| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.hadoop.io.retry; |
| |
| import java.lang.reflect.InvocationHandler; |
| import java.lang.reflect.InvocationTargetException; |
| import java.lang.reflect.Method; |
| import java.util.Collections; |
| import java.util.Map; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.hadoop.util.StringUtils; |
| |
| class RetryInvocationHandler implements InvocationHandler { |
| public static final Log LOG = LogFactory.getLog(RetryInvocationHandler.class); |
| private Object implementation; |
| |
| private RetryPolicy defaultPolicy; |
| private Map<String,RetryPolicy> methodNameToPolicyMap; |
| |
| public RetryInvocationHandler(Object implementation, RetryPolicy retryPolicy) { |
| this.implementation = implementation; |
| this.defaultPolicy = retryPolicy; |
| this.methodNameToPolicyMap = Collections.emptyMap(); |
| } |
| |
| public RetryInvocationHandler(Object implementation, Map<String, RetryPolicy> methodNameToPolicyMap) { |
| this.implementation = implementation; |
| this.defaultPolicy = RetryPolicies.TRY_ONCE_THEN_FAIL; |
| this.methodNameToPolicyMap = methodNameToPolicyMap; |
| } |
| |
| public Object invoke(Object proxy, Method method, Object[] args) |
| throws Throwable { |
| RetryPolicy policy = methodNameToPolicyMap.get(method.getName()); |
| if (policy == null) { |
| policy = defaultPolicy; |
| } |
| |
| int retries = 0; |
| while (true) { |
| try { |
| return invokeMethod(method, args); |
| } catch (Exception e) { |
| if (!policy.shouldRetry(e, retries++)) { |
| LOG.info("Exception while invoking " + method.getName() |
| + " of " + implementation.getClass() + ". Not retrying." |
| + StringUtils.stringifyException(e)); |
| if (!method.getReturnType().equals(Void.TYPE)) { |
| throw e; // non-void methods can't fail without an exception |
| } |
| return null; |
| } |
| LOG.debug("Exception while invoking " + method.getName() |
| + " of " + implementation.getClass() + ". Retrying." |
| + StringUtils.stringifyException(e)); |
| } |
| } |
| } |
| |
| private Object invokeMethod(Method method, Object[] args) throws Throwable { |
| try { |
| if (!method.isAccessible()) { |
| method.setAccessible(true); |
| } |
| return method.invoke(implementation, args); |
| } catch (InvocationTargetException e) { |
| throw e.getCause(); |
| } |
| } |
| |
| } |