kamon.annotation.Time Maven / Gradle / Ivy

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/*
 * =========================================================================================
 * Copyright © 2013-2015 the kamon project 
 *
 * Licensed 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 kamon.annotation;


import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;


/**
 * A marker annotation to define a method as a timed.
 * 
 * 

 * Given a method like this:
 * 

 *     {@literal @}Timed(name = "coolName", tags="""${{'my-cool-tag':'my-cool-value'}}""")
 *     public String coolName(String name) {
 *         return "Hello " + name;
 *     }
 * 
 * 
 * 
 * A histogram for the defining method with the name {@code coolName} will be created and each time the
 * {@code #coolName(String)} method is invoked, the latency of execution will be recorded.
 */
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface Time {
    /**
     * @return The histogram's name.
     */
    String name();

    /**
     * Tags are a way of adding dimensions to metrics,
     * these are constructed using EL syntax e.g. """${{'algorithm':'1','env':'production'}}"""
     *
     * @return the tags associated to the histogram
     */
    String tags() default "";
}