| 1 | /* |
| 2 | * Copyright 2006-2007 the original author or authors. |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package org.springframework.batch.retry.interceptor; |
| 18 | |
| 19 | import org.aopalliance.intercept.MethodInterceptor; |
| 20 | import org.aopalliance.intercept.MethodInvocation; |
| 21 | import org.apache.commons.logging.Log; |
| 22 | import org.apache.commons.logging.LogFactory; |
| 23 | import org.springframework.batch.item.ItemKeyGenerator; |
| 24 | import org.springframework.batch.item.ItemRecoverer; |
| 25 | import org.springframework.batch.item.NewItemIdentifier; |
| 26 | import org.springframework.batch.retry.ExhaustedRetryException; |
| 27 | import org.springframework.batch.retry.RecoveryCallback; |
| 28 | import org.springframework.batch.retry.RetryCallback; |
| 29 | import org.springframework.batch.retry.RetryContext; |
| 30 | import org.springframework.batch.retry.RetryOperations; |
| 31 | import org.springframework.batch.retry.RetryPolicy; |
| 32 | import org.springframework.batch.retry.callback.RecoveryRetryCallback; |
| 33 | import org.springframework.batch.retry.policy.NeverRetryPolicy; |
| 34 | import org.springframework.batch.retry.policy.RecoveryCallbackRetryPolicy; |
| 35 | import org.springframework.batch.retry.support.RetryTemplate; |
| 36 | import org.springframework.util.Assert; |
| 37 | import org.springframework.util.ObjectUtils; |
| 38 | |
| 39 | /** |
| 40 | * A {@link MethodInterceptor} that can be used to automatically retry calls to |
| 41 | * a method on a service if it fails. The argument to the service method is |
| 42 | * treated as an item to be remembered in case the call fails. So the retry |
| 43 | * operation is stateful, and the item that failed is tracked by its unique key |
| 44 | * (via {@link ItemKeyGenerator}) until the retry is exhausted, at which point |
| 45 | * the {@link ItemRecoverer} is called.<br/> |
| 46 | * |
| 47 | * The main use case for this is where the service is transactional, via a |
| 48 | * transaction interceptor on the interceptor chain. In this case the retry (and |
| 49 | * recovery on exhausted) always happens in a new transaction.<br/> |
| 50 | * |
| 51 | * The injected {@link RetryOperations} is used to control the number of |
| 52 | * retries. By default it will retry a fixed number of times, according to the |
| 53 | * defaults in {@link RetryTemplate}.<br/> |
| 54 | * |
| 55 | * @author Dave Syer |
| 56 | */ |
| 57 | public class StatefulRetryOperationsInterceptor implements MethodInterceptor { |
| 58 | |
| 59 | private transient Log logger = LogFactory.getLog(getClass()); |
| 60 | |
| 61 | private ItemKeyGenerator keyGenerator; |
| 62 | |
| 63 | private ItemRecoverer recoverer; |
| 64 | |
| 65 | private NewItemIdentifier newItemIdentifier; |
| 66 | |
| 67 | private final RetryTemplate retryTemplate = new RetryTemplate(); |
| 68 | |
| 69 | /** |
| 70 | * |
| 71 | */ |
| 72 | public StatefulRetryOperationsInterceptor() { |
| 73 | super(); |
| 74 | retryTemplate.setRetryPolicy(new RecoveryCallbackRetryPolicy(new NeverRetryPolicy())); |
| 75 | } |
| 76 | |
| 77 | /** |
| 78 | * Public setter for the {@link ItemRecoverer} to use if the retry is |
| 79 | * exhausted. The recoverer should be able to return an object of the same |
| 80 | * type as the target object because its return value will be used to return |
| 81 | * to the caller in the case of a recovery.<br/> |
| 82 | * |
| 83 | * If no recoverer is set then an exhausted retry will result in an |
| 84 | * {@link ExhaustedRetryException}. |
| 85 | * |
| 86 | * @param recoverer the {@link ItemRecoverer} to set |
| 87 | */ |
| 88 | public void setRecoverer(ItemRecoverer recoverer) { |
| 89 | this.recoverer = recoverer; |
| 90 | } |
| 91 | |
| 92 | public void setKeyGenerator(ItemKeyGenerator keyGenerator) { |
| 93 | this.keyGenerator = keyGenerator; |
| 94 | } |
| 95 | |
| 96 | /** |
| 97 | * Public setter for the retryPolicy. The value provided should be a normal |
| 98 | * stateless policy, which is wrapped into a stateful policy inside this |
| 99 | * method. |
| 100 | * @param retryPolicy the retryPolicy to set |
| 101 | */ |
| 102 | public void setRetryPolicy(RetryPolicy retryPolicy) { |
