# MongoDB\Driver\Monitoring\SDAMSubscriber::topologyOpening

(mongodb >=1.13.0)

MongoDB\Driver\Monitoring\SDAMSubscriber::topologyOpening — Notification method for opening the topology

### 说明

abstract public MongoDB\Driver\Monitoring\SDAMSubscriber::topologyOpening(MongoDB\Driver\Monitoring\TopologyOpeningEvent `$event`): void

If the subscriber is registered, this method is called when the topology is opened.

> 注意: Due to the driver's connection handling and persistence behavior, this event may not be observed if a MongoDB\Driver\Manager uses a previously persisted » libmongoc client.

### 参数

`event` (MongoDB\Driver\Monitoring\TopologyOpeningEvent)

  An event object encapsulating information about the opened topology.

### 返回值

没有返回值。

### 错误／异常

- Throws MongoDB\Driver\Exception\InvalidArgumentException on argument parsing errors.

### 参见

- MongoDB\Driver\Monitoring\TopologyOpeningEvent
- MongoDB\Driver\Monitoring\addSubscriber() - Registers a monitoring event subscriber globally
- MongoDB\Driver\Manager::addSubscriber() - Registers a monitoring event subscriber with this Manager

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