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Oracle® C++ Call Interface Programmer's Guide,
11g Release 1 (11.1)

B28390-07
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Environment Class

The Environment class provides an OCCI environment to manage memory and other resources for OCCI objects.

The application can have multiple OCCI environments. Each environment would have its own heap and thread-safety mutexes.

Table 13-17 Enumerated Values Used by Environment Class

Attribute Options
Mode
  • DEFAULT is used for creating an Environment object; it has no thread safety or object support.

  • OBJECT is for creating an Environment object; it uses object features.

  • SHARED is for creating an Environment object.

  • NO_USERCALLBACKS is for creating an Environment object; it does not support user callbacks.

  • THREADED_MUTEXED is a thread safe mode for creating an Environment object, mutexed internally by OCCI.

  • THREADED_UNMUTEXED is a thread safe mode for creating an Environment object; the client is responsible for mutexing.

  • EVENTS supports registration for event notification used in Oracle Streams Advanced Queuing.

  • USE_LDAP supports registration with LDAP.


Table 13-18 Summary of Environment Methods

Method Summary

createConnection()

Establishes a connection to the specified database.

createConnectionPool()

Creates a connection pool.

createEnvironment()

Creates an Environment object.

createStatelessConnectionPool()

Creates a stateless connection pool.

enableSubscription()

Enables subscription notification

disableSubscription()

Disables subscription notification

getCacheMaxSize()

Retrieves the Cache Max heap size.

getCacheOptSize()

Retrieves the cache optimal heap size.

getCacheSortedFlush()

Retrieves the setting of the cache sorting flag.

getClientVersion()

Returns the version of the client library.

getCurrentHeapSize()

Returns the current amount of memory allocated to all objects in the current environment.

getLDAPAdminContext()

Returns the administrative context when using LDAP open notification registration.

getLDAPAuthentication()

Returns the authentication mode when using LDAP open notification registration.

getLDAPHost()

Returns the host on which the LDAP server runs.

getLDAPPort()

Returns the port on which the LDAP server is listening.

getMap()()

Returns the Map for the current environment.

getOCIEnvironment()

Returns the OCI environment associated with the current environment.

 

getXAConnection()

Creates an XA connection to a database.

getXAEnvironment()

Creates an XA Environment object.

releaseXAConnection()

Releases all resources allocated by a getXAConnection() call.

releaseXAEnvironment()

Releases all resources allocated by a getXAEnvironment() call.

setCacheMaxSize()

Specifies the maximum size for the client-side object cache as a percentage of the optimal size.

setCacheOptSize()

Specifies the optimal size for the client-side object cache in bytes.

setCacheSortedFlush()

Specifies whether to sort cache in table order prior to flushing.

setLDAPAdminContext()

Specifies the administrative context for the LDAP client.

setLDAPAuthentication()

Specifies the LDAP authentication mode.

setLDAPHostAndPort()

Specifies the LDAP server host and port.

setLDAPLoginNameAndPassword()

Specifies the login name and password when connecting to an LDAP server.

 

terminateConnection()

Closes the connection pool and free all related resources.

terminateConnectionPool()

Closes the connection pool and free all related resources.

terminateEnvironment()

Destroys the environment.

terminateStatelessConnectionPool()

Closes the stateless connection pool and free all related resources.



createConnection()

This method establishes a connection to the database specified.

Syntax Description
Connection * createConnection(
   const string &userName,
   const string &password,
   const string &connectString="")=0;
Creates a default connection.
Connection * createConnection(
   const UString &userName,
   const UString &password,
   const UString &connectString)=0;
Creates a connection (Unicode support). The client Environment should be initialized in OCCIUTIF16 mode.
Connection * createConnection(
   const string &userName,
   const string &password,
   const string &connectString,
   const string &connectionClass,
   const Connection::Purity &purity)=0;
Creates a connection for database resident connection pooling.
Connection * createConnection(
   const UString &userName,
   const UString &password,
   const UString &connectString,
   const UString &connectionClass
   const Connection::Purity &purity)=0;
Creates a connection for database resident connection pooling (Unicode support). The client Environment should be initialized in OCCIUTIF16 mode.

Parameter Description
userName
The name of the user with which to connect.
password
The password of the user.
connectString
The database to which the connection is made.
purity
The purity of the connection used for database resident connection pooling; either SELF or NEW.
connectionClass
The connection class used for database resident connection pooling.


createConnectionPool()

Creates a connection pool based on the parameters specified.

Syntax Description
ConnectionPool* createConnectionPool(
   const string &poolUserName,
   const string &poolPassword,
   const string &connectString = "",
   unsigned int minConn = 0,
   unsigned int maxConn = 1,
   unsigned int incrConn = 1)=0;
Creates a default connection pool.
ConnectionPool* createConnectionPool(
   const UString &poolUserName,
   const UString &poolPassword,
   const UString &connectString,
   unsigned int minConn = 0,
   unsigned int maxConn = 1,
   unsigned int incrConn = 1)=0;
Creates a connection pool (Unicode support). The client Environment should be initialized in OCCIUTIF16 mode.

