SunshinePHP 2019 CFP Started

Zookeeper::exists

(PECL zookeeper >= 0.1.0)

Zookeeper::existsChecks the existence of a node in zookeeper synchronously

说明

public bool Zookeeper::exists ( string $path [, callable $watcher_cb = NULL ] )

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 true/false on success, and false on failure.

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

参见

  • Zookeeper::get() - Gets the data associated with a node synchronously
  • ZookeeperException
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