core/src/main/java/org/apache/accumulo/core/util/MonitorUtil.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.accumulo.core.util;

import static java.nio.charset.StandardCharsets.UTF_8;

import org.apache.accumulo.core.Constants;
import org.apache.accumulo.core.clientImpl.ClientContext;
import org.apache.accumulo.fate.zookeeper.ZooReader;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.KeeperException.NoNodeException;

import com.google.common.annotations.VisibleForTesting;

public class MonitorUtil {

  public static String getLocation(ClientContext context)
      throws KeeperException, InterruptedException {
    return getLocation(
        new ZooReader(context.getZooKeepers(), context.getZooKeepersSessionTimeOut()), context);
  }

  @VisibleForTesting
  static String getLocation(ZooReader zr, ClientContext context)
      throws KeeperException, InterruptedException {
    try {
      byte[] loc = zr.getData(context.getZooKeeperRoot() + Constants.ZMONITOR_HTTP_ADDR);
      return loc == null ? null : new String(loc, UTF_8);
    } catch (NoNodeException e) {
      // If there's no node advertising the monitor, there's no monitor.
      return null;
    }
  }
}