org.jscsi.target.settings

Class ConnectionSettingsNegotiator

java.lang.Object

org.jscsi.target.settings.SettingsNegotiator

org.jscsi.target.settings.ConnectionSettingsNegotiator

public final class ConnectionSettingsNegotiator
extends SettingsNegotiator

In addition to offering all methods of their SettingsNegotiator parent class, ConnectionSettingsNegotiator instances provide all methods necessary for text parameter negotiation and for creating Settings objects, which allow access to the current parameters.

Each instance of this class belongs to one TargetConnection, for which it manages all connection-specific parameters. A similar association exists between the connection's enclosing TargetSession and the sessionSettingsNegotiator member variable.

A negotiation sequence consists of the following steps, performed in the given order:

1. Call beginNegotiation() until it returns true.
2. One or, if the initiator is using multiple PDU sequences, multiple calls of negotiate(TargetServer, LoginStage, boolean, boolean, List, List). The method will return false if there was a problem.
3. Call checkConstraints() to check more complex requirements. The method will return false if there was a problem.
4. Call finishNegotiation(boolean) with the appropriate parameter. This step is mandatory.

Author:

Andreas Ergenzinger, University of Konstanz

Field Summary

Fields inherited from class org.jscsi.target.settings.SettingsNegotiator

backUpEntries, entries

Constructor Summary

Constructors

Constructor and Description
ConnectionSettingsNegotiator(SessionSettingsNegotiator sessionSettingsNegotiator) The ConnectionSettingsNegotiator constructor.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	beginNegotiation() This method must be called at the beginning of a parameter negotiation sequence.
boolean	checkConstraints() Checks constraints that cannot be checked at the Entry level, e.g.
void	finishNegotiation(boolean commitChanges) This method must be called at the end of a negotiation sequence.
Settings	getSettings() This method checks if any parameter changes have been committed since the last call and, if so, creates a new Settings object reflecting the current parameters.
protected void	initializeEntries() Adds a properly initialized Entry object to SettingsNegotiator.entries for every parameter managed by this SettingsNegotiator.
boolean	negotiate(TargetServer target, LoginStage loginStage, boolean leadingConnection, boolean initialPdu, List<String> requestKeyValuePairs, List<String> responseKeyValuePairs) Processes one or more key-value pairs sent by the initiator, formulates response key-value pairs and changes the involved Entry instances accordingly.
protected void	updateSettingsBuilderComponent() Updates ConnectionSettingsBuilderComponent with the currently valid parameters retrieved from the elements of SettingsNegotiator.entries.

Methods inherited from class org.jscsi.target.settings.SettingsNegotiator

backUpEntries, commitOrRollBackChanges, copy

Methods inherited from class java.lang.Object

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

Constructor Detail

ConnectionSettingsNegotiator

public ConnectionSettingsNegotiator(SessionSettingsNegotiator sessionSettingsNegotiator)

The ConnectionSettingsNegotiator constructor.

Parameters:

sessionSettingsNegotiator - the SessionSettingsNegotiator maintaining all Entry objects for session-wide parameters

Method Detail

beginNegotiation

public boolean beginNegotiation()

This method must be called at the beginning of a parameter negotiation sequence.

This method will block until no other ConnectionSettingsNegotiator is negotiating and will return true if negotiations may proceed, or false, if the request for the permission to negotiate was denied.

Returns:

true if and only if the caller is allowed to negotiate parameters

See Also:

finishNegotiation(boolean)

finishNegotiation

public void finishNegotiation(boolean commitChanges)

This method must be called at the end of a negotiation sequence. If there was a problem during negotiations, all changes to the managed Entry objects must be discarded by setting the commitChanges parameter to false. If it is true, then the parameter changes will be incorporated into the updated settings.

Calling this method should be ensured by a try ... catch ... finally block.

Parameters:

commitChanges - true if and only if the negotiated parameter changes are to be committed

negotiate

public boolean negotiate(TargetServer target,
                LoginStage loginStage,
                boolean leadingConnection,
                boolean initialPdu,
                List<String> requestKeyValuePairs,
                List<String> responseKeyValuePairs)

Processes one or more key-value pairs sent by the initiator, formulates response key-value pairs and changes the involved Entry instances accordingly.

Parameters:

loginStage - specifies the current stage or phase

leadingConnection - true if and only if the connection is the first connection of the enclosing session

initialPdu - true if and only if the key-value pairs were sent in the first ProtocolDataUnit received on this connection

requestKeyValuePairs - contains the key-value pairs from the initiator; processed elements will be removed

responseKeyValuePairs - will contain the key-value pairs from the jSCSI target

Returns:

true if everything went fine and false if there was an irreconcilable problem

checkConstraints

public boolean checkConstraints()

Description copied from class: SettingsNegotiator

Checks constraints that cannot be checked at the Entry level, e.g. because they depend on the values of multiple parameters.

Specified by:

checkConstraints in class SettingsNegotiator

Returns:

true if everything is fine, false if that is not the case

getSettings

public Settings getSettings()

This method checks if any parameter changes have been committed since the last call and, if so, creates a new Settings object reflecting the current parameters.

Returns:

The current parameters

initializeEntries

protected void initializeEntries()

Description copied from class: SettingsNegotiator

Adds a properly initialized Entry object to SettingsNegotiator.entries for every parameter managed by this SettingsNegotiator.

Specified by:

initializeEntries in class SettingsNegotiator

updateSettingsBuilderComponent

protected void updateSettingsBuilderComponent()

Updates ConnectionSettingsBuilderComponent with the currently valid parameters retrieved from the elements of SettingsNegotiator.entries.