Zookeeper::exists

(PECL zookeeper >= 0.1.0)

Zookeeper::exists — Checks the existence of a node in zookeeper synchronously

说明

public Zookeeper::exists(string $path, callable $watcher_cb = null): array

参数

path

The name of the node. Expressed as a file name with slashes separating ancestors of the node.

watcher_cb

if nonzero, a watch will be set at the server to notify the client if the node changes. The watch will be set even if the node does not

返回值

Returns the value of stat for the path if the given node exists, otherwise false.

错误／异常

This method emits PHP error/warning when parameters count or types are wrong or fail to check the existence of a node.

警告

Since version 0.3.0, this method emits ZookeeperException and it's derivatives.

范例

示例 #1 Zookeeper::exists() example

Check the existence of a node.

<?php
$zookeeper = new Zookeeper('locahost:2181');
$path = '/path/to/node';
$r = $zookeeper->exists($path);
if ($r)
  echo 'EXISTS';
else
  echo 'N/A or ERR';
?>

以上例程会输出：

EXISTS

参见