org.jscsi.initiator.connection

Class Session

java.lang.Object

org.jscsi.initiator.connection.Session

public final class Session
extends Object

Session

A session or Initiator Target Nexus is a directed communication from an iSCSI Initiator to an iSCSI Target. Each session can contain several connections. This allows a better usage of bandwidth and decreases latency times. The Abstract Class is used to implement serveral single- and multithreaded variants of Sessions

Author:

Volker Wildi, University of Konstanz, Patrice Matthias Brend'amour, University of Kontanz, Sebastian Graf, University of Kontanz

Field Summary

Fields

Modifier and Type	Field and Description
protected TargetCapacityInformations	capacityInformations This instance contains the informations about the capacity of the connected target.
protected org.jscsi.utils.SerialArithmeticNumber	commandSequenceNumber The Command Sequence Number of this session.
protected Configuration	configuration The Configuration instance for this session.
protected LinkedBlockingQueue<Connection>	connections A List object with all open connections.
protected LinkFactory	factory The LinkFactory instance for this session.
protected InetSocketAddress	inetSocketAddress The unique name of the connected iSCSI Target.
protected org.jscsi.utils.SerialArithmeticNumber	initiatorTaskTag The initiator uses this Initiator Task Tag to relate data to the appropriate command.
protected org.jscsi.utils.SerialArithmeticNumber	maximumCommandSequenceNumber The Maximum Command Sequence Number of this session.
protected short	nextFreeConnectionID The index of the next used connection ID.
protected IPhase	phase The session is in this phase.
protected String	targetName The unique name of the connected iSCSI Target.
protected short	targetSessionIdentifyingHandle The Target Session Identifying Handle.
protected AbstractTaskBalancer	taskBalancer Handles the load balancing of the task distribution to the opened connections.
protected boolean	tsihChanged Flag to indicate, if the login phase of this session is successfully completed.

Constructor Summary

Constructors

Constructor and Description
Session(LinkFactory linkFactory, Configuration initConfiguration, String initTargetName, InetSocketAddress inetAddress, ExecutorService initExecutor) Constructor to create a new, empty AbsSession object with a maximum number of allowed connections to a given iSCSI Target.

Method Summary

Methods

Modifier and Type	Method and Description
void	addConnections(int max) Adds a number of new connections to this session.
protected short	addNewConnection() Adds a new connection to this session with the next free connection ID (if the maximum number is not reached).
void	addOutstandingTask(Connection connection, ITask task) Adds a Task to the outstandingTasks Hashmap.
void	close() Closes this session instances with all opened connections.
void	finishedTask(ITask ftask) removes Task from outstandingTasks.
long	getBlockSize() Returns the used block size of the connected iSCSI Target.
long	getCapacity() Returns the capacity (in blocks) of the connected iSCSI Target.
int	getCommandSequenceNumber() Returns the Command Sequence Number of this session.
int	getInitiatorTaskTag() Returns the Initiator Task Tag of this session.
org.jscsi.utils.SerialArithmeticNumber	getMaximumCommandSequenceNumber() Returns the Maximum Command Sequence Number of this session.
Connection	getNextFreeConnection() Returns the next free Connection object of this Session object.
org.jscsi.parser.login.LoginStage	getPhase() Returns the current LoginStage object.
String	getTargetName() Returns the name of the iSCSI Target of this session.
short	getTargetSessionIdentifyingHandle() Returns the Target Session Identifying Handle (TSID) of this Session object.
boolean	hasTargetMoreResources() Has the iSCSI Target enough resources to accept more incoming PDU?
void	incrementCommandSequenceNumber() Increments the Command Sequence Number as defined in RFC1982, where SERIAL_BITS = 32.
void	incrementInitiatorTaskTag() Increments the Initiator Task Tag as defined in RFC1982 where SERIAL_BITS = 32.
void	login() This method invokes the same called method of the current IPhase instance.
void	logout() This method invokes the same called method of the current IPhase instance.
Future<Void>	read(ByteBuffer dst, int logicalBlockAddress, long transferLength) This method invokes the same called method of the current IPhase instance.
void	releaseUsedConnection(Connection connection) Adds a Task to the outstandingTasks Hashmap.
void	restartTask(ITask task) restarts a Task from outstandingTasks.
void	setMaximumCommandSequenceNumber(int newMaximumCommandSequenceNumber) Sets the Maximum Command Sequence Number to a new value.
void	setPhase(IPhase newPhase) This method sets the current IPhase instance to the given value.
void	setTargetSessionIdentifyingHandle(short tsih) Sets the Target Session Identifying Handle (TSIH) to the given value.
void	updateMaxConnections(int max) Updates the MaxConnection setting, so that it grows/shrinks the Connectionlist.
Future<Void>	write(ByteBuffer src, int logicalBlockAddress, long transferLength) This method invokes the same called method of the current IPhase instance.

