001 /**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements. See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership. The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License. You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019 package org.apache.hadoop.lib.service;
020
021 import org.apache.hadoop.classification.InterfaceAudience;
022
023 import java.util.Map;
024
025 @InterfaceAudience.Private
026 public interface Instrumentation {
027
028 public interface Cron {
029
030 public Cron start();
031
032 public Cron stop();
033 }
034
035 public interface Variable<T> {
036
037 T getValue();
038 }
039
040 public Cron createCron();
041
042 public void incr(String group, String name, long count);
043
044 public void addCron(String group, String name, Cron cron);
045
046 public void addVariable(String group, String name, Variable<?> variable);
047
048 //sampling happens once a second
049 public void addSampler(String group, String name, int samplingSize, Variable<Long> variable);
050
051 public Map<String, Map<String, ?>> getSnapshot();
052
053 }