| 103 | retryTemplate.setRetryPolicy(new RecoveryCallbackRetryPolicy(retryPolicy)); |
| 104 | } |
| 105 | |
| 106 | /** |
| 107 | * Public setter for the {@link NewItemIdentifier}. Only set this if the |
| 108 | * arguments to the intercepted method can be inspected to find out if they |
| 109 | * have never been processed before. |
| 110 | * @param newItemIdentifier the {@link NewItemIdentifier} to set |
| 111 | */ |
| 112 | public void setNewItemIdentifier(NewItemIdentifier newItemIdentifier) { |
| 113 | this.newItemIdentifier = newItemIdentifier; |
| 114 | } |
| 115 | |
| 116 | /** |
| 117 | * Wrap the method invocation in a stateful retry with the policy and other |
| 118 | * helpers provided. If there is a failure the exception will generally be |
| 119 | * re-thrown. The only time it is not re-thrown is when retry is exhausted |
| 120 | * and the recovery path is taken (though the {@link ItemRecoverer} provided |
| 121 | * if there is one). In that case the value returned from the method |
| 122 | * invocation will be the value returned by the recoverer (so the return |
| 123 | * type for that should be the same as the intercepted method). |
| 124 | * |
| 125 | * @see org.aopalliance.intercept.MethodInterceptor#invoke(org.aopalliance.intercept.MethodInvocation) |
| 126 | * @see ItemRecoverer#recover(Object, Throwable) |
| 127 | * |
| 128 | * @throws ExhaustedRetryException if the retry is exhausted and no |
| 129 | * {@link ItemRecoverer} is provided. |
| 130 | */ |
| 131 | public Object invoke(final MethodInvocation invocation) throws Throwable { |
| 132 | |
| 133 | logger.debug("Executing proxied method in stateful retry: " + invocation.getStaticPart() + "(" |
| 134 | + ObjectUtils.getIdentityHexString(invocation) + ")"); |
| 135 | |
| 136 | Object[] args = invocation.getArguments(); |
| 137 | Assert.state(args.length > 0, "Stateful retry applied to method that takes no arguments: " |
| 138 | + invocation.getStaticPart()); |
| 139 | Object arg = args; |
| 140 | if (args.length == 1) { |
| 141 | arg = args[0]; |
| 142 | } |
| 143 | final Object item = arg; |
| 144 | |
| 145 | RecoveryRetryCallback callback = new RecoveryRetryCallback(item, new MethodInvocationRetryCallback(invocation), |
| 146 | keyGenerator != null ? keyGenerator.getKey(item) : item); |
| 147 | callback.setRecoveryCallback(new ItemRecovererCallback(item, recoverer)); |
| 148 | if (newItemIdentifier != null) { |
| 149 | callback.setForceRefresh(newItemIdentifier.isNew(item)); |
| 150 | } |
| 151 | |
| 152 | Object result = retryTemplate.execute(callback); |
| 153 | |
| 154 | logger.debug("Exiting proxied method in stateful retry with result: (" + result + ")"); |
| 155 | |
| 156 | return result; |
| 157 | |
| 158 | } |
| 159 | |
| 160 | /** |
| 161 | * @author Dave Syer |
| 162 | * |
| 163 | */ |
| 164 | private static final class MethodInvocationRetryCallback implements RetryCallback { |
| 165 | /** |
| 166 | * |
| 167 | */ |
| 168 | private final MethodInvocation invocation; |
| 169 | |
| 170 | /** |
| 171 | * @param invocation |
| 172 | */ |
| 173 | private MethodInvocationRetryCallback(MethodInvocation invocation) { |
| 174 | this.invocation = invocation; |
| 175 | } |
| 176 | |
| 177 | public Object doWithRetry(RetryContext context) throws Throwable { |
| 178 | return invocation.proceed(); |
| 179 | } |
| 180 | } |
| 181 | |
| 182 | /** |
| 183 | * @author Dave Syer |
| 184 | * |
| 185 | */ |
| 186 | private static final class ItemRecovererCallback implements RecoveryCallback { |
| 187 | |
| 188 | private final Object item; |
| 189 | |
| 190 | private final ItemRecoverer recoverer; |
| 191 | |
| 192 | /** |
| 193 | * @param item the item that failed. |
| 194 | */ |
| 195 | private ItemRecovererCallback(Object item, ItemRecoverer recoverer) { |
| 196 | this.item = item; |
| 197 | this.recoverer = recoverer; |
| 198 | } |
| 199 | |
| 200 | public Object recover(RetryContext context) { |
| 201 | if (recoverer != null) { |
| 202 | return recoverer.recover(item, context.getLastThrowable()); |
| 203 | } |
| 204 | throw new ExhaustedRetryException("Retry was exhausted but there was no recovery path."); |
| 205 | } |
| 206 | |
| 207 | } |
| 208 | |
| 209 | } |