com.lf.commons.db

Class DatabaseManager

java.lang.Object

com.lf.commons.db.DatabaseManager

Direct Known Subclasses:

SimpleDatabaseManager

public abstract class DatabaseManager
extends java.lang.Object

Manager class for common database functionality.

Many JDBC-compliant relational database management systems (RDBMS) so exist on the market. Although JDBC offers a very common approach, different databases behave different or the configuration steps are very different. This manager class sits on top of the JDBC API and provides common database functionalities like getting a connection from the pool, close unused connections after a certain timeout, update database schemas on the DDL level, convert result rows to default data structures like properties and much more.

The single databases can be deployed by Leisenfels applications by getting the appropriate connector up and running. Initially there will only be support for JavaDB (aka Derby) developed by IBM under the Apache license. Future versions of this manager class may provide support for additional databases like Oracle, DB2, PostgreSQL, HSQLDB etc.

Remember that the available drivers on the classpath are automatically determined by Java 1.6 (call to DriverManager.registerDriver() is not necessary).

Here, the term database connection stands for the level on which the connection parameters are collected (username, password, JDBC parameters etc.) while the connectors are responsible for connecting to the databases on the driver level. Connections are unique which means that they use a static (but configurable) data basis for the connectors. In order to implement a session concept it is possible to create as many connectors for each of the connections as required. The connection data basis is directly customized using the DatabaseConnectionDialog.

Since:

1.6

Version:

$Revision: 1.44 $, $Date: 2012/12/28 11:44:24 $

Author:

Axel Schwolow

Field Summary

Fields

Modifier and Type	Field and Description
protected java.util.Vector<java.lang.String[]>	backupSchemas List of schemas, includes, and excludes to perform user-space backup.
protected java.util.Hashtable<java.lang.String,DatabaseConnection>	cacheConnectionByID Container holding the various database connections by their unique identifiers.
protected java.util.Hashtable<java.lang.String,java.util.Vector<DatabaseConnector>>	cacheConnectorByConnectionID Container holding the various connectors by the connection's unique identifiers.
protected java.util.Hashtable<java.lang.Integer,DatabaseConnector>	cacheConnectorByConnectorID Container holding the various connectors by the unique identifiers.
protected java.util.Hashtable<java.lang.String,DatabaseConnectorDef>	cacheConnectorDefByType Container holding the supported database connector definitions by their class name.
protected java.util.Hashtable<java.lang.String,EmbeddedHandler>	cacheEmbeddedByType Container holding the installed handlers for embedded databases by their connector class name.
protected int	counterConnectorID Sequence generator for connector identifiers, starts with 1.
protected java.lang.String[]	inspectedSchemas List of schemas to be used for graph analysis.

Constructor Summary

Constructors

Constructor and Description
DatabaseManager() Constuctor method for the manager.

