| 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.repeat.interceptor; |
| 18 | |
| 19 | import org.aopalliance.intercept.MethodInterceptor; |
| 20 | import org.aopalliance.intercept.MethodInvocation; |
| 21 | import org.springframework.aop.ProxyMethodInvocation; |
| 22 | import org.springframework.batch.repeat.ExitStatus; |
| 23 | import org.springframework.batch.repeat.RepeatCallback; |
| 24 | import org.springframework.batch.repeat.RepeatContext; |
| 25 | import org.springframework.batch.repeat.RepeatException; |
| 26 | import org.springframework.batch.repeat.RepeatOperations; |
| 27 | import org.springframework.batch.repeat.support.RepeatTemplate; |
| 28 | import org.springframework.util.Assert; |
| 29 | |
| 30 | /** |
| 31 | * A {@link MethodInterceptor} that can be used to automatically repeat calls to a method on a service. The injected |
| 32 | * {@link RepeatOperations} is used to control the completion of the loop. By default it will repeat until the target |
| 33 | * method returns null. Be careful when injecting a bespoke {@link RepeatOperations} that the loop will actually |
| 34 | * terminate, because the default policy for a vanilla {@link RepeatTemplate} will never complete if the return type of |
| 35 | * the target method is void (the value returned is always not-null, representing the {@link Void#TYPE}). |
| 36 | * |
| 37 | * @author Dave Syer |
| 38 | */ |
| 39 | public class RepeatOperationsInterceptor implements MethodInterceptor { |
| 40 | |
| 41 | private RepeatOperations repeatOperations = new RepeatTemplate(); |
| 42 | |
| 43 | /** |
| 44 | * Setter for the {@link RepeatOperations}. |
| 45 | * |
| 46 | * @param batchTempate |
| 47 | * @throws IllegalArgumentException if the argument is null. |
| 48 | */ |
| 49 | public void setRepeatOperations(RepeatOperations batchTempate) { |
| 50 | Assert.notNull(batchTempate, "'repeatOperations' cannot be null."); |
| 51 | this.repeatOperations = batchTempate; |
| 52 | } |
| 53 | |
| 54 | /** |
| 55 | * Invoke the proceeding method call repeatedly, according to the properties of the injected |
| 56 | * {@link RepeatOperations}. |
| 57 | * |
| 58 | * @see org.aopalliance.intercept.MethodInterceptor#invoke(org.aopalliance.intercept.MethodInvocation) |
| 59 | */ |
| 60 | public Object invoke(final MethodInvocation invocation) throws Throwable { |
| 61 | |
| 62 | repeatOperations.iterate(new RepeatCallback() { |
| 63 | |
| 64 | public ExitStatus doInIteration(RepeatContext context) throws Exception { |
| 65 | try { |
| 66 | |
| 67 | MethodInvocation clone = invocation; |
| 68 | if (invocation instanceof ProxyMethodInvocation) { |
| 69 | clone = ((ProxyMethodInvocation) invocation).invocableClone(); |
| 70 | } else { |
| 71 | throw new IllegalStateException( |
| 72 | "MethodInvocation of the wrong type detected - this should not happen with Spring AOP, so please raise an issue if you see this exception"); |
| 73 | } |
| 74 | |
| 75 | // N.B. discards return value if there is one |
| 76 | if (clone.getMethod().getReturnType().equals(Void.TYPE)) { |
| 77 | clone.proceed(); |
| 78 | return ExitStatus.CONTINUABLE; |
| 79 | } |
| 80 | return new ExitStatus(clone.proceed() != null); |
| 81 | } catch (Throwable e) { |
| 82 | if (e instanceof Exception) { |
| 83 | throw (Exception) e; |
| 84 | } else { |
| 85 | throw new RepeatException("Unexpected error in batch interceptor", e); |
| 86 | } |
| 87 | } |
| 88 | } |
| 89 | |
| 90 | }); |
| 91 | |
| 92 | return null; |
| 93 | } |
| 94 | |
| 95 | } |