code: /*
   * Copyright © 2014-2017 EntIT Software LLC, a Micro Focus company (L.P.)
   *
   * 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 io.cloudslang.worker.management.services;
  
  import org.apache.commons.lang.Validate;
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  
  /**
   * Date: 6/10/13
   *
   */
  public class RetryTemplate {
  	private final Logger logger = LogManager.getLogger(getClass());
  
  	public final static int INFINITELY = -1;
  
  	public interface RetryCallback{
  		void tryOnce();
  	}
  
  	public void retry(int maxRetries, long sleepBetweenRetries, RetryCallback callback){
  		Validate.notNull(callback, "Callback is null");
  
  		boolean infinity = (maxRetries == INFINITELY);
  		for (int i=0; infinity || i<maxRetries-1; i++) {
  			try {
  				callback.tryOnce();
  				return;
  			} catch (Exception ex) {
  				logger.error("Try #" + (i+1) + " failed on: ", ex);
  				if (sleepBetweenRetries > 0) try {
  						Thread.sleep(sleepBetweenRetries);
  				} catch (InterruptedException iex) {/* do nothing*/}
  			}
  		}
  		callback.tryOnce();
  	}
  }
  