Method Summary

Methods

Modifier and Type	Method and Description
void	addBackupSchema(java.lang.String schema, java.lang.String includes, java.lang.String excludes) Adds a schema used for backing up the user-space (set by sub-classes).
void	addConnection(java.lang.String id, DatabaseConnection dbconn) Adds a new connection for a specific database system.
void	addConnectorDef(DatabaseConnectorDef connectordef) Adds a new connector definition providing if connector is supported and available.
void	addEmbeddedHandler(EmbeddedHandler handler) Adds a new handler for an embedded database.
void	addInspectedSchema(java.lang.String schema) Adds a schema used for graph analysis (set by sub-classes).
abstract boolean	changePassword(java.lang.String type, java.lang.String user, java.lang.String password) Changes the user password for the given embedded database.
abstract boolean	connect(DatabaseConnector connector, boolean updatecheck) Connects to the configured database.
abstract java.sql.Connection	createNewConnection(DatabaseConnector connector, java.lang.String jdbcurl) Lets the given connector create a new connection for the given JDBC URL.
DatabaseConnector	createNewConnector(DatabaseConnection dbconn, boolean force) Creates a fresh new connector for the given type.
abstract DatabaseTabbedSession	createNewSession(DatabaseConnection dbconn, boolean connect) Convenience method to create a new session.
protected int	createNextConnectorID() Generates the next unique connector identifier.
abstract boolean	disconnect(DatabaseConnector connector) Disconnects from the configured database.
protected void	finalize() Clean-up method to help the gc.
static DatabaseConnector[]	findConnectors(DatabaseConnector[] connectors, java.lang.Class clazz) Convenience method to find a certain collector implementation from a list of connectors.
abstract boolean	flushEmbedded(java.lang.String type) Flushes the given embedded database.
abstract boolean	freezeEmbedded(java.lang.String type) Freezes the given embedded database.
DatabaseConnection[]	getAllConnections() Provides the database connection configurations currently managed sorted by names.
DatabaseConnectorDef[]	getAllConnectorDefs() Provides all connector definitions.
DatabaseConnector[]	getAllConnectors() Provides all connectors currently installed.
protected EmbeddedHandler[]	getAllEmbeddedHandlers() Provides the handlers for embedded databases currently managed (internal use only).
java.util.Vector<java.lang.String[]>	getBackupSchemas() Provides the list of schemas used for backing up the user-space (set by sub-classes).
DatabaseConnection	getConnection(DatabaseConnector connector) Provides a database connection configuration.
DatabaseConnection	getConnection(java.lang.String id) Provides a database connection configuration.
java.lang.String	getConnectionName(DatabaseConnector connector) Provides a database connection configuration.
DatabaseConnection[]	getConnections(java.lang.String type) Provides the database connections for the given type currently managed sorted by names.
DatabaseConnector	getConnector(int id) Provides the connector for the unique numerical identifier.
DatabaseConnectorDef	getConnectorDef(java.lang.String clazz) Removes the connector definition providing if connector is supported and available.
int	getConnectorID(DatabaseConnector connector) Provides the unique identifier of the connection for the given connector.
DatabaseConnector[]	getConnectors(java.lang.String id) Provides the connectors for the given connection currently installed.
abstract java.lang.String	getDefaultConnectionURL(DatabaseConnector connector) Provides the JDBC URL for the default connection (normally a user connection).
protected EmbeddedHandler	getEmbeddedHandler(java.lang.String clazz) Provides a handler for an embedded database (internal use only).
DatabaseConnector	getFirstBestConnectedConnector(java.lang.String id) Provides the connectors for the given connection currently installed.
java.lang.String[]	getInspectedSchemas() Provides the list of schemas used for graph analysis (set by sub-classes).
java.lang.String	getUniqueConnectionID() Provides the next connection identifier unique for this manager.
DatabaseConnectorDef[]	getUsableConnectorDefs() Provides the connector definitions that are available and supported.
boolean	hasConnectorDef(java.lang.String clazz) Checks whether the given connector class is supported by this database manager.
boolean	hasEmbeddedHandler(java.lang.String clazz) Checks whether the given handler for an embedded database exists.
boolean	hasUsableConnectorDef(java.lang.String clazz) Checks whether the given connector class is available and supported.
boolean	isEmbedded(DatabaseConnector connector) Is the given connector designed for an embedded database like Java DB?
abstract boolean	isEmbeddedRunning(java.lang.String type) Is the embedded database management system currently running?
abstract boolean	isSchemaNewer(java.lang.String versionID1, java.lang.String versionID2) Checks whether the first schema version identifier is newer than the second.
void	printDebugConnections() Prints some debug information (connections).
void	removeAllConnections() Removes all installed connections from the internal container.
void	removeAllConnectorDefs() Removes all installed connector definitions providing if connector is supported and available.
void	removeConnection(DatabaseConnection dbconn) Removes the specified connection from the internal container.
void	removeConnection(java.lang.String id) Removes the specified connection from the internal container.
void	removeConnector(DatabaseConnector connector) Removes the given connector from the internal caches.
void	removeConnectorDef(DatabaseConnectorDef connectordef) Removes a connector definition providing if connector is supported and available.
void	removeConnectorDef(java.lang.String clazz) Removes a connector definition providing if connector is supported and available.
void	removeEmbeddedHandler(java.lang.String clazz) Removes a handler for an embedded database.
abstract boolean	reset(DatabaseConnector connector) Resets the connector for the configured database.
abstract boolean	startEmbedded(java.lang.String type) Starts the given embedded database.
abstract boolean	stopEmbedded(java.lang.String type) Stops the given embedded database.
abstract boolean	unfreezeEmbedded(java.lang.String type) Unfreezes the given embedded database.
abstract boolean	update(DatabaseConnector connector, SchemaProps schemaprops) Updates the database schema for the given connector.
void	updateConnections(java.util.Vector<DatabaseConnection> newconnections) Updates the managed connections with the new configurations.

