001/** 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software 013 * distributed under the License is distributed on an "AS IS" BASIS, 014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015 * See the License for the specific language governing permissions and 016 * limitations under the License. 017 */ 018 019package org.apache.oozie.client.retry; 020 021import java.io.IOException; 022import java.net.ConnectException; 023import java.net.SocketException; 024import java.net.URL; 025 026/** 027 * HTTP connection retryable class. It retries =oozie.connection.retry.count= times for ConnectException. For 028 * SocketException all create connection are retried except =PUT= and =POST=. 029 */ 030public abstract class ConnectionRetriableClient { 031 private final int retryCount; 032 033 public ConnectionRetriableClient(int retryCount) { 034 this.retryCount = retryCount; 035 } 036 037 public Object execute(URL url, String method) throws IOException { 038 int numTries = 0; 039 boolean stopRetry = false; 040 Exception cliException = null; 041 042 while (numTries < retryCount && !stopRetry) { 043 try { 044 return doExecute(url, method); 045 } 046 catch (ConnectException e) { 047 sleep(e, numTries++); 048 cliException = e; 049 } 050 catch (SocketException e) { 051 if (method.equals("POST") || method.equals("PUT")) { 052 stopRetry = true; 053 } 054 else { 055 sleep(e, numTries++); 056 } 057 cliException = e; 058 } 059 catch (Exception e) { 060 stopRetry = true; 061 cliException = e; 062 numTries++; 063 // No retry for other exceptions 064 } 065 } 066 throw new IOException("Error while connecting Oozie server. No of retries = " + numTries + ". Exception = " 067 + cliException.getMessage(), cliException); 068 } 069 070 private void sleep(Exception e, int numTries) { 071 try { 072 long wait = getWaitTimeExp(numTries); 073 System.err.println("Connection exception has occurred [ " + e.getClass().getName() + " " + e.getMessage() 074 + " ]. Trying after " + wait / 1000 + " sec." + " Retry count = " + (numTries + 1)); 075 Thread.sleep(wait); 076 } 077 catch (InterruptedException e1) { 078 // Ignore InterruptedException 079 } 080 } 081 082 /* 083 * Returns the next wait interval, in milliseconds, using an exponential backoff algorithm. 084 */ 085 private long getWaitTimeExp(int retryCount) { 086 long waitTime = ((long) Math.pow(2, retryCount) * 1000L); 087 return waitTime; 088 } 089 090 public abstract Object doExecute(URL url, String method) throws Exception; 091 092}