(PECL zookeeper >= 0.1.0)
Zookeeper::exists — Checks the existence of a node in zookeeper synchronously
pathThe name of the node. Expressed as a file name with slashes separating ancestors of the node.
watcher_cbif 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
Returns true/false on success, and false on failure.
This method emits PHP error/warning when parameters count or types are wrong or fail to check the existence of a node.
Since version 0.3.0, this method emits ZookeeperException and it's derivatives.
Example #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