* $db = ezcDbFactory::create( $dbparams );
* ezcDbInstance::set( $db );
*
* // ...
*
* $db = ezcDbInstance::get();
*
*
* More complex example, with two connections, having identifiers (for convenience):
*
* $mydb = ezcDbFactory::create( $mysql_dbparams );
* $pgdb = ezcDbFactory::create( $pgsql_dbparams );
*
* ezcDbInstance::set( $mydb, 'my' );
* ezcDbInstance::set( $pgdb, 'pg' );
* ezcDbInstance::chooseDefault( 'my' );
*
* // ...
*
* $mydb = ezcDbInstance::get( 'my' ); // returns the mysql instance
* $pgdb = ezcDbInstance::get( 'pg' ); // returns the pgsql instance
* $mydb = ezcDbInstance::get(); // returns the mysql instance which is default
*
*
* @package Database
* @version //autogentag//
* @mainclass
*/
class ezcDbInstance
{
/**
* Identifier of the instance that will be returned
* when you call get() without arguments.
*
* @see ezcDbInstance::get()
* @var string
*/
static private $DefaultInstanceIdentifier = false;
/**
* Holds the database instances.
*
* Example:
*
* array( 'mysql1' => [object],
* 'mysql2' => [object],
* 'oracle' => [object] )
*
*
* @var array(string=>ezcDbHandler)
*/
static private $Instances = array();
/**
* Returns the database instance $identifier.
*
* If $identifier is ommited the default database instance
* specified by chooseDefault() is returned.
*
* @throws ezcDbHandlerNotFoundException if the specified instance is not found.
* @param string $identifier
* @return ezcDbHandler
*/
public static function get( $identifier = false )
{
if ( $identifier === false && self::$DefaultInstanceIdentifier )
{
$identifier = self::$DefaultInstanceIdentifier;
}
if ( !isset( self::$Instances[$identifier] ) )
{
// The DatabaseInstanceFetchConfig callback should return an
// ezcDbHandler object which will then be set as instance.
$ret = ezcBaseInit::fetchConfig( 'ezcInitDatabaseInstance', $identifier );
if ( $ret === null )
{
throw new ezcDbHandlerNotFoundException( $identifier );
}
else
{
self::set( $ret, $identifier );
}
}
return self::$Instances[$identifier];
}
/**
* Returns the identifiers of the registered database instances.
*
* @return array(string)
*/
public static function getIdentifiers()
{
return array_keys( self::$Instances );
}
/**
* Adds the database handler $db to the list of known instances.
*
* If $identifier is specified the database instance can be
* retrieved later using the same identifier.
*
* @param ezcDbHandler $db
* @param string $identifier the identifier of the database handler
* @return void
*/
public static function set( ezcDbHandler $db, $identifier = false )
{
self::$Instances[$identifier] = $db;
}
/**
* Sets the database $identifier as default database instance.
*
* To retrieve the default database instance
* call get() with no parameters..
*
* @see ezcDbInstance::get().
* @param string $identifier
* @return void
*/
public static function chooseDefault( $identifier )
{
self::$DefaultInstanceIdentifier = $identifier;
}
/**
* Resets the default instance holder.
*
* @return void
*/
public static function resetDefault()
{
self::$DefaultInstanceIdentifier = false;
}
/**
* Resets this object to its initial state.
*
* The list of instances will be emptied and
* {@link resetDefault()} will be called.
*
* @return void
*/
public static function reset()
{
self::$Instances = array();
self::resetDefault();
}
}
?>