org.objectweb.cjdbc.controller.connection
Class VariablePoolConnectionManager

java.lang.Object
  org.objectweb.cjdbc.controller.connection.AbstractConnectionManager
      org.objectweb.cjdbc.controller.connection.AbstractPoolConnectionManager
          org.objectweb.cjdbc.controller.connection.VariablePoolConnectionManager

All Implemented Interfaces:

java.lang.Cloneable, XmlComponent

public class VariablePoolConnectionManager

extends AbstractPoolConnectionManager

This connection manager provides connection pooling with a dynamically adjustable pool size.

If the maximum number of active connections is not reached, the getConnection()method creates a connection. Else, the execution is blocked until a connection is freed or the timeout expires. blocked until a connection is freed or the timeout expires.

Idle connections in the pool are removed after the timeout idleTimeout if the minimum pool size has not been reached.

Version:

1.0

Author:

Emmanuel Cecchet , Mathieu Peltier , Nicolas Modrzyk

Nested Class Summary

protected class

VariablePoolConnectionManager.RemoveIdleConnectionsThread Allows to remove idle free connections after the idleTimeout timeout.

Field Summary

static int	DEFAULT_IDLE_TIMEOUT Default idle timeout in milliseconds: default is 0 and means that once allocated, connections are never released.
static int	DEFAULT_MAX_POOL_SIZE Default maximum pool size: default is 0 and means no limit.
static int	DEFAULT_WAIT_TIMEOUT Default wait timeout in milliseconds: the default is 0 and means no timeout: waits until one connection is freed.
private int	idleTimeout Time a connection can stay idle before begin released (removed from the pool) in milliseconds (0 means forever)
private int	initPoolSize Initial pool size to be initialized at startup.
private int	maxPoolSize Maximum pool size.
private int	minPoolSize Minimum pool size.
private java.util.LinkedList	releaseTimes Stores the time on which connections have been released.
private VariablePoolConnectionManager.RemoveIdleConnectionsThread	removeIdleConnectionsThread Allow to remove idle connections in the pool.
private int	waitTimeout Maximum time to wait for a connection in milliseconds.

Fields inherited from class org.objectweb.cjdbc.controller.connection.AbstractPoolConnectionManager

activeConnections, freeConnections, poolSize

Fields inherited from class org.objectweb.cjdbc.controller.connection.AbstractConnectionManager

backendName, backendUrl, driverClassName, driverPath, initialized, logger, rLogin, rPassword

Fields inherited from interface org.objectweb.cjdbc.common.xml.XmlComponent

DOCTYPE_CONTROLLER, DOCTYPE_DB, XML_VERSION

Constructor Summary

VariablePoolConnectionManager(java.lang.String backendUrl, java.lang.String backendName, java.lang.String rLogin, java.lang.String rPassword, java.lang.String driverPath, java.lang.String driverClassName, int minPoolSize, int maxPoolSize, int idleTimeout, int waitTimeout)
Creates a new VariablePoolConnectionManager instance with the default minPoolSize(initial pool size to be initialized at startup).

VariablePoolConnectionManager(java.lang.String backendUrl, java.lang.String backendName, java.lang.String rLogin, java.lang.String rPassword, java.lang.String driverPath, java.lang.String driverClassName, int initPoolSize, int minPoolSize, int maxPoolSize, int idleTimeout, int waitTimeout)
Creates a new VariablePoolConnectionManager instance.

Method Summary

protected java.lang.Object	clone()
void	deleteConnection(java.sql.Connection c) Delete a connection that is no more valid.
void	finalizeConnections() Releases all the connections to the database.
java.sql.Connection	getConnection() Gets a connection from the pool.
int	getIdleTimeout() Gets the idle timeout.
int	getMaxPoolSize() Gets the max pool size.
int	getMinPoolSize() Gets the min pool size.
int	getWaitTimeout() Gets the wait timeout.
java.lang.String	getXmlImpl() Gets xml formatted information on this connection manager
void	initializeConnections() Initializes the connection(s) to the database.
void	releaseConnection(java.sql.Connection c) Releases a connection.

Methods inherited from class org.objectweb.cjdbc.controller.connection.AbstractPoolConnectionManager

getCurrentNumberOfConnections, initializeConnections

Methods inherited from class org.objectweb.cjdbc.controller.connection.AbstractConnectionManager

copy, deleteConnection, finalize, getConnection, getConnectionFromDriver, getDriverClassName, getDriverPath, getLogin, getPassword, getVLogin, getXml, isInitialized, releaseConnection, retrieveConnection, setDriverClassName, setDriverPath, setLogin, setPassword, setVLogin

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_MAX_POOL_SIZE

public static final int DEFAULT_MAX_POOL_SIZE

Default maximum pool size: default is 0 and means no limit.

See Also:

Constant Field Values

DEFAULT_IDLE_TIMEOUT

public static final int DEFAULT_IDLE_TIMEOUT

Default idle timeout in milliseconds: default is 0 and means that once allocated, connections are never released.

See Also:

Constant Field Values

DEFAULT_WAIT_TIMEOUT

public static final int DEFAULT_WAIT_TIMEOUT

Default wait timeout in milliseconds: the default is 0 and means no timeout: waits until one connection is freed.

See Also:

Constant Field Values

initPoolSize

private int initPoolSize

Initial pool size to be initialized at startup.

minPoolSize

private int minPoolSize

Minimum pool size.

maxPoolSize

private int maxPoolSize

Maximum pool size.

idleTimeout

private int idleTimeout

Time a connection can stay idle before begin released (removed from the pool) in milliseconds (0 means forever)

waitTimeout

private int waitTimeout

Maximum time to wait for a connection in milliseconds.

releaseTimes

private java.util.LinkedList releaseTimes

Stores the time on which connections have been released.

removeIdleConnectionsThread

private VariablePoolConnectionManager.RemoveIdleConnectionsThread removeIdleConnectionsThread

Allow to remove idle connections in the pool.

