

public class CMFChannel
extends BaseChannel

ISOChannel implementation for the jPOS-CMF framing. This channel uses a 3-byte big-endian length prefix (24-bit unsigned) and no additional message header.

Keep-alive handling

A zero-length frame is treated as a keep-alive. When a keep-alive is received and either replyKeepAlive is enabled or BaseChannel.isExpectKeepAlive() returns true, the channel echoes the keep-alive back to the peer.

Configuration

• reply-keepalive (boolean, default true): Whether to echo a received keep-alive (zero-length frame) back to the peer.
• max-keepalives-in-a-row (integer, default 0): Maximum number of consecutive keep-alives allowed while waiting for a non-zero length frame. A value of 0 disables the limit (unlimited), preserving legacy behavior.

Since:

3.0.1

See Also:

• ISOMsg
• ISOException
• ISOChannel
• ISOPackager

Field Summary

Fields inherited from class BaseChannel

cnt, header, incomingFilters, logger, originalRealm, outgoingFilters, overrideHeader, packager, realm, serverIn, serverInLock, serverOut, serverOutLock, serverSocket, socketFactory, usable

Fields inherited from interface ISOChannel

CONNECT, RX, SIZEOF_CNT, TX

Constructor Summary

Constructors

Constructor	Description
CMFChannel()	Creates an unconfigured CMFChannel.
CMFChannel(String host, int port, ISOPackager p)	Constructs a client CMFChannel.
CMFChannel(ISOPackager p)	Constructs a server CMFChannel.
CMFChannel(ISOPackager p, ServerSocket serverSocket)	Constructs a server CMFChannel associated with an existing ServerSocket.

Method Summary

Modifier and Type	Method	Description
protected int	getHeaderLength()	Returns the channel header length.
int	getMaxPacketLength()	Returns the maximum packet length supported by this channel.
protected int	getMessageLength()	Reads the CMF message length prefix.
protected void	sendMessageHeader(ISOMsg m, int len)	Sends the message header (no-op).
protected void	sendMessageLength(int len)	Sends the CMF message length prefix.
void	setConfiguration(Configuration cfg)	Applies configuration to this channel.

Methods inherited from class BaseChannel

accept, addFilter, addFilter, addIncomingFilter, addOutgoingFilter, applyIncomingFilters, applyIncomingFilters, applyOutgoingFilters, applyTimeout, clone, closeSocket, connect, connect, createISOMsg, createMsg, disconnect, getBytes, getChannel, getConfiguration, getCounters, getDynamicHeader, getDynamicPackager, getDynamicPackager, getDynamicPackager, getExceptionHandlers, getHeader, getHeaderLength, getHeaderLength, getHost, getIncomingFilters, getISOMsgMetrics, getLogger, getMessage, getMessageTrailer, getMessageTrailler, getName, getOriginalRealm, getOutgoingFilters, getPackager, getPort, getRealm, getServerSocket, getSocket, getSocketFactory, getSoLingerSeconds, getTimeout, incrementMsgInCounter, incrementMsgOutCounter, isConnected, isExpectKeepAlive, isOverrideHeader, isRejected, isSoLingerOn, newSocket, newSocket, pack, postConnectHook, readHeader, receive, reconnect, removeFilter, removeFilter, removeIncomingFilter, removeOutgoingFilter, resetCounters, send, send, sendKeepAlive, sendMessage, sendMessageTrailer, sendMessageTrailler, sendMessageTrailler, setHeader, setHeader, setHost, setHost, setIncomingFilters, setISOMsgMetrics, setLocalAddress, setLogger, setMaxPacketLength, setName, setOutgoingFilters, setOverrideHeader, setPackager, setPort, setServerSocket, setSocketFactory, setSoLinger, setTimeout, setUsable, shouldIgnore, streamReceive, unpack

Methods inherited from class Observable

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

Methods inherited from class Object

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

Methods inherited from interface ExceptionHandlerAware

addHandler, addHandler, handle, removeHandler, removeHandler, removeHandlers

Constructor Details

CMFChannel

public CMFChannel()

Creates an unconfigured CMFChannel. The caller is expected to set the packager/connection parameters through the usual BaseChannel configuration and/or setters before use.

