Conventions

In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.

Code words in text are shown as follows: "The org.apache.zookeeper is composed of the interface definition for ZooKeeper watches and various callback handlers of ZooKeeper."

A block of code is set as follows:

public class HelloZooKeeper {
  public static void main(String[] args) throws IOException {
    String hostPort = "localhost:2181";
    String zpath = "/";
    List <String> zooChildren = new ArrayList <String> ();
    ZooKeeper zk = new ZooKeeper(hostPort, 2000, null);
  }
}

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

from kazoo.client import KazooClient
zoo_path = '/MyPath'
zk = KazooClient(hosts='localhost:2181')
zk.start()
zk.ensure_path(zoo_path)

Any command-line input or output is written as follows:

${ZK_HOME}/bin/zkCli.sh –server zk_server:port

New terms and important words are shown in bold. Words that you see on the screen, in menus, or dialog boxes for example, appear in the text like this: "The MBeans tab shows detailed information about ZooKeeper's internal state."