| 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 | package org.springframework.batch.item.data; |
| 17 | |
| 18 | import java.lang.reflect.InvocationTargetException; |
| 19 | import java.util.ArrayList; |
| 20 | import java.util.List; |
| 21 | import java.util.Map; |
| 22 | |
| 23 | import org.apache.commons.logging.Log; |
| 24 | import org.apache.commons.logging.LogFactory; |
| 25 | import org.springframework.batch.item.ExecutionContext; |
| 26 | import org.springframework.batch.item.adapter.AbstractMethodInvokingDelegator.InvocationTargetThrowableWrapper; |
| 27 | import org.springframework.batch.item.adapter.DynamicMethodInvocationException; |
| 28 | import org.springframework.batch.item.support.AbstractItemCountingItemStreamItemReader; |
| 29 | import org.springframework.beans.factory.InitializingBean; |
| 30 | import org.springframework.data.domain.Page; |
| 31 | import org.springframework.data.domain.PageRequest; |
| 32 | import org.springframework.data.domain.Pageable; |
| 33 | import org.springframework.data.domain.Sort; |
| 34 | import org.springframework.data.repository.PagingAndSortingRepository; |
| 35 | import org.springframework.util.Assert; |
| 36 | import org.springframework.util.ClassUtils; |
| 37 | import org.springframework.util.MethodInvoker; |
| 38 | |
| 39 | /** |
| 40 | * <p> |
| 41 | * A {@link org.springframework.batch.item.ItemReader} that reads records utilizing |
| 42 | * a {@link org.springframework.data.repository.PagingAndSortingRepository}. |
| 43 | * </p> |
| 44 | * |
| 45 | * <p> |
| 46 | * Performance of the reader is dependent on the repository implementation, however |
| 47 | * setting a reasonably large page size and matching that to the commit interval should |
| 48 | * yield better performance. |
| 49 | * </p> |
| 50 | * |
| 51 | * <p> |
| 52 | * The reader must be configured with a {@link org.springframework.data.repository.PagingAndSortingRepository}, |
| 53 | * a {@link org.springframework.data.domain.Sort}, and a pageSize greater than 0. |
| 54 | * </p> |
| 55 | * |
| 56 | * <p> |
| 57 | * This implementation is thread safe between calls to {@link #open(ExecutionContext)}, but remember to use |
| 58 | * <code>saveState=false</code> if used in a multi-threaded client (no restart available). |
| 59 | * </p> |
| 60 | * |
| 61 | * @author Michael Minella |
| 62 | * @since 2.2 |
| 63 | */ |
| 64 | @SuppressWarnings("rawtypes") |
| 65 | public class RepositoryItemReader<T> extends AbstractItemCountingItemStreamItemReader<T> implements InitializingBean { |
| 66 | |
| 67 | protected Log logger = LogFactory.getLog(getClass()); |
| 68 | |
| 69 | private PagingAndSortingRepository repository; |
| 70 | |
| 71 | private Sort sort; |
| 72 | |
| 73 | private volatile int page = 0; |
| 74 | |
| 75 | private int pageSize = 10; |
| 76 | |
| 77 | private volatile int current = 0; |
| 78 | |
| 79 | private List arguments; |
| 80 | |
| 81 | private volatile List<T> results; |
| 82 | |
| 83 | private Object lock = new Object(); |
| 84 | |
| 85 | private String methodName; |
| 86 | |
| 87 | public RepositoryItemReader() { |
| 88 | setName(ClassUtils.getShortName(RepositoryItemReader.class)); |
| 89 | } |
| 90 | |
| 91 | /** |
| 92 | * Arguments to be passed to the data providing method. |
| 93 | * |
| 94 | * @param arguments list of method arguments to be passed to the repository |
| 95 | */ |
| 96 | public void setArguments(List arguments) { |
| 97 | this.arguments = arguments; |
| 98 | } |
| 99 | |
| 100 | /** |
| 101 | * Provides ordering of the results so that order is maintained between paged queries |
| 102 | * |
| 103 | * @param sorts the fields to sort by and the directions |
| 104 | */ |
| 105 | public void setSort(Map<String, Sort.Direction> sorts) { |
| 106 | this.sort = convertToSort(sorts); |
| 107 | } |
| 108 | |
| 109 | /** |