Methods inherited from class java.lang.Object

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

Field Detail

cacheConnectionByID

protected java.util.Hashtable<java.lang.String,DatabaseConnection> cacheConnectionByID

Container holding the various database connections by their unique identifiers.

cacheConnectorByConnectionID

protected java.util.Hashtable<java.lang.String,java.util.Vector<DatabaseConnector>> cacheConnectorByConnectionID

Container holding the various connectors by the connection's unique identifiers.

cacheConnectorByConnectorID

protected java.util.Hashtable<java.lang.Integer,DatabaseConnector> cacheConnectorByConnectorID

Container holding the various connectors by the unique identifiers.

cacheConnectorDefByType

protected java.util.Hashtable<java.lang.String,DatabaseConnectorDef> cacheConnectorDefByType

Container holding the supported database connector definitions by their class name.

cacheEmbeddedByType

protected java.util.Hashtable<java.lang.String,EmbeddedHandler> cacheEmbeddedByType

Container holding the installed handlers for embedded databases by their connector class name.

backupSchemas

protected java.util.Vector<java.lang.String[]> backupSchemas

List of schemas, includes, and excludes to perform user-space backup.

inspectedSchemas

protected java.lang.String[] inspectedSchemas

List of schemas to be used for graph analysis.

counterConnectorID

protected int counterConnectorID

Sequence generator for connector identifiers, starts with 1.

Constructor Detail

DatabaseManager

public DatabaseManager()

Constuctor method for the manager.

Since:

1.6

Method Detail

finalize

protected void finalize()
                 throws java.lang.Throwable

Clean-up method to help the gc.

Overrides:

finalize in class java.lang.Object

Throws:

java.lang.Throwable - Error indication

Since:

1.6

addConnection

public void addConnection(java.lang.String id,
                 DatabaseConnection dbconn)

Adds a new connection for a specific database system.

The configuration to feed the connectors may be configured using a GUI.

Parameters:

id - The unique connection identifier

dbconn - The connection properties by DatabaseConnectionDialog

Throws:

java.lang.NullPointerException - If parameters are null

java.lang.IllegalArgumentException - If parameters are invalid

Since:

1.6

getConnection

public DatabaseConnection getConnection(java.lang.String id)

Provides a database connection configuration.

Parameters:

id - The unique connection identifier

Returns:

Installed connection or null otherwise

Throws:

java.lang.NullPointerException - If parameters are null

Since:

1.6

removeConnection

public void removeConnection(java.lang.String id)

Removes the specified connection from the internal container.

Parameters:

id - The unique connection identifier

Throws:

java.lang.NullPointerException - If parameters are null

Since:

1.6

removeConnection

public void removeConnection(DatabaseConnection dbconn)

Removes the specified connection from the internal container.

Parameters:

dbconn - The connection properties by DatabaseConnectionDialog

Throws:

java.lang.NullPointerException - If parameters are null

Since:

1.6

removeAllConnections

public void removeAllConnections()

Removes all installed connections from the internal container.

Since:

1.6

getAllConnections

public DatabaseConnection[] getAllConnections()

Provides the database connection configurations currently managed sorted by names.

Returns:

Connection array, possibly empty

Since:

1.6

getConnections

public DatabaseConnection[] getConnections(java.lang.String type)

Provides the database connections for the given type currently managed sorted by names.

Parameters:

type - The connector class type in FQN

Returns:

Connection array, possibly empty

Throws:

java.lang.NullPointerException - If parameters are null

Since:

1.6

getUniqueConnectionID

public java.lang.String getUniqueConnectionID()

Provides the next connection identifier unique for this manager.

Returns:

The unique identifier

Since:

1.6

updateConnections

public void updateConnections(java.util.Vector<DatabaseConnection> newconnections)

Updates the managed connections with the new configurations.

The connections are matched by their unique identifiers.

Parameters:

newconnections - The connections to be set

Throws:

java.lang.NullPointerException - If parameters are null

java.lang.IllegalArgumentException - If parameters are invalid

Since:

1.6

addConnectorDef

public void addConnectorDef(DatabaseConnectorDef connectordef)

Adds a new connector definition providing if connector is supported and available.

