org.apache.hadoop.metrics2.annotation.Metric Maven / Gradle / Ivy
/**
* 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.metrics2.annotation;
import java.lang.annotation.*;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
/**
* Annotation interface for a single metric used to annotate a field or a method
* in the class.
*/
@InterfaceAudience.Public
@InterfaceStability.Evolving
@Documented
@Target({ElementType.FIELD, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface Metric {
public enum Type {
DEFAULT, COUNTER, GAUGE, TAG
}
/**
* Shorthand for optional name and description
* @return {description} or {name, description}
*/
String[] value() default {};
/**
* @return optional description of the metric
*/
String about() default "";
/**
* @return optional sample name for MutableStat/Rate/Rates
*/
String sampleName() default "Ops";
/**
* @return optional value name for MutableStat/Rate/Rates
*/
String valueName() default "Time";
/**
* @return true to create a metric snapshot even if unchanged.
*/
boolean always() default false;
/**
* @return optional type (counter|gauge) of the metric
*/
Type type() default Type.DEFAULT;
/**
* @return optional roll over interval in secs for MutableQuantiles
*/
int interval() default 10;
}