Package com.storedobject.core

Class SQLConnector

java.lang.Object

com.storedobject.core.SQLConnector

Direct Known Subclasses:

SQLConnector

public abstract class SQLConnector
extends Object

The database driver interface. In order to write a database driver that works with the stored objects system, one of the tasks is to create a concrete class that extends this abstract class. The class should be packaged in a package like "com.storedobject.database.DDD" where DDD is the name of the database driver. For example, the Sybase Adaptive Server Enterprise driver package is "com.storedobject.database.ase" and the Oracle driver package is "com.storedobject.database.oracle".

Author:

Syam

See Also:

• DatabaseDriver
• Database

Field Summary

Fields

Modifier and Type	Field	Description
protected static Properties	connectionProperties	The connection properties used to connect to the database via JDBC driver.
protected static String	connectionString	The connection string used to connect via the JDBC driver.
protected static String	database	The name of the database.
protected static String	databaseMaster	The name of the database master.
static boolean	debug

Constructor Summary

Constructors

Constructor	Description
SQLConnector()	Constructor that initializes the necessary stuff.

Method Summary

Modifier and Type	Method	Description
protected boolean	canCancel()	See if canceling of a connection is possible or not.
protected void	cancelConnection(com.storedobject.core.SQLConnector.DBConnection c)	Cancels a given SQL connection.
static void	changePassword(String oldPassword, String newPassword)	A call to this method needs to be made whenever the password is changed.
protected void	closeConnection(com.storedobject.core.SQLConnector.DBConnection c)	Closes a given SQL connection.
protected com.storedobject.core.SQLConnector.DBConnection	createConnection(boolean master)	Create a new SQL connection.
protected abstract Process	doDataDump(String securityPassword, boolean sql, String dbName)
protected abstract Process	doDataRestore(String securityPassword, String dbName)
static void	dumpDebugInfo()	Dump debug information on busy connections older than 5 minutes.
static void	dumpDebugInfo(int ageInMinutes)	Dump debug information on busy connections.
protected static int	getBusyConnectionCount()	Gets the number of busy connections as of now.
final com.storedobject.core.SQLConnector.DBConnection	getConnection(RawSQL sql, boolean master)	Gets a connection.
static String	getDatabaseMasterName()	Gets the name of the database master.
static String	getDatabaseName()	Gets the name of the database.
static List<String>	getDebugInfo()	Get debug information on busy connections older than 5 minutes.
static List<String>	getDebugInfo(int ageInMinutes)	Get debug information on busy connections.
protected final Exception	getException(String message)	Gets an equivalent exception from the StoredObject system.
protected static int	getFreeConnectionCount()	Gets the number of free connections available in the pool as of now.
static Logger	getLogger()
static int	getPoolSize()	Gets the current connection pool size.
static Statement	getStatement(String user, String password)	Gets a statement object for execution of SQL for a particular login/password pair.
protected boolean	handleError(int code)	Handles errors.
final void	handleException(SQLException w)	Handles all SQL exceptions from SQL statement execution.
protected boolean	handleSQLMessage(String message)	Handles SQL error message.
protected boolean	handleSQLState(String state)	Handles SQL states.
static void	log(String message)
static void	releaseAllConnections()	This method releases all SQL connections.
final void	releaseConnection(com.storedobject.core.SQLConnector.DBConnection connection)	This method releases a given SQL connection.
static void	setLogger(Logger logger)
static void	setPoolSize(int size)	Sets the pool size for the connection pool.

Methods inherited from class java.lang.Object

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

Field Details

debug

public static boolean debug

database

protected static String database

The name of the database. This value may be set by the derived class.

databaseMaster

protected static String databaseMaster

The name of the database master. This value may be set by the derived class. This could be same as database.

connectionString

protected static String connectionString

The connection string used to connect via the JDBC driver. This value MUST be set by the derived class.

connectionProperties

protected static Properties connectionProperties

The connection properties used to connect to the database via JDBC driver. The necessary property values MUST be set by the derived class.

Constructor Details

SQLConnector

public SQLConnector()

Constructor that initializes the necessary stuff.

Method Details

getLogger

public static Logger getLogger()

setLogger

public static void setLogger(Logger logger)

log

public static void log(String message)

setPoolSize

public static void setPoolSize(int size)

Sets the pool size for the connection pool.

Parameters:

size - Maximum number of connections to be kept alive.

getPoolSize

public static int getPoolSize()

Gets the current connection pool size.

Returns:

Pool size.

changePassword

public static void changePassword(String oldPassword,
 String newPassword)

A call to this method needs to be made whenever the password is changed.

Parameters:

oldPassword - Old password.

newPassword - New password.

getDatabaseName

public static String getDatabaseName()

Gets the name of the database.

