/**
* 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.hadoop.hive.common.metrics.common;
/**
* Generic Metics interface.
*/
public interface Metrics {
/**
* Deinitializes the Metrics system.
*/
public void close() throws Exception;
/**
*
* @param name starts a scope of a given name. Scopes is stored as thread-local variable.
*/
public void startStoredScope(String name);
/**
* Closes the stored scope of a given name.
* Note that this must be called on the same thread as where the scope was started.
* @param name
*/
public void endStoredScope(String name);
/**
* Create scope with given name and returns it.
* @param name
* @return
*/
public MetricsScope createScope(String name);
/**
* Close the given scope.
* @param scope
*/
public void endScope(MetricsScope scope);
//Counter-related methods
/**
* Increments a counter of the given name by 1.
* @param name
* @return
*/
public Long incrementCounter(String name);
/**
* Increments a counter of the given name by "increment"
* @param name
* @param increment
* @return
*/
public Long incrementCounter(String name, long increment);
/**
* Decrements a counter of the given name by 1.
* @param name
* @return
*/
public Long decrementCounter(String name);
/**
* Decrements a counter of the given name by "decrement"
* @param name
* @param decrement
* @return
*/
public Long decrementCounter(String name, long decrement);
/**
* Adds a metrics-gauge to track variable. For example, number of open database connections.
* @param name name of gauge
* @param variable variable to track.
*/
public void addGauge(String name, final MetricsVariable variable);
/**
* Add a ratio metric to track the correlation between two variables
* @param name name of the ratio gauge
* @param numerator numerator of the ratio
* @param denominator denominator of the ratio
*/
public void addRatio(String name, MetricsVariable<Integer> numerator,
MetricsVariable<Integer> denominator);
/**
* Mark an event occurance for a meter. Meters measure the rate of an event and track
* 1/5/15 minute moving averages
* @param name name of the meter
*/
public void markMeter(String name);
}