StatelessConnectionPool Class

This class represents a pool of stateless, authenticated connections to the database.

Table 12-40 Enumerated Values Used by StatelessConnectionPool Class

Attribute	Options
PoolType	`HETEROGENEOUS` is the default state; connections with different authentication contexts can be created in the same pool. `HOMOGENEOUS` indicates that all connections in the pool will be authenticated with the username and password provided during pool creation. No proxy connections can be created. `minConn` and `incrConn` values are considered only in these `HOMOGENEOUS` pools.
BusyOption	`WAIT` indicates that the thread waits and blocks until the connection becomes free. `NOWAIT` throws and error. `FORGET` indicates that a new connection will be created, even when maximum number of connections is opened and all are busy.
DestroyMode	`DEFAULT` indicates that if are still active busy connections in the pool, `ORA24422` error is thrown `SPD_FORCE` indicates that the means that any busy connections in the pool will be forcefully terminated and the pool destroyed (the user will lose memory corresponding to the number of connections forcefully terminated)

Table 12-41 Summary of StatelessConnectionPool Methods

Method	Description
getAnyTaggedConnection()	Returns a pointer to the connection object, without the restriction of a matching tag.
getAnyTaggedProxyConnection()	Returns a proxy connection from a connection pool.
getBusyConnections()	Returns the number of busy connections in the connection pool.
getBusyOption()	Returns the behavior of the stateless connection pool when all the connections in the pool are busy and the number of connections have reached maximum
getConnection()	Returns a pointer to the `Connection` object.
getIncrConnections()	Returns the number of incremental connections in the connection pool.
getMaxConnections()	Returns the maximum number of connections in the connection pool.
getMinConnections()	Returns the minimum number of connections in the connection pool.
getOpenConnections()	Returns the number of open connections in the connection pool.
getPoolName()	Returns the name of the connection pool.
getProxyConnection()	Returns a proxy connection from a connection pool.
getTimeOut()	Returns the timeout period of a connection in the connection pool.
releaseConnection()	Releases the connection back to the pool with an optional tag.
setBusyOption()	Specifies the behavior of the stateless connection pool when: all the connections in the pool are busy, and the number of connections have reached maximum.
setPoolSize()	Sets the maximum, minimum, and incremental number of pooled connections for the connection pool.
setTimeOut()	Sets the timeout period of a connection in the connection pool.
terminateConnection()	Closes the connection and remove it from the pool.

getAnyTaggedConnection()

Returns a pointer to the connection object, without the restriction of a matching tag.

During the execution of this call, the pool is first searched based on the tag provided. If a connection with the specified tag exists, it is returned to the user. If a matching connection is not available, an appropriately authenticated untagged connection (with a NULL tag) is returned. In cases where an undated connection is not free, an appropriately authenticated connection with a different tag is returned.

Note:

A getTag() call to the Connection verifies the connection tag received.

Syntax	Description
Connection *getAnyTaggedConnection( string &tag="")=0;	Returns a pointer to the connection object from a homogeneous stateless connection pool, without the restriction of a matching tag; `string` support.
Connection* getAnyTaggedConnection( const UString &tag)=0;	Returns a pointer to the connection object from a homogeneous stateless connection pool, without the restriction of a matching tag; `UString` support.
Connection *getAnyTaggedConnection( const string &userNname, const string &password, const string &tag="")=0;	Returns a pointer to the connection object from a heterogeneous stateless connection pool, without the restriction of a matching tag; `string` support.
Connection* getAnyTaggedConnection( const UString &userName, const UString &Password, const UString &tag)=0 ;	Returns a pointer to the connection object from a heterogeneous stateless connection pool, without the restriction of a matching tag; `UString` support.

Parameter	Description
userName	The database username
password	The database password.
tag	User-defined type of connection requested. This parameter can be ignored if a default connection is requested.

getAnyTaggedProxyConnection()

Returns a proxy connection from a connection pool.

During the execution of this call, the pool is first searched based on the tag provided. If a connection with the specified tag exists, it is returned to the user. If a matching connection is not available, an appropriately authenticated connection with a different tag is returned. In cases where an undated connection is not free, an appropriately authenticated connection with a different tag is returned.

Restrictions for matching the tag may be removed by passing an empty tag argument parameter.

Note:

A getTag() call to the connection verifies the connection tag received.

Syntax	Description
Connection *getAnyTaggedProxyConnection( const string &name, string roles[], unsigned int numRoles, const string tag="", Connection::ProxyType proxyType=Connection::PROXY_DEFAULT);	Get a proxy connection with role specifications from a connection pool; includes support for roles and `string` support.
Connection* getAnyTaggedProxyConnection( const UString &name, string roles[], unsigned int numRoles, const UString &tag, Connection::ProxyType proxyType = Connection::PROXY_DEFAULT);	Get a proxy connection with role specifications from a connection pool; includes support for roles and `UString` support.
Connection *getAnyTaggedProxyConnection( const string &name, const string tag="", Connection::ProxyType proxyType=Connection::PROXY_DEFAULT);	Get a proxy connection with role specifications from a connection pool; `string` support.
Connection* getAnyTaggedProxyConnection( const UString &name, const UString &tag, Connection::ProxyType proxyType = Connection::PROXY_DEFAULT);	Get a proxy connection within role specifications from the connection pool; `UString` support.

Parameter	Description
name	The username.
roles	The roles to activate on the database server
numRoles	The number of roles to activate on the database server
tag	User defined tag associated with the connection.
proxyType	The type of proxy authentication to perform; `ProxyType` is defined in Table 12-11.

getBusyConnections()

Returns the number of busy connections in the connection pool.

