com.couchbase.client.core.retry.reactor.Jitter Maven / Gradle / Ivy

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The official Couchbase JVM Core IO Library

There is a newer version: 2.7.0

/*
 * Copyright (c) 2017 Pivotal Software Inc, All Rights Reserved.
 *
 * 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.couchbase.client.core.retry.reactor;

import java.time.Duration;
import java.util.function.Function;

/**
 * Jitter function that is applied to the backoff delay.
 *
 */
public interface Jitter extends Function {

	Jitter NO_JITTER = new Jitter() {
		@Override
		public Duration apply(BackoffDelay delay) {
			return delay.delay();
		}

		@Override
		public String toString() {
			return "Jitter{NONE}";
		}
	};

	Jitter RANDOM_JITTER = new RandomJitter(0.5);

	/**
	 * Jitter function that is a no-op.
	 * @return Jitter function that does not apply any jitter
	 */
	static Jitter noJitter() {
		return NO_JITTER;
	}

	/**
	 * Jitter function that applies a random jitter with a factor of 0.5, generating a
	 * backoff between {@code [d - d*0.5; d + d*0.5]} (but still within the limits of
	 * [{@link BackoffDelay#minDelay()}; {@link BackoffDelay#maxDelay()}].
	 * @return Jitter function to randomize backoff delay
	 */
	static Jitter random() {
		return RANDOM_JITTER;
	}

	/**
	 * Jitter function that applies a random jitter with a provided [0; 1] factor (default 0.5),
	 * generating a backoff between {@code [d - d*factor; d + d*factor]} (but still within
	 * the limits of [{@link BackoffDelay#minDelay()}; {@link BackoffDelay#maxDelay()}].
	 * @return Jitter function to randomize backoff delay
	 */
	static Jitter random(double randomFactor) {
		return new RandomJitter(randomFactor);
	}
}