Java tutorial
/** * Copyright 2013 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 c3.ops.priam.utils; import org.apache.commons.lang3.exception.ExceptionUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.util.concurrent.Callable; import java.util.concurrent.CancellationException; public abstract class RetryableCallable<T> implements Callable<T> { public static final int DEFAULT_NUMBER_OF_RETRIES = 15; public static final long DEFAULT_WAIT_TIME = 100; private static final Logger logger = LoggerFactory.getLogger(RetryableCallable.class); private int retrys; private long waitTime; public RetryableCallable() { this(DEFAULT_NUMBER_OF_RETRIES, DEFAULT_WAIT_TIME); } public RetryableCallable(int retrys, long waitTime) { set(retrys, waitTime); } public void set(int retrys, long waitTime) { this.retrys = retrys; this.waitTime = waitTime; } public abstract T retriableCall() throws Exception; public T call() throws Exception { int retry = 0; int logCounter = 0; while (true) { try { return retriableCall(); } catch (CancellationException e) { throw e; } catch (Exception e) { retry++; if (retry == retrys) { throw e; } logger.error(String.format("Retry #%d for: %s", retry, e.getMessage())); if (++logCounter == 1) logger.error("Exception --> " + ExceptionUtils.getStackTrace(e)); Thread.sleep(waitTime); } finally { forEachExecution(); } } } public void forEachExecution() { // do nothing by default. } }