Copyright 2018 Netflix, Inc.
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.
/**
 * Copyright 2018 Netflix, Inc.
 *
 * 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 com.netflix.concurrency.limits;

import java.util.function.Supplier;

Simple abstraction for tracking metrics in the limiters.
/**
 * Simple abstraction for tracking metrics in the limiters.
 * 
 */
public interface MetricRegistry {
    
Listener to receive samples for a distribution
/**
     * Listener to receive samples for a distribution
     */
    interface SampleListener {
        void addSample(Number value);
    }

    interface Counter {
        void increment();
    }

    
Deprecated:
Use distribution(String, String...)/**
     * @deprecated Use {@link #distribution(String, String...)}
     */
    @Deprecated
    default SampleListener registerDistribution(String id, String... tagNameValuePairs) {
        throw new UnsupportedOperationException("registerDistribution is deprecated");
    }

    
Register a sample distribution. Samples are added to the distribution via the returned SampleListener. Will reuse an existing SampleListener if the distribution already exists. 
Params:
id – 
tagNameValuePairs – Pairs of tag name and tag value.  Number of parameters must be a multiple of 2.
Returns:
SampleListener for the caller to add samples/**
     * Register a sample distribution.  Samples are added to the distribution via the returned
     * {@link SampleListener}.  Will reuse an existing {@link SampleListener} if the distribution already
     * exists.
     *
     * @param id
     * @param tagNameValuePairs Pairs of tag name and tag value.  Number of parameters must be a multiple of 2.
     * @return SampleListener for the caller to add samples
     */
    default SampleListener distribution(String id, String... tagNameValuePairs) {
        return registerDistribution(id, tagNameValuePairs);
    }

    
Deprecated:
Use gauge(String, Supplier<Number>, String...)/**
     * @deprecated Use {@link #gauge(String, Supplier, String...)}
     */
    @Deprecated
    default void registerGauge(String id, Supplier<Number> supplier, String... tagNameValuePairs) {
        throw new UnsupportedOperationException("registerDistribution is deprecated");
    }

    
Register a gauge using the provided supplier.  The supplier will be polled whenever the guage
value is flushed by the registry.
Params:
id – 
tagNameValuePairs – Pairs of tag name and tag value.  Number of parameters must be a multiple of 2.
supplier – /**
     * Register a gauge using the provided supplier.  The supplier will be polled whenever the guage
     * value is flushed by the registry.
     *
     * @param id
     * @param tagNameValuePairs Pairs of tag name and tag value.  Number of parameters must be a multiple of 2.
     * @param supplier
     */
    default void gauge(String id, Supplier<Number> supplier, String... tagNameValuePairs) {
        registerGauge(id, supplier, tagNameValuePairs);
    };

    
Create a counter that will be increment when an event occurs.  Counters normally translate in an action
per second metric.
Params:
id – 
tagNameValuePairs – /**
     * Create a counter that will be increment when an event occurs.  Counters normally translate in an action
     * per second metric.
     *
     * @param id
     * @param tagNameValuePairs
     */
    default Counter counter(String id, String... tagNameValuePairs) {
        return () -> {};
    }

    
Deprecated:
Call MetricRegistry#registerGauge/**
     * @deprecated Call MetricRegistry#registerGauge
     */
    @Deprecated
    default void registerGuage(String id, Supplier<Number> supplier, String... tagNameValuePairs) {
        gauge(id, supplier, tagNameValuePairs);
    }
}