Constructor Detail

VariablePoolConnectionManager

public VariablePoolConnectionManager(java.lang.String backendUrl,
                                     java.lang.String backendName,
                                     java.lang.String rLogin,
                                     java.lang.String rPassword,
                                     java.lang.String driverPath,
                                     java.lang.String driverClassName,
                                     int minPoolSize,
                                     int maxPoolSize,
                                     int idleTimeout,
                                     int waitTimeout)

Creates a new VariablePoolConnectionManager instance with the default minPoolSize(initial pool size to be initialized at startup).

Parameters:

backendUrl - URL of the DatabaseBackend owning this connection manager

backendName - name of the DatabaseBackend owning this connection manager

rLogin - backend connection login to be used by this connection manager

rPassword - backend connection password to be used by this connection manager

driverPath - path for driver

driverClassName - class name for driver

minPoolSize - minimum pool size.

maxPoolSize - maximum pool size. 0 means no limit.

idleTimeout - time a connection can stay idle before begin released (removed from the pool) in seconds. 0 means no timeout: once allocated, connections are never released.

waitTimeout - maximum time to wait for a connection in seconds. 0 means no timeout: waits until one connection is freed.

VariablePoolConnectionManager

public VariablePoolConnectionManager(java.lang.String backendUrl,
                                     java.lang.String backendName,
                                     java.lang.String rLogin,
                                     java.lang.String rPassword,
                                     java.lang.String driverPath,
                                     java.lang.String driverClassName,
                                     int initPoolSize,
                                     int minPoolSize,
                                     int maxPoolSize,
                                     int idleTimeout,
                                     int waitTimeout)

Creates a new VariablePoolConnectionManager instance.

Parameters:

backendUrl - URL of the DatabaseBackend owning this connection manager

backendName - name of the DatabaseBackend owning this connection manager

rLogin - backend connection login to be used by this connection manager

rPassword - backend connection password to be used by this connection manager

driverPath - path for driver

driverClassName - class name for driver

initPoolSize - initial pool size to be intialized at startup

minPoolSize - minimum pool size.

maxPoolSize - maximum pool size. 0 means no limit.

idleTimeout - time a connection can stay idle before begin released (removed from the pool) in seconds. 0 means no timeout: once allocated, connections are never released.

waitTimeout - maximum time to wait for a connection in seconds. 0 means no timeout: waits until one connection is freed.

Method Detail

clone

protected java.lang.Object clone()
                          throws java.lang.CloneNotSupportedException

Specified by:

clone in class AbstractConnectionManager

Throws:

java.lang.CloneNotSupportedException

See Also:

Object.clone()

getMaxPoolSize

public int getMaxPoolSize()

Gets the max pool size.

Returns:

a int value.

getMinPoolSize

public int getMinPoolSize()

Gets the min pool size.

Returns:

a int value.

getIdleTimeout

public int getIdleTimeout()

Gets the idle timeout.

Returns:

a int value.

getWaitTimeout

public int getWaitTimeout()

Gets the wait timeout.

Returns:

a int value.

initializeConnections

public void initializeConnections()
                           throws java.sql.SQLException

Description copied from class: AbstractConnectionManager

Initializes the connection(s) to the database. The caller must ensure that the driver has already been loaded else an exception will be thrown.

Overrides:

initializeConnections in class AbstractPoolConnectionManager

Throws:

java.sql.SQLException

See Also:

AbstractPoolConnectionManager.initializeConnections()

finalizeConnections

public void finalizeConnections()
                         throws java.sql.SQLException

Description copied from class: AbstractConnectionManager

Releases all the connections to the database.

Overrides:

finalizeConnections in class AbstractPoolConnectionManager

Throws:

java.sql.SQLException

See Also:

AbstractConnectionManager.finalizeConnections()

getConnection

public java.sql.Connection getConnection()
                                  throws UnreachableBackendException

Gets a connection from the pool.

If the current number of active connections is lower than the maximum pool size, a new connection is created. If the creation fails, this method waits for a connection to be freed.

If the maximum number of active connections is reached, this methods blocks until a connection is freed or the timeout expires.

Specified by:

getConnection in class AbstractConnectionManager

Returns:

a connection from the pool or null if the timeout has expired.

Throws:

UnreachableBackendException - if the backend must be disabled

See Also:

AbstractConnectionManager.getConnection()

releaseConnection

public void releaseConnection(java.sql.Connection c)

Description copied from class: AbstractConnectionManager

Releases a connection.

Specified by:

releaseConnection in class AbstractConnectionManager

Parameters:

c - the connection to release.

See Also:

AbstractConnectionManager.releaseConnection(Connection)

deleteConnection

public void deleteConnection(java.sql.Connection c)

Description copied from class: AbstractConnectionManager

Delete a connection that is no more valid.

Specified by:

deleteConnection in class AbstractConnectionManager

Parameters:

c - the connection to delete.

See Also:

AbstractConnectionManager.deleteConnection(Connection)

getXmlImpl

public java.lang.String getXmlImpl()

Description copied from class: AbstractConnectionManager

Gets xml formatted information on this connection manager

Specified by:

getXmlImpl in class AbstractConnectionManager

Returns:

xml formatted string that conforms to c-jdbc.dtd

See Also:

AbstractConnectionManager.getXmlImpl()