Parameter Description
poolUserName
The pool user name.
poolPassword
The pool password.
connectString
The connection string for the server
minConn
The minimum number of connections in the pool. The minimum number of connections are opened by this method. Additional connections are opened only when necessary. Generally, minConn should be set to the number of concurrent statements the application is expected to run.
maxConn
The maximum number of connections in the pool. Valid values are 1 and greater.
incrConn
The increment by which to increase the number of connections to be opened if the current number of connections is less than maxConn. Valid values are 1 and greater.


createEnvironment()

Creates an Environment object. It is created with the specified memory management functions specified in the setMemMgrFunctions() method. If no memory manager functions are specified, then OCCI uses its own default functions. An Environment object must eventually be closed to free all the system resources it has acquired.

If the Mode is specified is either THREADED_MUTEXED or THREADED_UNMUTEXED as defined in Table 13-17, then all three memory management functions must be thread-safe.

Syntax Description
static Environment * createEnvironment(
   Mode mode = DEFAULT,
   void *ctxp = 0,
   void *(*malocfp)(void *ctxp,
                    size_t size) = 0,
   void *(*ralocfp)(void *ctxp, 
                    void *memptr,
                    size_t newsize) = 0,
   void (*mfreefp)(void *ctxp,
                   void *memptr) = 0);
Creates a default environment.
static Environment * createEnvironment(
   const string &charset,
   const string &ncharset,
   Mode mode = DEFAULT,
   void *ctxp = 0,
   void *(*malocfp)(void *ctxp,
                    size_t size) = 0,
   void *(*ralocfp)(void *ctxp, 
                    void *memptr,
                    size_t newsize) = 0,
   void (*mfreefp)(void *ctxp,
                   void *memptr) = 0);
Creates an environment with the specified character set and NCHAR character set ids (Unicode support). The client Environment should be initialized in OCCIUTIF16 mode.

Parameter Description
mode
Values are defined as part of Mode in Table 13-17: DEFAULT, THREADED_MUTEXED, THREADED_UNMUTEXED, OBJECT.
ctxp
Context pointer for user-defined memory management function.
size
The size of the memory allocated by user-defined memory allocation function.
newsize
The new size of the memory to be reallocated.
memptr
the existing memory that needs to be reallocated to new size.
malocfp
User-defined memory allocation function.
ralocfp
User-defined memory reallocation function.
mfreefp
User-defined memory free function.
charset
Character set id that will replace the one specified in NLS_LANG.
ncharset
Character set id that will replace the one specified in NLS_NCHAR.


createStatelessConnectionPool()

Creates a StatelessConnectionPool object with specified pool attributes.

Syntax Description
StatelessConnectionPool* createStatelessConnectionPool(
   const string &poolUserName,
   const string &poolPassword,
   const string connectString="",
   unsigned int maxConn=1,
   unsigned int minConn=0,
   unsigned int incrConn=1,
   StatelessConnectionPool::PoolType
      pType=StatelessConnectionPool::HETEROGENEOUS);
Support for string.
StatelessConnectionPool* createStatelessConnectionPool(
   const UString &poolUserName,
   const UString &poolPassword,
   const UString &connectString,
   unsigned int maxConn = 1,
   unsigned int minConn = 0,
   unsigned int incrConn = 1,
   StatelessConnectionPool::PoolType 
   pType=StatelessConnectionPool::HETEROGENEOUS);
Support for UString.

Parameter Description
poolUserName
The pool user name.
poolPassword
The pool password.
connectString
The connection string for the server.
maxConn
The maximum number of connections that can be opened the pool; additional sessions cannot be open.
minConn
The number of connections initially created in a pool. This parameter is considered only if the PoolType is set to HOMOGENEOUS, as defined in Table 13-40 .
incrConn
The number of connections by which to increment the pool if all open connections are busy, up to a maximum open connections specified by maxConn parameter. This parameter is considered only if the PoolType is set to HOMOGENEOUS, as defined in Table 13-40 .
pType
The PoolType of the connection pool, defined in Table 13-40 .


enableSubscription()

Enables subscription notification.

Syntax

void enableSubscription(
   const aq::Subscription &sub);
Parameter Description
sub
The Subscription.


disableSubscription()

Disables subscription notification.

Syntax

void disableSubscription(
   Subscription &subscr);
Parameter Description
subscr
The Subscription.


getCacheMaxSize()

Retrieves the maximum size of the cache.

Syntax

unsigned int getCacheMaxSize() const;

getCacheOptSize()

Retrieves the Cache optimal heap size.

Syntax

unsigned int getCacheOptSize() const;

getCacheSortedFlush()

Retrieves the current setting of the cache sorting flag; TRUE or FALSE.

