org.apache.xalan.lib.sql
Class DefaultConnectionPool

java.lang.Object
  org.apache.xalan.lib.sql.DefaultConnectionPool

All Implemented Interfaces:

ConnectionPool

public class DefaultConnectionPool
extends java.lang.Object
implements ConnectionPool

For internal connectiones, i.e. Connection information supplies in the Stylesheet. The Default Connection Pool will be used.

Field Summary

private static boolean	DEBUG
private java.util.Properties	m_ConnectionProtocol Always implement the properties mechinism, if the Password or Username is set seperatly then we will add them to the property manually.
private java.lang.String	m_driver The basic information to make a JDBC Connection
private java.sql.Driver	m_Driver A placeholder thast will keep the driver loaded between calls.
private boolean	m_IsActive Are we active ??
private java.util.Vector	m_pool Storage for the PooledConnections
private int	m_PoolMinSize The mimimum size of the connection pool, if the number of available connections falls below this mark, min connections will be allocated.
private java.lang.String	m_url

Constructor Summary

DefaultConnectionPool()

Method Summary

private void	addConnection(PooledConnection value)
private java.sql.Connection	createConnection()
protected void	finalize()
void	freeUnused() Go through the connection pool and release any connections that are not InUse;
java.sql.Connection	getConnection() Retrive a database connection from the pool
boolean	hasActiveConnections() Is our ConnectionPool have any connections that are still in Use ??
void	initializePool()
boolean	isEnabled() Return our current Active state
void	releaseConnection(java.sql.Connection con) Return a connection to the pool, the connection may be closed if the pool is inactive or has exceeded the max number of free connections
void	releaseConnectionOnError(java.sql.Connection con) Provide a mechinism to return a connection to the pool on Error.
void	setDriver(java.lang.String d) Set the driver call to be used to create connections
void	setMinConnections(int n) Override the current number of connections to keep in the pool.
void	setPassword(java.lang.String p) Set the password in the property set.
void	setPoolEnabled(boolean flag) The Pool can be Enabled and Disabled.
void	setProtocol(java.util.Properties p) The Protocol string is used to pass in other connection properties.
void	setURL(java.lang.String url) Set the url used to connect to the database
void	setUser(java.lang.String u) Set the user name in the property set
boolean	testConnection() Try to aquire a new connection, if it succeeds then return true, else return false.

Methods inherited from class java.lang.Object

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

Field Detail

m_Driver

private java.sql.Driver m_Driver

A placeholder thast will keep the driver loaded between calls.

DEBUG

private static final boolean DEBUG

See Also:

Constant Field Values

m_driver

private java.lang.String m_driver

The basic information to make a JDBC Connection

m_url

private java.lang.String m_url

m_PoolMinSize

private int m_PoolMinSize

The mimimum size of the connection pool, if the number of available connections falls below this mark, min connections will be allocated. The Connection Pool will always be somewhere between MinSize and MinSize*2

m_ConnectionProtocol

private java.util.Properties m_ConnectionProtocol

Always implement the properties mechinism, if the Password or Username is set seperatly then we will add them to the property manually.

m_pool

private java.util.Vector m_pool

Storage for the PooledConnections

m_IsActive

private boolean m_IsActive

Are we active ??

Constructor Detail

DefaultConnectionPool

public DefaultConnectionPool()

Method Detail

isEnabled

public boolean isEnabled()

Return our current Active state

Specified by:

isEnabled in interface ConnectionPool

setDriver

public void setDriver(java.lang.String d)

Set the driver call to be used to create connections

Specified by:

setDriver in interface ConnectionPool

Parameters:

d -

setURL

public void setURL(java.lang.String url)

Set the url used to connect to the database

Specified by:

setURL in interface ConnectionPool

Parameters:

url -

freeUnused

public void freeUnused()

Go through the connection pool and release any connections that are not InUse;

Specified by:

freeUnused in interface ConnectionPool

hasActiveConnections

public boolean hasActiveConnections()

Is our ConnectionPool have any connections that are still in Use ??

Specified by:

hasActiveConnections in interface ConnectionPool

setPassword

public void setPassword(java.lang.String p)

Set the password in the property set.

Specified by:

setPassword in interface ConnectionPool

Parameters:

p -

setUser

public void setUser(java.lang.String u)

Set the user name in the property set

Specified by:

setUser in interface ConnectionPool

Parameters:

u -

setProtocol

public void setProtocol(java.util.Properties p)

The Protocol string is used to pass in other connection properties. A properties file is a general purpose container

Specified by:

setProtocol in interface ConnectionPool

Parameters:

p -

setMinConnections

public void setMinConnections(int n)

Override the current number of connections to keep in the pool. This setting will only have effect on a new pool or when a new connection is requested and there is less connections that this setting.

Specified by:

setMinConnections in interface ConnectionPool

Parameters:

n -

testConnection

public boolean testConnection()

Try to aquire a new connection, if it succeeds then return true, else return false. Note: This method will cause the connection pool to be built.

Specified by:

testConnection in interface ConnectionPool

getConnection

public java.sql.Connection getConnection()
                                  throws java.lang.IllegalArgumentException,
                                         java.sql.SQLException

Description copied from interface: ConnectionPool

Retrive a database connection from the pool

Specified by:

getConnection in interface ConnectionPool

Returns:

Connection

Throws:

java.sql.SQLException

java.lang.IllegalArgumentException

releaseConnection

public void releaseConnection(java.sql.Connection con)
                       throws java.sql.SQLException

Description copied from interface: ConnectionPool

Return a connection to the pool, the connection may be closed if the pool is inactive or has exceeded the max number of free connections

Specified by:

releaseConnection in interface ConnectionPool

Parameters:

con -

Throws:

java.sql.SQLException

releaseConnectionOnError

public void releaseConnectionOnError(java.sql.Connection con)
                              throws java.sql.SQLException

Description copied from interface: ConnectionPool

Provide a mechinism to return a connection to the pool on Error. A good default behaviour is to close this connection and build a new one to replace it. Some JDBC impl's won't allow you to reuse a connection after an error occurs.

Specified by:

releaseConnectionOnError in interface ConnectionPool

Parameters:

con -

Throws:

java.sql.SQLException

createConnection

private java.sql.Connection createConnection()
                                      throws java.sql.SQLException

Throws:

java.sql.SQLException

initializePool

public void initializePool()
                    throws java.lang.IllegalArgumentException,
                           java.sql.SQLException

Throws:

java.lang.IllegalArgumentException

java.sql.SQLException

addConnection

private void addConnection(PooledConnection value)

Parameters:

value -

finalize

protected void finalize()
                 throws java.lang.Throwable

Overrides:

finalize in class java.lang.Object

Throws:

java.lang.Throwable

setPoolEnabled

public void setPoolEnabled(boolean flag)

The Pool can be Enabled and Disabled. Disabling the pool closes all the outstanding Unused connections and any new connections will be closed upon release.

Specified by:

setPoolEnabled in interface ConnectionPool

Parameters:

flag - Control the Connection Pool. If it is enabled then Connections will actuall be held around. If disabled then all unused connections will be instantly closed and as connections are released they are closed and removed from the pool.