Methods inherited from class java.lang.Object

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

Field Detail

targetName

protected final String targetName

The unique name of the connected iSCSI Target.

inetSocketAddress

protected final InetSocketAddress inetSocketAddress

The unique name of the connected iSCSI Target.

nextFreeConnectionID

protected short nextFreeConnectionID

The index of the next used connection ID.

phase

protected IPhase phase

The session is in this phase.

capacityInformations

protected final TargetCapacityInformations capacityInformations

This instance contains the informations about the capacity of the connected target.

connections

protected final LinkedBlockingQueue<Connection> connections

A List object with all open connections.

commandSequenceNumber

protected final org.jscsi.utils.SerialArithmeticNumber commandSequenceNumber

The Command Sequence Number of this session.

maximumCommandSequenceNumber

protected final org.jscsi.utils.SerialArithmeticNumber maximumCommandSequenceNumber

The Maximum Command Sequence Number of this session.

initiatorTaskTag

protected final org.jscsi.utils.SerialArithmeticNumber initiatorTaskTag

The initiator uses this Initiator Task Tag to relate data to the appropriate command. And the target uses this tag to correlate the data to the appropriate command that it received earlier.

tsihChanged

protected boolean tsihChanged

Flag to indicate, if the login phase of this session is successfully completed. This flag is also used for the protection of a reseting of targetSessionIdentifyingHandle.

targetSessionIdentifyingHandle

protected short targetSessionIdentifyingHandle

The Target Session Identifying Handle.

configuration

protected final Configuration configuration

The Configuration instance for this session.

factory

protected final LinkFactory factory

The LinkFactory instance for this session.

taskBalancer

protected final AbstractTaskBalancer taskBalancer

Handles the load balancing of the task distribution to the opened connections.

Constructor Detail

Session

public Session(LinkFactory linkFactory,
       Configuration initConfiguration,
       String initTargetName,
       InetSocketAddress inetAddress,
       ExecutorService initExecutor)
        throws Exception

Constructor to create a new, empty AbsSession object with a maximum number of allowed connections to a given iSCSI Target. This is the abstract definition for Session implementations

Parameters:

linkFactory - The LinkFactory which called the Constructor

initConfiguration - The configuration to use within this session.

initTargetName - The name of the iSCSI Target.

inetAddress - The InetSocketAddress of the leading connection of this session.

initExecutor - The ExecutorService for the Connection Threads

Throws:

Exception - if anything happens

Method Detail

getTargetSessionIdentifyingHandle

public final short getTargetSessionIdentifyingHandle()

Returns the Target Session Identifying Handle (TSID) of this Session object.

Returns:

The current Target Session Identifying Handle (TSIH)

setTargetSessionIdentifyingHandle

public final void setTargetSessionIdentifyingHandle(short tsih)

Sets the Target Session Identifying Handle (TSIH) to the given value. This TSIH is specified at the Login Phase by the target in a new session. So, it can only set one time.

Parameters:

tsih - The new Target Session Identifying Handle.

getCommandSequenceNumber

public final int getCommandSequenceNumber()

Returns the Command Sequence Number of this session.

Returns:

The current Command Sequence Number.

setMaximumCommandSequenceNumber

public final void setMaximumCommandSequenceNumber(int newMaximumCommandSequenceNumber)

Sets the Maximum Command Sequence Number to a new value.

Parameters:

newMaximumCommandSequenceNumber - The new Maximum Command Sequence Number.

getMaximumCommandSequenceNumber

public final org.jscsi.utils.SerialArithmeticNumber getMaximumCommandSequenceNumber()

Returns the Maximum Command Sequence Number of this session.

Returns:

The current Maximum Command Sequence Number.

getInitiatorTaskTag

public final int getInitiatorTaskTag()

Returns the Initiator Task Tag of this session.

Returns:

The Initiator Task Tag.

incrementInitiatorTaskTag

public final void incrementInitiatorTaskTag()

Increments the Initiator Task Tag as defined in RFC1982 where SERIAL_BITS = 32.

hasTargetMoreResources

public final boolean hasTargetMoreResources()

Has the iSCSI Target enough resources to accept more incoming PDU?