Syntax

bool getCacheSortedFlush() const;

getCurrentHeapSize()

Returns the amount of memory currently allocated to all objects in this environment.

Syntax

unsigned int getCurrentHeapSize() const;

getLDAPAdminContext()

Returns the administrative context when using LDAP open notification registration.

Syntax

string getLDAPAdminContext() const;

getLDAPAuthentication()

Returns the authentication mode when using LDAP open notification registration.

Syntax

unsigned int getLDAPAuthentication() const;

getLDAPHost()

Returns the host on which the LDAP server runs.

Syntax

string getLDAPHost() const;
 

getLDAPPort()

Returns the port on which the LDAP server is listening.

Syntax

unsigned int getLDAPPort() const;

getMap()

Returns a pointer to the map for this environment.

Syntax

Map *getMap() const;

getOCIEnvironment()

Returns a pointer to the OCI environment associated with this environment.

Syntax

OCIEnv *getOCIEnvironment() const;

getXAConnection()

Returns a pointer to an OCCI Connection object that corresponds to the one opened by the XA library.

Syntax

Connection* getXAConnection(
   const string &dbname);
Parameter Description
dbname
The database name; same as the optional dbname provided in the Open String (and used in connection to the Resource Manager).


getXAEnvironment()

Returns a pointer to an OCCI Environment object that corresponds to the one opened by the XA library.

Syntax

Environment *getXAEnvironment(
   const string &dbname);
Parameter Description
dbname
The database name; same as the optional dbname provided in the Open String (and used in connection to the Resource Manager).


releaseXAConnection()

Release/deallocate all resources allocated by the getXAConnection() method.

Syntax

void releaseXAConnection(
   Connection* conn);
Parameter Description
conn
The connection returned by the getXAConnection() method.


releaseXAEnvironment()

Release/deallocate all resources allocated by the getXAEnvironment() method.

Syntax

void releaseXAEnvironment(
   Environment* env);
Parameter Description
env
The environment returned by the getXAEnvironment() method.


setCacheMaxSize()

Sets the maximum size for the client-side object cache as a percentage of the optimal size. The default value is 10%.

Syntax

void setCacheMaxSize(
   unsigned int maxSize);
Parameter Description
maxSize
The value of the maximum size, as a percentage.


setCacheOptSize()

Sets the optimal size for the client-side object cache in bytes. The default value is 8MB.

Syntax

void setCacheOptSize(
   unsigned int optSize);
Parameter Description
optSize
The value of the optimal size, in bytes.


setCacheSortedFlush()

Sets the cache flushing protocol. By default, objects in cache are flushed in the order they are modified; flag=FALSE. To improve server-side performance, set flag=TRUE, so that the objects in cache are sorted in table order prior to flushing from client cache.

Syntax

void setCacheSortedFlush(
   bool flag);
Parameter Description
flag
FALSE (default) -- no sorting; TRUE -- sorting in table order


setLDAPAdminContext()

Sets the administrative context of the client. This is usually the root of the Oracle RDBMS LDAP schema in the LDAP server.

Syntax

void setLDAPAdminContext(
   const string &ctx);
Parameter Description
ctx
The client context


setLDAPAuthentication()

Specifies the authentication mode. Currently the only supported value is 0x1: Simple authentication; username/password authentication.

Syntax

void setLDAPAuthentication(
   unsigned int mode);
Parameter Description
mode
The authentication mode


setLDAPHostAndPort()

Specifies the host on which the LDAP server is running, and the port on which it is listening for requests.

Syntax

void setLDAPHostAndPort(
   const string &host,
   unsigned int port);
Parameter Description
host
The host for LDAP
port
The port for LDAP


setLDAPLoginNameAndPassword()

Specifies the login distinguished name and password used when connecting to an LDAP server.

Syntax

void setLDAPLoginNameAndPassword(
   const string &login,
   const &passwd);
Parameter Description
login
The login name
passwd
The login password


terminateConnection()

Closes the connection to the environment, and frees all related system resources.

Syntax

void terminateConnection(
   Connection *connection);
Parameter Description
connection
A pointer to the connection instance to be terminated.


terminateConnectionPool()

Closes the connections in the connection pool, and frees all related system resources.

Syntax

void terminateConnectionPool(
   ConnectionPool *poolPointer);
Parameter Description
poolPointer
A pointer to the connection pool instance to be terminated.


terminateEnvironment()

Closes the environment, and frees all related system resources.

Syntax

void terminateEnvironment(
   Environment *env);
Parameter Description
env
Environment to be closed.


terminateStatelessConnectionPool()

Destroys the specified StatelessConnectionPool.

Syntax

void termimnateStatelessConnectionPool(
   StatelessConnectionPool* poolPointer,
   StatelessConnectionPool::DestroyMode mode=StatelessConnectionPool::DEFAULT);
Parameter Description
poolPointer
The StatelessConnectionPool to be destroyed.
mode DestroyMode as defined Table 13-40: DEFAULT or SPF_FORCE.