Package edu.caltech.nanodb.server

Class SessionState

java.lang.Object

edu.caltech.nanodb.server.SessionState

public class SessionState
extends java.lang.Object

This class holds all session state associated with a particular client accessing the database. This object can be stored in thread-local storage to ensure that it can be accessed throughout the database engine to determine current client settings.

Field Summary

Fields

Modifier and Type	Field	Description
private CommandState	cmdState	The command state of this session.
private static java.util.concurrent.atomic.AtomicInteger	nextSessionID	This static variable holds the next session ID to assign to a client session.
private java.io.PrintStream	outputStream	This is the output stream for the current client.
private int	sessionID	The unique session ID assigned to this client session.
private static java.lang.ThreadLocal<SessionState>	threadLocalState
private TransactionState	txnState	The transaction state of this session.

Constructor Summary

Constructors

Modifier	Constructor	Description
private	SessionState(int sessionID)

Method Summary

Modifier and Type	Method	Description
static SessionState	get()	Returns the current session state, possibly initializing a new session with its own unique ID in the process.
CommandState	getCommandState()
java.io.PrintStream	getOutputStream()
int	getSessionID()	Returns the unique session ID for this client.
TransactionState	getTransactionState()
int	hashCode()
static void	remove()	Removes the session-state from the thread's thread-local storage.
void	setOutputStream(java.io.PrintStream out)

Methods inherited from class java.lang.Object

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

Field Detail

nextSessionID

private static java.util.concurrent.atomic.AtomicInteger nextSessionID

This static variable holds the next session ID to assign to a client session. It must be accessed in a synchronized manner.

threadLocalState

private static java.lang.ThreadLocal<SessionState> threadLocalState

sessionID

private int sessionID

The unique session ID assigned to this client session.

outputStream

private java.io.PrintStream outputStream

This is the output stream for the current client. If there are multiple clients, writing to this stream will go to the client associated with this session.

txnState

private TransactionState txnState

The transaction state of this session.

cmdState

private CommandState cmdState

The command state of this session.

Constructor Detail

SessionState

private SessionState(int sessionID)

Method Detail

get

public static SessionState get()

Returns the current session state, possibly initializing a new session with its own unique ID in the process. This value is stored in thread-local storage, so no thread-safety is required when manipulating the returned object.

Returns:

the session-state for this local thread.

remove

public static void remove()

Removes the session-state from the thread's thread-local storage.

getSessionID

public int getSessionID()

Returns the unique session ID for this client.

Returns:

the unique session ID for this client.

getOutputStream

public java.io.PrintStream getOutputStream()

setOutputStream

public void setOutputStream(java.io.PrintStream out)

getTransactionState

public TransactionState getTransactionState()

getCommandState

public CommandState getCommandState()

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object