Returns:

The database name.

getDatabaseMasterName

public static String getDatabaseMasterName()

Gets the name of the database master.

Returns:

The database master name.

releaseAllConnections

public static void releaseAllConnections()

This method releases all SQL connections.

releaseConnection

public final void releaseConnection(com.storedobject.core.SQLConnector.DBConnection connection)

This method releases a given SQL connection.

Parameters:

connection - The connection to be released.

getConnection

public final com.storedobject.core.SQLConnector.DBConnection getConnection(RawSQL sql,
 boolean master)

Gets a connection. If a free connection is available in the pool, that will be returned. Otherwise, a new connection is created and returned.

Parameters:

sql - Associated RawSQL instance.

master - Whether master or not.

Returns:

A SQL connection.

getDebugInfo

public static List<String> getDebugInfo()

Get debug information on busy connections older than 5 minutes.

Returns:

Stack trace information of busy connections.

getDebugInfo

public static List<String> getDebugInfo(int ageInMinutes)

Get debug information on busy connections.

Parameters:

ageInMinutes - Age in minutes.

Returns:

Stack trace information of busy connections.

dumpDebugInfo

public static void dumpDebugInfo()

Dump debug information on busy connections older than 5 minutes.

dumpDebugInfo

public static void dumpDebugInfo(int ageInMinutes)

Dump debug information on busy connections.

Parameters:

ageInMinutes - Age in minutes.

getStatement

public static Statement getStatement(String user,
 String password)
                              throws Exception

Gets a statement object for execution of SQL for a particular login/password pair.

Parameters:

user - The name of the user.

password - The password.

Returns:

The statement object.

Throws:

Exception - If any database error occurs.

getBusyConnectionCount

protected static int getBusyConnectionCount()

Gets the number of busy connections as of now.

Returns:

The number of busy connections.

getFreeConnectionCount

protected static int getFreeConnectionCount()

Gets the number of free connections available in the pool as of now.

Returns:

The number of free connections.

createConnection

protected com.storedobject.core.SQLConnector.DBConnection createConnection(boolean master)

Create a new SQL connection.

Parameters:

master - Whether to create a master connection or not.

Returns:

The newly created SQL connection.

closeConnection

protected void closeConnection(com.storedobject.core.SQLConnector.DBConnection c)

Closes a given SQL connection.

Parameters:

c - The connection to close.

cancelConnection

protected void cancelConnection(com.storedobject.core.SQLConnector.DBConnection c)

Cancels a given SQL connection.

Parameters:

c - The connection to cancel.

canCancel

protected boolean canCancel()

See if canceling of a connection is possible or not. (Some databases do not support/implement cancel operation).

Returns:

True if cancel is possible. Otherwise, false. The default is "false".

handleError

protected boolean handleError(int code)
                       throws Exception

Handles errors. Any database error can cause the generation of an error code. This method is called when such errors occur. If the error needs to be ignored, this method can return "true".

Parameters:

code - The error code.

Returns:

True if the error needs to be ignored, otherwise false. The default behaviour is to return "false".

Throws:

Exception - It can raise another exception to redirect the exception handling.

handleSQLState

protected boolean handleSQLState(String state)
                          throws Exception

Handles SQL states. Any database error can cause the generation of a SQL state code. This method is called when such errors occur. If the error needs to be ignored, this method can return "true".

Parameters:

state - The SQL state code.

Returns:

True if the error needs to be ignored, otherwise false. The default behaviour is to return "false".

Throws:

Exception - It can raise another exception to redirect the exception handling.

handleSQLMessage

protected boolean handleSQLMessage(String message)
                            throws Exception

Handles SQL error message. Any database error can cause the generation of a SQL error message. This method is called when such errors occur. If the error needs to be ignored, this method can return "true".

Parameters:

message - The SQL error message.

Returns:

True if the error needs to be ignored, otherwise false. The default behaviour is to return "false".

Throws:

Exception - It can raise another exception to redirect the exception handling.

handleException

public final void handleException(SQLException w)
                           throws Error_Running_SQL

Handles all SQL exceptions from SQL statement execution.

Parameters:

w - The SQL exception.

Throws:

Error_Running_SQL - It can throw exceptions with error details.

getException

protected final Exception getException(String message)

Gets an equivalent exception from the StoredObject system. For example, a database error message like "Account Not Found" will throw an Account_Not_Found() exception.

Parameters:

message - The message to translate to an exception.

Returns:

The exception value.

doDataDump

protected abstract Process doDataDump(String securityPassword,
 boolean sql,
 String dbName)

doDataRestore

protected abstract Process doDataRestore(String securityPassword,
 String dbName)