If a connector is requested by an application a valid definition requires to be existing. Normally the subclasses add the connector definitions appropriate for the application.

Parameters:

connectordef - The connector definition to be added

Throws:

java.lang.NullPointerException - If parameters are null

Since:

1.6

hasConnectorDef

public boolean hasConnectorDef(java.lang.String clazz)

Checks whether the given connector class is supported by this database manager.

Parameters:

clazz - The connector class

Returns:

Definition exists?

Throws:

java.lang.NullPointerException - If parameters are null

Since:

1.6

removeConnectorDef

public void removeConnectorDef(java.lang.String clazz)

Removes a connector definition providing if connector is supported and available.

Parameters:

clazz - The connector class

Throws:

java.lang.NullPointerException - If parameters are null

Since:

1.6

removeConnectorDef

public void removeConnectorDef(DatabaseConnectorDef connectordef)

Removes a connector definition providing if connector is supported and available.

Parameters:

connectordef - The connector definition to be added

Throws:

java.lang.NullPointerException - If parameters are null

Since:

1.6

removeAllConnectorDefs

public void removeAllConnectorDefs()

Removes all installed connector definitions providing if connector is supported and available.

Since:

1.6

getAllConnectorDefs

public DatabaseConnectorDef[] getAllConnectorDefs()

Provides all connector definitions.

Returns:

Connector definition array, possibly empty

Since:

1.6

getUsableConnectorDefs

public DatabaseConnectorDef[] getUsableConnectorDefs()

Provides the connector definitions that are available and supported.

Returns:

Connector definition array, possibly empty

Since:

1.6

hasUsableConnectorDef

public boolean hasUsableConnectorDef(java.lang.String clazz)

Checks whether the given connector class is available and supported.

Parameters:

clazz - The connector class

Returns:

Definition exists?

Throws:

java.lang.NullPointerException - If parameters are null

Since:

1.6

getConnectorDef

public DatabaseConnectorDef getConnectorDef(java.lang.String clazz)

Removes the connector definition providing if connector is supported and available.

Parameters:

clazz - The connector class

Returns:

The connector definition

Throws:

java.lang.NullPointerException - If parameters are null

Since:

1.6

createNewConnector

public DatabaseConnector createNewConnector(DatabaseConnection dbconn,
                                   boolean force)

Creates a fresh new connector for the given type.

Each connector is associated with its connection and remembered here. It must be removed manually if it is not needed any longer. The given database connection must have been added using addConnection() before.

Parameters:

dbconn - The connection

force - Do not check if the connection has been added (required for connection management)

Returns:

The new connector

Throws:

java.lang.NullPointerException - If parameters are null

java.lang.IllegalArgumentException - If a parameter is invalid

Since:

1.6

removeConnector

public void removeConnector(DatabaseConnector connector)

Removes the given connector from the internal caches.

Parameters:

connector - The connector

Throws:

java.lang.NullPointerException - If parameters are null

java.lang.IllegalArgumentException - If a parameter is invalid

Since:

1.6

getConnectionName

public java.lang.String getConnectionName(DatabaseConnector connector)

Provides a database connection configuration.

Parameters:

connector - The connector

Returns:

Connection name, may be null

Throws:

java.lang.NullPointerException - If parameters are null

Since:

1.6

getConnection

public DatabaseConnection getConnection(DatabaseConnector connector)

Provides a database connection configuration.

Parameters:

connector - The connector

Returns:

Connection, may be null

Throws:

java.lang.NullPointerException - If parameters are null

Since:

1.6

addEmbeddedHandler

public void addEmbeddedHandler(EmbeddedHandler handler)

Adds a new handler for an embedded database.

Parameters:

handler - The handler to be added

Throws:

java.lang.NullPointerException - If parameters are null

Since:

1.6

hasEmbeddedHandler

public boolean hasEmbeddedHandler(java.lang.String clazz)

Checks whether the given handler for an embedded database exists.

Parameters:

clazz - The supported connector class

Returns:

Definition exists?

Throws:

java.lang.NullPointerException - If parameters are null

Since:

1.6

removeEmbeddedHandler

public void removeEmbeddedHandler(java.lang.String clazz)

Removes a handler for an embedded database.

