/**
* This function returns the appropriate connection from the pool. When there are
* multiple connections created from the same data source, the last opened connection
* will be returned when $new is set to "FALSE."
*
* @access public
* @param mixed $config the data source configurations
* @param boolean $new whether to create a new connection
* @return DB_Connection_Driver the appropriate connection
* @throws Throwable_Database_Exception indicates that no new connections
* can be added
*/
public function get_connection($config = 'default', $new = FALSE)
{
$data_source = DB_DataSource::instance($config);
if (isset($this->pool[$data_source->id]) and !empty($this->pool[$data_source->id])) {
if ($new) {
foreach ($this->pool[$data_source->id] as $connection) {
if (!$connection->is_connected()) {
$connection->open();
return $connection;
}
}
} else {
$connection = end($this->pool[$data_source->id]);
do {
if ($connection->is_connected()) {
reset($this->pool[$data_source->id]);
return $connection;
}
} while ($connection = prev($this->pool[$data_source->id]));
$connection = end($this->pool[$data_source->id]);
reset($this->pool[$data_source->id]);
$connection->open();
return $connection;
}
}
if ($this->count() >= $this->settings['max_size']) {
throw new Throwable_Database_Exception('Message: Failed to create new connection. Reason: Exceeded maximum number of connections that may be held in the pool.', array(':source' => $data_source, ':new' => $new));
}
$connection = DB_Connection_Driver::factory($data_source);
$connection->open();
$connection_id = $connection->__hashCode();
$this->pool[$data_source->id][$connection_id] = $connection;
$this->lookup[$connection_id] = $data_source->id;
return $connection;
}
