Php/docs/zookeeper.exists
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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 $watcher_cb = null
] ) : array
参数
path- The name of the node. Expressed as a file name with slashes separating ancestors of the node.
watcher_cb- if nonzero, a watch will be set at the server to notify the client if the node changes. The watch will be set even if the node does not
返回值
Returns the value of stat for the path if the given node exists, otherwise false.
错误／异常
This method emits PHP error/warning when parameters count or types are wrong or fail to check the existence of a node.
Caution Since version 0.3.0, this method emits ZookeeperException and it's derivatives.
范例
Example #1 Zookeeper::exists() example
Check the existence of a node.
<?php$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
