| 1 | /* |
| 2 | * Copyright 2012 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.item.data; |
| 18 | |
| 19 | import java.util.ArrayList; |
| 20 | import java.util.List; |
| 21 | |
| 22 | import org.springframework.batch.item.ItemWriter; |
| 23 | import org.springframework.beans.factory.InitializingBean; |
| 24 | import org.springframework.data.mongodb.core.MongoOperations; |
| 25 | import org.springframework.transaction.support.TransactionSynchronizationAdapter; |
| 26 | import org.springframework.transaction.support.TransactionSynchronizationManager; |
| 27 | import org.springframework.util.Assert; |
| 28 | import org.springframework.util.CollectionUtils; |
| 29 | import org.springframework.util.StringUtils; |
| 30 | |
| 31 | /** |
| 32 | * <p> |
| 33 | * A {@link ItemWriter} implementation that writes to a MongoDB store using an implementation of Spring Data's |
| 34 | * {@link MongoOperations}. Since MongoDB is not a transactional store, a best effort is made to persist |
| 35 | * written data at the last moment, yet still honor job status contracts. No attempt to roll back is made |
| 36 | * if an error occurs during writing. |
| 37 | * </p> |
| 38 | * |
| 39 | * <p> |
| 40 | * This writer is thread safe once all properties are set (normal singleton behavior) so it can be used in multiple |
| 41 | * concurrent transactions. |
| 42 | * </p> |
| 43 | * |
| 44 | * @author Michael Minella |
| 45 | * |
| 46 | */ |
| 47 | public class MongoItemWriter<T> implements ItemWriter<T>, InitializingBean { |
| 48 | |
| 49 | private static final String BUFFER_KEY_PREFIX = MongoItemWriter.class.getName() + ".BUFFER_KEY"; |
| 50 | private MongoOperations template; |
| 51 | private final String bufferKey; |
| 52 | private String collection; |
| 53 | private boolean delete = false; |
| 54 | |
| 55 | public MongoItemWriter() { |
| 56 | super(); |
| 57 | this.bufferKey = BUFFER_KEY_PREFIX + "." + hashCode(); |
| 58 | } |
| 59 | |
| 60 | /** |
| 61 | * Indicates if the items being passed to the writer are to be saved or |
| 62 | * removed from the data store. If set to false (default), the items will |
| 63 | * be saved. If set to true, the items will be removed. |
| 64 | * |
| 65 | * @param delete removal indicator |
| 66 | */ |
| 67 | public void setDelete(boolean delete) { |
| 68 | this.delete = delete; |
| 69 | } |
| 70 | |
| 71 | /** |
| 72 | * Set the {@link MongoOperations} to be used to save items to be written. |
| 73 | * |
| 74 | * @param template the template implementation to be used. |
| 75 | */ |
| 76 | public void setTemplate(MongoOperations template) { |
| 77 | this.template = template; |
| 78 | } |
| 79 | |
| 80 | /** |
| 81 | * Set the name of the Mongo collection to be written to. |
| 82 | * |
| 83 | * @param collection the name of the collection. |
| 84 | */ |
| 85 | public void setCollection(String collection) { |
| 86 | this.collection = collection; |
| 87 | } |
| 88 | |
| 89 | /** |
| 90 | * If a transaction is active, buffer items to be written just before commit. |
| 91 | * Otherwise write items using the provided template. |
| 92 | * |
| 93 | * @see org.springframework.batch.item.ItemWriter#write(List) |
| 94 | */ |
| 95 | public void write(List<? extends T> items) throws Exception { |
| 96 | if(!transactionActive()) { |
| 97 | doWrite(items); |
| 98 | return; |
| 99 | } |
| 100 | |
| 101 | List bufferedItems = getCurrentBuffer(); |
| 102 | bufferedItems.addAll(items); |
| 103 | } |
| 104 | |
| 105 | /** |
| 106 | * Performs the actual write to the store via the template. |
| 107 | * This can be overridden by a subclass if necessary. |
| 108 | * |
| 109 | * @param items the list of items to be persisted. |
| 110 | */ |
| 111 | protected void doWrite(List<? extends T> items) { |
| 112 | if(! CollectionUtils.isEmpty(items)) { |
| 113 | if(delete) { |
| 114 | if(StringUtils.hasText(collection)) { |
| 115 | for (Object object : items) { |
| 116 | template.remove(object, collection); |
| 117 | } |
| 118 | } |
| 119 | else { |
| 120 | for (Object object : items) { |
| 121 | template.remove(object); |
| 122 | } |
| 123 | } |
| 124 | } |
| 125 | else { |
| 126 | if(StringUtils.hasText(collection)) { |
| 127 | for (Object object : items) { |
| 128 | template.save(object, collection); |
| 129 | } |
| 130 | } |
| 131 | else { |
| 132 | for (Object object : items) { |
| 133 | template.save(object); |
| 134 | } |
| 135 | } |
| 136 | } |
| 137 | } |
| 138 | } |
| 139 | |
| 140 | private boolean transactionActive() { |
| 141 | return TransactionSynchronizationManager.isActualTransactionActive(); |
| 142 | } |
| 143 | |
| 144 | private List<? extends T> getCurrentBuffer() { |
| 145 | if(!TransactionSynchronizationManager.hasResource(bufferKey)) { |
| 146 | TransactionSynchronizationManager.bindResource(bufferKey, new ArrayList()); |
| 147 | |
| 148 | TransactionSynchronizationManager.registerSynchronization(new TransactionSynchronizationAdapter() { |
| 149 | @Override |
| 150 | public void beforeCommit(boolean readOnly) { |
| 151 | List items = (List) TransactionSynchronizationManager.getResource(bufferKey); |
| 152 | |
| 153 | if(!CollectionUtils.isEmpty(items)) { |
| 154 | if(!readOnly) { |
| 155 | doWrite(items); |
| 156 | } |
| 157 | } |
| 158 | } |
| 159 | |
| 160 | @Override |
| 161 | public void afterCompletion(int status) { |
| 162 | if(TransactionSynchronizationManager.hasResource(bufferKey)) { |
| 163 | TransactionSynchronizationManager.unbindResource(bufferKey); |
| 164 | } |
| 165 | } |
| 166 | }); |
| 167 | } |
| 168 | |
| 169 | return (List) TransactionSynchronizationManager.getResource(bufferKey); |
| 170 | } |
| 171 | |
| 172 | public void afterPropertiesSet() throws Exception { |
| 173 | Assert.state(template != null, "A MongoOperations implementation is required."); |
| 174 | } |
| 175 | } |