MetricTag.java

/*
 * Copyright 2010-2014 Ning, Inc.
 *
 * Ning 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.killbill.commons.metrics;

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

import static java.lang.annotation.ElementType.PARAMETER;

/**
 * This annotation can be used to add tags to your resource metrics based on the value of parameters
 * passed into the resource action.
 * <code>
 *     @TimedResource
 *     public Response create(@MetricTag(tag = "type") String type)
 *
 *     @TimedResource
 *     public Response create(@MetricTag(tag = "type", property="paymentType") Payment type)
 * </code>
 *
 * @see TimedResource
 */
@Target(PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
public @interface MetricTag {
    /**
     * Name of the tag.
     */
    String tag();

    /**
     * Optional property name from which the value of tag will be extracted
     */
    String property() default "";
}