CMFChannel

public CMFChannel(String host,
 int port,
 ISOPackager p)

Constructs a client CMFChannel.

Parameters:

host - server TCP address or hostname.

port - server TCP port number.

p - the ISOPackager used to pack/unpack ISOMsgs.

See Also:

• ISOPackager

CMFChannel

public CMFChannel(ISOPackager p)
           throws IOException

Constructs a server CMFChannel. This constructor creates a ServerSocket internally (as per BaseChannel) and waits for inbound connections when

invalid reference

#accept()

is invoked.

Parameters:

p - the ISOPackager used to pack/unpack ISOMsgs.

Throws:

IOException - if the underlying server socket cannot be created.

See Also:

• ISOPackager

CMFChannel

public CMFChannel(ISOPackager p,
 ServerSocket serverSocket)
           throws IOException

Constructs a server CMFChannel associated with an existing ServerSocket.

Parameters:

p - the ISOPackager used to pack/unpack ISOMsgs.

serverSocket - the server socket used to accept a connection.

Throws:

IOException - if an I/O error occurs while initializing the channel.

See Also:

• ISOPackager

Method Details

sendMessageLength

protected void sendMessageLength(int len)
                          throws IOException

Sends the CMF message length prefix. The CMF framing uses a 3-byte big-endian length prefix (24-bit unsigned).

Overrides:

sendMessageLength in class BaseChannel

Parameters:

len - the packed message length in bytes.

Throws:

IOException - if an I/O error occurs writing to the socket output stream or if len is outside the valid range (0..0xFFFFFF).

getMessageLength

protected int getMessageLength()
                        throws IOException,
ISOException

Reads the CMF message length prefix. Reads a 3-byte big-endian length value. A zero-length frame is treated as a keep-alive. When a keep-alive is received and either replyKeepAlive is enabled or BaseChannel.isExpectKeepAlive() is true, the keep-alive is echoed back to the peer. The method continues reading until a non-zero length is obtained.

If max-keepalives-in-a-row is configured to a value greater than 0, the method will fail after receiving more than that number of consecutive keep-alives without a subsequent non-zero length frame.

Overrides:

getMessageLength in class BaseChannel

Returns:

the packed message length in bytes (always > 0).

Throws:

IOException - if an I/O error occurs reading from the socket input stream, or if too many consecutive keep-alives are received (when limited).

ISOException - if the channel detects an ISO-level framing/processing error.

getHeaderLength

protected int getHeaderLength()

Returns the channel header length. CMF framing does not include a separate message header beyond the 3-byte length prefix.

Overrides:

getHeaderLength in class BaseChannel

Returns:

0.

sendMessageHeader

protected void sendMessageHeader(ISOMsg m,
 int len)

Sends the message header (no-op). CMF framing does not define a message header; only the length prefix is used.

Overrides:

sendMessageHeader in class BaseChannel

Parameters:

m - the message being sent.

len - the packed message length in bytes.

setConfiguration

public void setConfiguration(Configuration cfg)
                      throws ConfigurationException

Applies configuration to this channel. In addition to the base BaseChannel configuration, this method reads:

• reply-keepalive (boolean, default true).
• max-keepalives-in-a-row (integer, default 0).

Specified by:

setConfiguration in interface Configurable

Overrides:

setConfiguration in class BaseChannel

Parameters:

cfg - the configuration source.

Throws:

ConfigurationException - if configuration cannot be applied.

getMaxPacketLength

public int getMaxPacketLength()

Returns the maximum packet length supported by this channel. CMF framing uses a 3-byte unsigned length prefix (24-bit). Therefore, the maximum representable non-zero payload length is 0xFFFFFF (16,777,215 bytes).

Overrides:

getMaxPacketLength in class BaseChannel

Returns:

the maximum packet length, in bytes.