Parameters:

clazz - The connector class

Throws:

java.lang.NullPointerException - If parameters are null

Since:

1.6

getEmbeddedHandler

protected EmbeddedHandler getEmbeddedHandler(java.lang.String clazz)

Provides a handler for an embedded database (internal use only).

Use the manager methods to control the embedded database instead.

Parameters:

clazz - The supported connector class

Returns:

The handler, may be null

Throws:

java.lang.NullPointerException - If parameters are null

Since:

1.6

getAllEmbeddedHandlers

protected EmbeddedHandler[] getAllEmbeddedHandlers()

Provides the handlers for embedded databases currently managed (internal use only).

Use the manager methods to control the embedded database instead.

Returns:

Handler array, possibly empty

Since:

1.6

getConnectorID

public int getConnectorID(DatabaseConnector connector)

Provides the unique identifier of the connection for the given connector.

Parameters:

connector - The database connector

Returns:

Connector identifier, -1 otherwise

Since:

1.6

getConnector

public DatabaseConnector getConnector(int id)

Provides the connector for the unique numerical identifier.

Parameters:

id - The connector id

Returns:

Connector, may be null

Since:

1.6

getAllConnectors

public DatabaseConnector[] getAllConnectors()

Provides all connectors currently installed.

Returns:

Connector array, possibly empty

Since:

1.6

getConnectors

public DatabaseConnector[] getConnectors(java.lang.String id)

Provides the connectors for the given connection currently installed.

Parameters:

id - The connection identifier

Returns:

Connector array, possibly empty

Throws:

java.lang.NullPointerException - If parameters are null

Since:

1.6

getFirstBestConnectedConnector

public DatabaseConnector getFirstBestConnectedConnector(java.lang.String id)

Provides the connectors for the given connection currently installed.

Parameters:

id - The connection identifier

Returns:

Connector, may be null

Throws:

java.lang.NullPointerException - If parameters are null

Since:

1.6

findConnectors

public static DatabaseConnector[] findConnectors(DatabaseConnector[] connectors,
                                 java.lang.Class clazz)

Convenience method to find a certain collector implementation from a list of connectors.

Parameters:

connectors - The database connectors

clazz - The desired connector class

Returns:

Matching connectors, may be empty

Throws:

java.lang.NullPointerException - If parameters are invalid

Since:

1.6

addBackupSchema

public void addBackupSchema(java.lang.String schema,
                   java.lang.String includes,
                   java.lang.String excludes)

Adds a schema used for backing up the user-space (set by sub-classes).

The default schema names may be overriden by the connectors in order to be able to use any schema the user likes for external databases. The schema list is also used by the DatabaseData class to export/import database contents.

Parameters:

schema - The schema

includes - The regex for tables to be included, all if null

excludes - The regex for tables to be excluded, none if null

Throws:

java.lang.NullPointerException - If parameters are null

Since:

1.6

getBackupSchemas

public java.util.Vector<java.lang.String[]> getBackupSchemas()

Provides the list of schemas used for backing up the user-space (set by sub-classes).

Returns:

The backup schemas

Since:

1.6

addInspectedSchema

public void addInspectedSchema(java.lang.String schema)

Adds a schema used for graph analysis (set by sub-classes).

Parameters:

schema - The schema

Throws:

java.lang.NullPointerException - If parameters are null

Since:

1.6

printDebugConnections

public void printDebugConnections()

Prints some debug information (connections).

Since:

1.6

getInspectedSchemas

public java.lang.String[] getInspectedSchemas()

Provides the list of schemas used for graph analysis (set by sub-classes).

Returns:

The inspected schemas

Since:

1.6

createNextConnectorID

protected int createNextConnectorID()

Generates the next unique connector identifier.

Returns:

The inspected schemas

Since:

1.6

isEmbedded

public boolean isEmbedded(DatabaseConnector connector)

Is the given connector designed for an embedded database like Java DB?

Parameters:

connector - The database connector

Returns:

Embedded database?

Since:

1.6

getDefaultConnectionURL

public abstract java.lang.String getDefaultConnectionURL(DatabaseConnector connector)

Provides the JDBC URL for the default connection (normally a user connection).

Typical JDBC URLs look like "jdbc:derby://localhost:1527/lima".

Parameters:

connector - The connector

Returns:

The JDBC URL for the default connection, null if an error occurs

Throws:

java.lang.NullPointerException - If the parameters are null

Since:

1.6

connect

public abstract boolean connect(DatabaseConnector connector,
              boolean updatecheck)

Connects to the configured database.

