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 java.util.Map;
022    
023    public interface Instrumentation {
024    
025      public interface Cron {
026    
027        public Cron start();
028    
029        public Cron stop();
030      }
031    
032      public interface Variable<T> {
033    
034        T getValue();
035      }
036    
037      public Cron createCron();
038    
039      public void incr(String group, String name, long count);
040    
041      public void addCron(String group, String name, Cron cron);
042    
043      public void addVariable(String group, String name, Variable<?> variable);
044    
045      //sampling happens once a second
046      public void addSampler(String group, String name, int samplingSize, Variable<Long> variable);
047    
048      public Map<String, Map<String, ?>> getSnapshot();
049    
050    }