001/* 002 * Copyright 2002-2014 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.util.backoff; 018 019/** 020 * Provide a {@link BackOffExecution} that indicates the rate at which 021 * an operation should be retried. 022 * 023 * <p>Users of this interface are expected to use it like this: 024 * 025 * <pre class="code"> 026 * BackOffExecution exec = backOff.start(); 027 * 028 * // In the operation recovery/retry loop: 029 * long waitInterval = exec.nextBackOff(); 030 * if (waitInterval == BackOffExecution.STOP) { 031 * // do not retry operation 032 * } 033 * else { 034 * // sleep, e.g. Thread.sleep(waitInterval) 035 * // retry operation 036 * } 037 * }</pre> 038 * 039 * Once the underlying operation has completed successfully, 040 * the execution instance can be simply discarded. 041 * 042 * @author Stephane Nicoll 043 * @since 4.1 044 * @see BackOffExecution 045 */ 046public interface BackOff { 047 048 /** 049 * Start a new back off execution. 050 * @return a fresh {@link BackOffExecution} ready to be used 051 */ 052 BackOffExecution start(); 053 054}