databaseHandler

Class DatabaseHandler

java.lang.Object

databaseHandler.DatabaseHandler

All Implemented Interfaces:

java.lang.Runnable

public class DatabaseHandler
extends java.lang.Object
implements java.lang.Runnable

The class DatabaseHandler is responsible for:
- creating database for closed flows
- storing closed flows to the database
- closing the database and reopening a new one when the database achieve a certain size

It is intended to run in its own thread. The used database is SQLite: http://www.sqlite.org/

Author:

Tomasz Bujlow (tbu@es.aau.dk)

Field Summary

Fields

Modifier and Type	Field and Description
private java.lang.String	clientId Identifier of the VBS client.
private java.lang.String	databaseFolderPath Path to the folder where the database is stored.
private java.lang.Thread	databaseHandlerThread Thread used by the class.
private java.lang.String	databasePath Path to the current database file.
(package private) SQLiteDB	db The database object.
private java.lang.String	globalIP Global IP of the VBS client.
private boolean	isStarted Used to dermine if the thread is already started.
private static org.apache.log4j.Logger	log Used to log different events.
private ClosedFlowsQueue	myClosedFlowsQueue Queue of closed flows.
private PerformanceMonitorQueue	myPerformanceMonitorQueue Queue of performance measurements.
private java.lang.String	networkName Name of the network in which the VBS client is located.
private boolean	runFlag The thread will stop when this flag is false.
private int	samplingInterval Tells how often the database maintenance tasks are done.

Constructor Summary

Constructors

Constructor and Description
DatabaseHandler(ClosedFlowsQueue closedFlowsQueue, PerformanceMonitorQueue performanceMonitorQueue, java.lang.String databaseFolderPath) Constructs the object.

Method Summary

Methods

Modifier and Type	Method and Description
void	emptyStorage() Moves all the closed flows from the closed flows storage to the database.
private static java.lang.String	getSystemInfo() Gets system information.
boolean	isAlive() Checks if DatabaseHandler is alive.
private void	maintenance() Does the periodical maintenance.
void	run() Runs the thread.
void	setClientId(java.lang.String clientId) Sets the client identifier.
private void	setDatabase() Sets the database.
void	setGlobalIP(java.lang.String globalIP) Sets the global IP address of the client.
void	setNetworkName(java.lang.String networkName) Sets the network name.
void	setSamplingInterval(int samplingInterval) Sets the frequency of database maintenance.
void	start() Starts the thread.
void	stop() Stops the thread.

Methods inherited from class java.lang.Object

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

Field Detail

log

private static org.apache.log4j.Logger log

Used to log different events.

databaseHandlerThread

private java.lang.Thread databaseHandlerThread

Thread used by the class.

runFlag

private boolean runFlag

The thread will stop when this flag is false.

isStarted

private boolean isStarted

Used to dermine if the thread is already started.

samplingInterval

private int samplingInterval

Tells how often the database maintenance tasks are done.

clientId

private java.lang.String clientId

Identifier of the VBS client. It will be included in every database to mark to which client it belongs.

globalIP

private java.lang.String globalIP

Global IP of the VBS client. It will be included in every database file.

networkName

private java.lang.String networkName

Name of the network in which the VBS client is located. It will be included in every database file.

databaseFolderPath

private java.lang.String databaseFolderPath

Path to the folder where the database is stored.

databasePath

private java.lang.String databasePath

Path to the current database file.

db

SQLiteDB db

The database object.

myClosedFlowsQueue

private ClosedFlowsQueue myClosedFlowsQueue

Queue of closed flows. They can be stored to the database.

myPerformanceMonitorQueue

private PerformanceMonitorQueue myPerformanceMonitorQueue

Queue of performance measurements. They can be stored to the database.

Constructor Detail

DatabaseHandler

public DatabaseHandler(ClosedFlowsQueue closedFlowsQueue,
               PerformanceMonitorQueue performanceMonitorQueue,
               java.lang.String databaseFolderPath)

Constructs the object.

Parameters:

closedFlowsQueue - queue of closed flows

performanceMonitorQueue - queue of performance measurements

databaseFolderPath - path to a folder containing the database

Method Detail

start

public void start()

Starts the thread.

stop

public void stop()

Stops the thread.

isAlive

public boolean isAlive()

Checks if DatabaseHandler is alive. It means that:
- the thread must exists
- the thread must be fully started and running (isStarted equals true). This condition is used to check if the thread is fully started or if it needs more time to start.

Returns:

true if the thread is fully started and operational, false otherwise

run

public void run()

Runs the thread.

Specified by:

run in interface java.lang.Runnable

setSamplingInterval

public void setSamplingInterval(int samplingInterval)

Sets the frequency of database maintenance.

Parameters:

samplingInterval - interval in miliseconds, how often the database maintenance will be performed

setClientId

public void setClientId(java.lang.String clientId)

Sets the client identifier. It will be placed in the database to distinguish databases coming from different clients on the server side.

Parameters:

clientId - the client identifier

setGlobalIP

public void setGlobalIP(java.lang.String globalIP)

Sets the global IP address of the client. It will be placed in the database in a hashed version.

Parameters:

globalIP - the global IP address

setNetworkName

public void setNetworkName(java.lang.String networkName)

Sets the network name. It will be placed in the database to distinguish databases coming from clients placed temporarily in different networks.

Parameters:

networkName - the network name

getSystemInfo

private static java.lang.String getSystemInfo()

Gets system information. It will be stored in the database together with client identifier. This allows to see on the server side what kind of hardware and software equipment is used by the client, and therefore, to compare the equipment with performance measurements.

Returns:

string of system information

setDatabase

private void setDatabase()

Sets the database. If the database does not exist, it creates the database and initializes the structure. If a database already exists, it closes the database and renames it to a fdb file, which will be automatically picked up by another thread and sent to the server. Then, it creates a new database and initializes its structure.

emptyStorage

public void emptyStorage()

Moves all the closed flows from the closed flows storage to the database. If the size of the database exceeds some limit after the transfer is finished, the new database is launched by setDatabase.

maintenance

private void maintenance()

Does the periodical maintenance. If number of closed flows or performance measurements exceeds some levels, the closed flows and performance measurements are transferred to the database.