Syntax

unsigned int getBusyConnections() const=0;

getBusyOption()

Returns the behavior of the stateless connection pool when all the connections in the pool are busy, and when the number of connections have reached maximum. The return values are defined for BusyOption in Table 12-40.

Syntax

BusyOption getBusyOption()=0;

getConnection()

Returns a pointer to the connection object of a StatelessConnectionPool.

Syntax	Description
Connection *getConnection( string &tag="")=0;	Returns an authenticated connection, with a connection pool username and password; `string` support.
Connection* getConnection( const UString &tag)=0;	Returns an authenticated connection, with a connection pool username and password; `UString` support.
Connection *getConnection( const string &userName, const string &password, const string &tag="")=0;	Returns a pointer to the connection object from a heterogeneous stateless connection pool; `string` support..
Connection* getConnection( const UString &userName, const UString &password, const UString &tag)=0;	Returns a pointer to the connection object from a heterogeneous stateless connection pool; `UString` support.

Parameter	Description
userName	The database username.
password	The database password.
tag	The user defined tag associated with the connection. During the call, the pool is first searched based on the tag provided. If a connection with the specified tag exists it is returned; otherwise a new connection is created and returned.

getIncrConnections()

Returns the number of incremental connections in the connection pool. This call is useful only in cases of homogeneous connection pools.

Syntax

unsigned int getIncrConnections() const=0;

getMaxConnections()

Returns the maximum number of connections in the connection pool.

Syntax

unsigned int getMaxConnections() const=0;

getMinConnections()

Returns the minimum number of connections in the connection pool.

Syntax

unsigned int getMinConnections() const=0;

getOpenConnections()

Returns the number of open connections in the connection pool.

Syntax

unsigned int getOpenConnections() const=0;

getPoolName()

Returns the name of the connection pool.

Syntax

string getPoolName() const=0;

getProxyConnection()

Returns a proxy connection from a connection pool.

Syntax	Description
Connection *getProxyConnection( const string &name, string roles[], unsigned int numRoles, const string& tag="", Connection::ProxyType proxyType=Connection::PROXY_DEFAULT)=0;	Get a proxy connection with role specifications from a connection pool; support for roles and `string` support.
Connection* getProxyConnection( const UString &name, string roles[], unsigned int numRoles, const UString &tag, Connection::ProxyType proxyType = Connection::PROXY_DEFAULT);	Get a proxy connection with role specifications from a connection pool; support for roles and `UString` support.
Connection *getProxyConnection( const string &name, const string& tag="", Connection::ProxyType proxyType=Connection::PROXY_DEFAULT)=0;	Get a proxy connection without role specifications from a connection pool; `string` support.
Connection* getProxyConnection( const UString &name, const UString &tag, Connection::ProxyType proxyType = Connection::PROXY_DEFAULT)	Get a proxy connection without role specifications from a connection pool; `UString` support.

Parameter	Description
name	The username.
roles	The roles to activate on the database server.
numRoles	The number of roles to activate on the database server.
tag	The user defined tag associated with the connection. During the execution of this call, the pool is first searched based on the tag provided. If a connection with the specified tag exists it is returned; otherwise, a new connection is created and returned.
proxyType	The type of proxy authentication to perform; `ProxyType` is defined in Table 12-11.

getStmtCacheSize()

Retrieves the size of the statement cache.

Syntax

unsigned int getStmtCacheSize() const=0;

getTimeOut()

Returns the timeout period of a connection in the connection pool.

Syntax

unsigned int getTimeOut() const=0;

releaseConnection()

Releases the connection back to the pool with an optional tag.

Syntax	Description
void releaseConnection( Connection *connection, const string& tag="");	Support for `string` tag.
void releaseConnection( Connection *connection, const UString &tag);	Support for `UString` tag.

Parameter	Description
connection	The connection to be released.
tag	The user defined tag associated with the connection. The default of this parameter is `""`, which untags the connection.

setBusyOption()

Specifies the behavior of the stateless connection pool when all the connections in the pool are busy, and when the number of connections have reached maximum.

Syntax

void setBusyOption( 
   BusyOption busyOption)=0;

Parameter	Description
busyOption	Valid values are defined in BusyOption in Table 12-40.

Caution:

When busyOption is set to FORCEGET, an attempt can be made to create more connections than can be supported. In such cases, a request for new connections will return an error that will be propagated to the pool user:

ORA 00018 -- Maximum number of sessions exceeded

setPoolSize()

Sets the maximum, minimum, and incremental number of pooled connections for the connection pool.

Syntax

void setPoolSize( 
   unsigned int maxConn=1,
   unsigned int minConn=0,
   unsigned int incrConn=1)=0;

Parameter	Description
maxConn	The maximum number of connections in the connection pool.
minConn	The minimum number of connections, in homogeneous pools only.
incrConn	The incremental number of connections, in homogeneous pools only.

setTimeOut()

Sets the timeout period of a connection in the connection pool. OCCI will terminate any connections related to this connection pool that have been idle for longe4r than the timeout period specified.

Syntax

void setTimeOut( 
   unsigned int connTimeOut=0)=0;

Parameter	Description
connTimeOut	The timeout period, given in seconds.

setStmtCacheSize()

Enables or disables statement caching. A nonzero value will enable statement caching, with a cache of specified size. A zero value will disable caching.

If the user changes the cache size of individual connections and subsequently returns the connection back to the pool with a tag, the cache size does not revert to the one set for the pool. If the connection is untagged, the cache size is reset to equal the cache size specified for the pool.

Syntax

void setStmtCacheSize(
   unsigned int cacheSize)=0;

Parameter	Description
cacheSize	The size of the statement cache

terminateConnection()

Closes the connection and remove it from the pool.

Syntax

void terminateConnection( 
   Connection *connection)=0;

Parameter	Description
connection	The connection to be terminated