| 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.item.file; |
| 18 | |
| 19 | import java.io.File; |
| 20 | import java.io.IOException; |
| 21 | import java.util.List; |
| 22 | |
| 23 | import org.springframework.batch.item.ExecutionContext; |
| 24 | import org.springframework.batch.item.ItemStream; |
| 25 | import org.springframework.batch.item.ItemStreamException; |
| 26 | import org.springframework.batch.item.ItemWriter; |
| 27 | import org.springframework.batch.item.util.ExecutionContextUserSupport; |
| 28 | import org.springframework.core.io.FileSystemResource; |
| 29 | import org.springframework.core.io.Resource; |
| 30 | import org.springframework.util.Assert; |
| 31 | import org.springframework.util.ClassUtils; |
| 32 | |
| 33 | /** |
| 34 | * Wraps a {@link ResourceAwareItemWriterItemStream} and creates a new output |
| 35 | * resource when the count of items written in current resource exceeds |
| 36 | * {@link #setItemCountLimitPerResource(int)}. Suffix creation can be customized |
| 37 | * with {@link #setResourceSuffixCreator(ResourceSuffixCreator)}. |
| 38 | * |
| 39 | * Note that new resources are created only at chunk boundaries i.e. the number |
| 40 | * of items written into one resource is between the limit set by |
| 41 | * {@link #setItemCountLimitPerResource(int)} and (limit + chunk size). |
| 42 | * |
| 43 | * @param <T> item type |
| 44 | * |
| 45 | * @author Robert Kasanicky |
| 46 | */ |
| 47 | public class MultiResourceItemWriter<T> extends ExecutionContextUserSupport implements ItemWriter<T>, ItemStream { |
| 48 | |
| 49 | final static private String RESOURCE_INDEX_KEY = "resource.index"; |
| 50 | |
| 51 | final static private String CURRENT_RESOURCE_ITEM_COUNT = "resource.item.count"; |
| 52 | |
| 53 | private Resource resource; |
| 54 | |
| 55 | private ResourceAwareItemWriterItemStream<? super T> delegate; |
| 56 | |
| 57 | private int itemCountLimitPerResource = Integer.MAX_VALUE; |
| 58 | |
| 59 | private int currentResourceItemCount = 0; |
| 60 | |
| 61 | private int resourceIndex = 1; |
| 62 | |
| 63 | private ResourceSuffixCreator suffixCreator = new SimpleResourceSuffixCreator(); |
| 64 | |
| 65 | private boolean saveState = true; |
| 66 | |
| 67 | private boolean opened = false; |
| 68 | |
| 69 | public MultiResourceItemWriter() { |
| 70 | setName(ClassUtils.getShortName(MultiResourceItemWriter.class)); |
| 71 | } |
| 72 | |
| 73 | public void write(List<? extends T> items) throws Exception { |
| 74 | if (!opened) { |
| 75 | File file = setResourceToDelegate(); |
| 76 | // create only if write is called |
| 77 | file.createNewFile(); |
| 78 | Assert.state(file.canWrite(), "Output resource " + file.getAbsolutePath() + " must be writable"); |
| 79 | delegate.open(new ExecutionContext()); |
| 80 | opened = true; |
| 81 | } |
| 82 | delegate.write(items); |
| 83 | currentResourceItemCount += items.size(); |
| 84 | if (currentResourceItemCount >= itemCountLimitPerResource) { |
| 85 | delegate.close(); |
| 86 | resourceIndex++; |
| 87 | currentResourceItemCount = 0; |
| 88 | setResourceToDelegate(); |
| 89 | opened = false; |
| 90 | } |
| 91 | } |
| 92 | |
| 93 | /** |
| 94 | * Allows customization of the suffix of the created resources based on the |
| 95 | * index. |
| 96 | */ |
| 97 | public void setResourceSuffixCreator(ResourceSuffixCreator suffixCreator) { |
| 98 | this.suffixCreator = suffixCreator; |
| 99 | } |
| 100 | |
| 101 | /** |
| 102 | * After this limit is exceeded the next chunk will be written into newly |
| 103 | * created resource. |
| 104 | */ |
| 105 | public void setItemCountLimitPerResource(int itemCountLimitPerResource) { |
| 106 | this.itemCountLimitPerResource = itemCountLimitPerResource; |
| 107 | } |
| 108 | |
| 109 | /** |
| 110 | * Delegate used for actual writing of the output. |
| 111 | */ |
| 112 | public void setDelegate(ResourceAwareItemWriterItemStream<? super T> delegate) { |
| 113 | this.delegate = delegate; |
| 114 | } |
| 115 | |
| 116 | /** |
| 117 | * Prototype for output resources. Actual output files will be created in |
| 118 | * the same directory and use the same name as this prototype with appended |
| 119 | * suffix (according to |
| 120 | * {@link #setResourceSuffixCreator(ResourceSuffixCreator)}. |
| 121 | */ |
| 122 | public void setResource(Resource resource) { |
| 123 | this.resource = resource; |
| 124 | } |
| 125 | |
| 126 | public void setSaveState(boolean saveState) { |
| 127 | this.saveState = saveState; |
| 128 | } |
| 129 | |
| 130 | public void close() throws ItemStreamException { |
| 131 | resourceIndex = 1; |
| 132 | currentResourceItemCount = 0; |
| 133 | if (opened) { |
| 134 | delegate.close(); |
| 135 | } |
| 136 | } |
| 137 | |
| 138 | public void open(ExecutionContext executionContext) throws ItemStreamException { |
| 139 | resourceIndex = executionContext.getInt(getKey(RESOURCE_INDEX_KEY), 1); |
| 140 | currentResourceItemCount = executionContext.getInt(getKey(CURRENT_RESOURCE_ITEM_COUNT), 0); |
| 141 | |
| 142 | try { |
| 143 | setResourceToDelegate(); |
| 144 | } |
| 145 | catch (IOException e) { |
| 146 | throw new ItemStreamException("Couldn't assign resource", e); |
| 147 | } |
| 148 | |
| 149 | if (executionContext.containsKey(getKey(CURRENT_RESOURCE_ITEM_COUNT))) { |
| 150 | // It's a restart |
| 151 | delegate.open(executionContext); |
| 152 | } |
| 153 | else { |
| 154 | opened = false; |
| 155 | } |
| 156 | } |
| 157 | |
| 158 | public void update(ExecutionContext executionContext) throws ItemStreamException { |
| 159 | if (saveState) { |
| 160 | if (opened) { |
| 161 | delegate.update(executionContext); |
| 162 | } |
| 163 | executionContext.putInt(getKey(CURRENT_RESOURCE_ITEM_COUNT), currentResourceItemCount); |
| 164 | executionContext.putInt(getKey(RESOURCE_INDEX_KEY), resourceIndex); |
| 165 | } |
| 166 | } |
| 167 | |
| 168 | /** |
| 169 | * Create output resource (if necessary) and point the delegate to it. |
| 170 | */ |
| 171 | private File setResourceToDelegate() throws IOException { |
| 172 | String path = resource.getFile().getAbsolutePath() + suffixCreator.getSuffix(resourceIndex); |
| 173 | File file = new File(path); |
| 174 | delegate.setResource(new FileSystemResource(file)); |
| 175 | return file; |
| 176 | } |
| 177 | } |