Returns:

true, if the iSCSI Target has enough resources to accept more incoming PDUs. Else false and hold out for sending.

getTargetName

public final String getTargetName()

Returns the name of the iSCSI Target of this session.

Returns:

The name of the iSCSI Target.

addConnections

public final void addConnections(int max)
                          throws Exception

Adds a number of new connections to this session.

Parameters:

max - The number of Connections to open.

Throws:

Exception - if any error occurs.

addNewConnection

protected final short addNewConnection()
                                throws Exception

Adds a new connection to this session with the next free connection ID (if the maximum number is not reached).

Returns:

The connection ID of the newly created connection.

Throws:

Exception - if any error occurs.

updateMaxConnections

public void updateMaxConnections(int max)

Updates the MaxConnection setting, so that it grows/shrinks the Connectionlist.

Parameters:

max - The maximum number of concurrent Connections to a target.

getNextFreeConnection

public final Connection getNextFreeConnection()
                                       throws org.jscsi.exception.NoSuchConnectionException

Returns the next free Connection object of this Session object.

Returns:

The connection to use for the next task.

Throws:

org.jscsi.exception.NoSuchConnectionException - If there is no such connection.

incrementCommandSequenceNumber

public final void incrementCommandSequenceNumber()

Increments the Command Sequence Number as defined in RFC1982, where SERIAL_BITS = 32.

close

public final void close()
                 throws IOException

Closes this session instances with all opened connections.

Throws:

IOException - if an I/O error occurs.

getBlockSize

public final long getBlockSize()

Returns the used block size of the connected iSCSI Target.

Returns:

The used block size in bytes.

getCapacity

public final long getCapacity()

Returns the capacity (in blocks) of the connected iSCSI Target.

Returns:

The capacity in blocks.

login

public final void login()
                 throws Exception

This method invokes the same called method of the current IPhase instance.

Throws:

Exception - if any error occurs.

logout

public final void logout()
                  throws org.jscsi.exception.TaskExecutionException

This method invokes the same called method of the current IPhase instance.

Throws:

org.jscsi.exception.TaskExecutionException - if any error occurs.

read

public final Future<Void> read(ByteBuffer dst,
                int logicalBlockAddress,
                long transferLength)
                        throws org.jscsi.exception.TaskExecutionException

This method invokes the same called method of the current IPhase instance.

Parameters:

dst - Store the read bytes to this buffer.

logicalBlockAddress - The logical block address of the device to begin the read operation.

transferLength - The number of bytes to read from the device.

Returns:

The Future object.

Throws:

Exception - if any error occurs.

org.jscsi.exception.TaskExecutionException - if execution fails

write

public final Future<Void> write(ByteBuffer src,
                 int logicalBlockAddress,
                 long transferLength)
                         throws org.jscsi.exception.TaskExecutionException

This method invokes the same called method of the current IPhase instance.

Parameters:

src - Write the remaining bytes to the device.

logicalBlockAddress - The logical block address of the device to begin the write operation.

transferLength - The number of bytes to write to the device.

Returns:

The Future object.

Throws:

Exception - if any error occurs.

org.jscsi.exception.TaskExecutionException - if execution fails

getPhase

public final org.jscsi.parser.login.LoginStage getPhase()

Returns the current LoginStage object.

Returns:

The instance to the current LoginStage.

setPhase

public final void setPhase(IPhase newPhase)

This method sets the current IPhase instance to the given value.

Parameters:

newPhase - The new instance to switch to.

finishedTask

public final void finishedTask(ITask ftask)

removes Task from outstandingTasks.

Parameters:

ftask - The Task which was finished .

restartTask

public final void restartTask(ITask task)
                       throws ExecutionException

restarts a Task from outstandingTasks.

Parameters:

task - The failed Task.

Throws:

ExecutionException - for failed restart of the task

addOutstandingTask

public final void addOutstandingTask(Connection connection,
                      ITask task)

Adds a Task to the outstandingTasks Hashmap.

Parameters:

connection - The Connection where the Task will be started

task - The Task which was started.

releaseUsedConnection

public final void releaseUsedConnection(Connection connection)
                                 throws org.jscsi.exception.NoSuchConnectionException

Adds a Task to the outstandingTasks Hashmap.

Parameters:

connection - The Connection which will be released

Throws:

org.jscsi.exception.NoSuchConnectionException - if any errors occur