Here, the application specific database manager has the chance to update menues etc. This method should be preferred, do not use the DatabaseConnector.connect() method directly. Asks the user for the user credentials if required and not configured.

Typical JDBC URLs look like "jdbc:derby://localhost:1527/lima".

Parameters:

connector - The connector

updatecheck - Update database if necessary

Returns:

Connection established?

Throws:

java.lang.NullPointerException - If the parameters are null

Since:

1.6

disconnect

public abstract boolean disconnect(DatabaseConnector connector)

Disconnects from the configured database.

Here, the application specific database manager has the chance to reset the passwords etc. This method should be preferred, do not use the DatabaseConnector.disconnect() method directly.

Parameters:

connector - The connector

Returns:

Successfully disconnected?

Throws:

java.lang.NullPointerException - If the parameters are null

Since:

1.6

reset

public abstract boolean reset(DatabaseConnector connector)

Resets the connector for the configured database.

Here, the application specific database manager has the chance to reset the password etc.

Parameters:

connector - The connector

Returns:

Successfully reset?

Throws:

java.lang.NullPointerException - If the parameters are null

Since:

1.6

createNewConnection

public abstract java.sql.Connection createNewConnection(DatabaseConnector connector,
                                      java.lang.String jdbcurl)

Lets the given connector create a new connection for the given JDBC URL.

Here, the application specific database manager has the chance to change the schema etc.

Parameters:

connector - The connector

jdbcurl - The JDBC URL

Returns:

Connection for the database, may be null if an error occurred

Throws:

java.lang.NullPointerException - If the parameters are null

Since:

1.6

isSchemaNewer

public abstract boolean isSchemaNewer(java.lang.String versionID1,
                    java.lang.String versionID2)

Checks whether the first schema version identifier is newer than the second.

Applications can use any version id it wants. This can be simple numerical values or dates. The application specific manager implementation has the chance to process its identifiers correctly.

Parameters:

versionID1 - The first version identifier

versionID2 - The second version identifier

Returns:

First schema version identifier newer than the second?

Throws:

java.lang.NullPointerException - If the parameters are null

Since:

1.6

update

public abstract boolean update(DatabaseConnector connector,
             SchemaProps schemaprops)

Updates the database schema for the given connector.

Parameters:

connector - The connector to use, should be already connected

schemaprops - The schema properties

Returns:

Update successful?

isEmbeddedRunning

public abstract boolean isEmbeddedRunning(java.lang.String type)

Is the embedded database management system currently running?

Parameters:

type - The connector class name in FQN

Returns:

Database currently running?

Since:

1.6

startEmbedded

public abstract boolean startEmbedded(java.lang.String type)

Starts the given embedded database.

Parameters:

type - The connector class name in FQN

Returns:

Database successfully started?

Since:

1.6

stopEmbedded

public abstract boolean stopEmbedded(java.lang.String type)

Stops the given embedded database.

Parameters:

type - The connector class name in FQN

Returns:

Database successfully stopped?

Since:

1.6

flushEmbedded

public abstract boolean flushEmbedded(java.lang.String type)

Flushes the given embedded database.

Parameters:

type - The connector class name in FQN

Returns:

Database successfully flushed?

Since:

1.6

freezeEmbedded

public abstract boolean freezeEmbedded(java.lang.String type)

Freezes the given embedded database.

Parameters:

type - The connector class name in FQN

Returns:

Database successfully freezed?

Since:

1.6

unfreezeEmbedded

public abstract boolean unfreezeEmbedded(java.lang.String type)

Unfreezes the given embedded database.

Parameters:

type - The connector class name in FQN

Returns:

Database successfully unfreezed?

Since:

1.6

changePassword

public abstract boolean changePassword(java.lang.String type,
                     java.lang.String user,
                     java.lang.String password)

Changes the user password for the given embedded database.

Parameters:

type - The connector class name in FQN

user - The database user

password - The new password

Returns:

Change was successful?

Since:

1.6

createNewSession

public abstract DatabaseTabbedSession createNewSession(DatabaseConnection dbconn,
                                     boolean connect)

Convenience method to create a new session.

Parameters:

dbconn - The connection to use

connect - Connect to database

Returns:

The new session, may be null

Since:

1.6