本文整理汇总了Java中org.apache.hadoop.hbase.EmptyWatcher类的典型用法代码示例。如果您正苦于以下问题：Java EmptyWatcher类的具体用法？Java EmptyWatcher怎么用？Java EmptyWatcher使用的例子？那么恭喜您, 这里精选的类代码示例或许可以为您提供帮助。
EmptyWatcher类属于org.apache.hadoop.hbase包，在下文中一共展示了EmptyWatcher类的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Java代码示例。
示例1: waitForBaseZNode
import org.apache.hadoop.hbase.EmptyWatcher; //导入依赖的package包/类
/**
* Waits for HBase installation's base (parent) znode to become available.
* @throws IOException on ZK errors
*/
public static void waitForBaseZNode(Configuration conf) throws IOException {
LOG.info("Waiting until the base znode is available");
String parentZNode = conf.get(HConstants.ZOOKEEPER_ZNODE_PARENT,
HConstants.DEFAULT_ZOOKEEPER_ZNODE_PARENT);
ZooKeeper zk = new ZooKeeper(ZKConfig.getZKQuorumServersString(conf),
conf.getInt(HConstants.ZK_SESSION_TIMEOUT,
HConstants.DEFAULT_ZK_SESSION_TIMEOUT), EmptyWatcher.instance);
final int maxTimeMs = 10000;
final int maxNumAttempts = maxTimeMs / HConstants.SOCKET_RETRY_WAIT_MS;
KeeperException keeperEx = null;
try {
try {
for (int attempt = 0; attempt < maxNumAttempts; ++attempt) {
try {
if (zk.exists(parentZNode, false) != null) {
LOG.info("Parent znode exists: " + parentZNode);
keeperEx = null;
break;
}
} catch (KeeperException e) {
keeperEx = e;
}
Threads.sleepWithoutInterrupt(HConstants.SOCKET_RETRY_WAIT_MS);
}
} finally {
zk.close();
}
} catch (InterruptedException ex) {
Thread.currentThread().interrupt();
}
if (keeperEx != null) {
throw new IOException(keeperEx);
}
}