| 110 | * @param pageSize The number of items to retrieve per page. |
| 111 | */ |
| 112 | public void setPageSize(int pageSize) { |
| 113 | this.pageSize = pageSize; |
| 114 | } |
| 115 | |
| 116 | /** |
| 117 | * The {@link org.springframework.data.repository.PagingAndSortingRepository} |
| 118 | * implementation used to read input from. |
| 119 | * |
| 120 | * @param repository underlying repository for input to be read from. |
| 121 | */ |
| 122 | public void setRepository(PagingAndSortingRepository repository) { |
| 123 | this.repository = repository; |
| 124 | } |
| 125 | |
| 126 | /** |
| 127 | * Specifies what method on the repository to call. This method must take |
| 128 | * {@link org.springframework.data.domain.Pageable} as the <em>last</em> argument. |
| 129 | * |
| 130 | * @param methodName |
| 131 | */ |
| 132 | public void setMethodName(String methodName) { |
| 133 | this.methodName = methodName; |
| 134 | } |
| 135 | |
| 136 | @Override |
| 137 | public void afterPropertiesSet() throws Exception { |
| 138 | Assert.state(repository != null, "A PagingAndSortingRepository is required"); |
| 139 | Assert.state(pageSize > 0, "Page size must be greater than 0"); |
| 140 | Assert.state(sort != null, "A sort is required"); |
| 141 | } |
| 142 | |
| 143 | @Override |
| 144 | protected T doRead() throws Exception { |
| 145 | |
| 146 | synchronized (lock) { |
| 147 | if(results == null || current >= results.size()) { |
| 148 | |
| 149 | if (logger.isDebugEnabled()) { |
| 150 | logger.debug("Reading page " + page); |
| 151 | } |
| 152 | |
| 153 | results = doPageRead(); |
| 154 | |
| 155 | current = 0; |
| 156 | page ++; |
| 157 | |
| 158 | if(results.size() <= 0) { |
| 159 | return null; |
| 160 | } |
| 161 | } |
| 162 | |
| 163 | if(current < results.size()) { |
| 164 | T curLine = results.get(current); |
| 165 | current++; |
| 166 | return curLine; |
| 167 | } |
| 168 | else { |
| 169 | return null; |
| 170 | } |
| 171 | } |
| 172 | } |
| 173 | |
| 174 | @Override |
| 175 | protected void jumpToItem(int itemLastIndex) throws Exception { |
| 176 | synchronized (lock) { |
| 177 | page = itemLastIndex / pageSize; |
| 178 | current = itemLastIndex % pageSize; |
| 179 | |
| 180 | results = doPageRead(); |
| 181 | page++; |
| 182 | } |
| 183 | } |
| 184 | |
| 185 | /** |
| 186 | * Performs the actual reading of a page via the repository. |
| 187 | * Available for overriding as needed. |
| 188 | * |
| 189 | * @return the list of items that make up the page |
| 190 | * @throws Exception |
| 191 | */ |
| 192 | @SuppressWarnings("unchecked") |
| 193 | protected List<T> doPageRead() throws Exception { |
| 194 | Pageable pageRequest = new PageRequest(page, pageSize, sort); |
| 195 | |
| 196 | MethodInvoker invoker = createMethodInvoker(repository, methodName); |
| 197 | |
| 198 | List parameters = new ArrayList(); |
| 199 | |
| 200 | if(arguments != null && arguments.size() > 0) { |
| 201 | parameters.addAll(arguments); |
| 202 | } |
| 203 | |
| 204 | parameters.add(pageRequest); |
| 205 | |
| 206 | invoker.setArguments(parameters.toArray()); |
| 207 | |
| 208 | Page curPage = (Page) doInvoke(invoker); |
| 209 | |
| 210 | return curPage.getContent(); |
| 211 | } |
| 212 | |
| 213 | @Override |
| 214 | protected void doOpen() throws Exception { |
| 215 | } |
| 216 | |
| 217 | @Override |
| 218 | protected void doClose() throws Exception { |
| 219 | } |
| 220 | |
| 221 | private Sort convertToSort(Map<String, Sort.Direction> sorts) { |
| 222 | List<Sort.Order> sortValues = new ArrayList<Sort.Order>(); |
| 223 | |
| 224 | for (Map.Entry<String, Sort.Direction> curSort : sorts.entrySet()) { |
| 225 | sortValues.add(new Sort.Order(curSort.getValue(), curSort.getKey())); |
| 226 | } |
| 227 | |
| 228 | return new Sort(sortValues); |
| 229 | } |
| 230 | |
| 231 | private Object doInvoke(MethodInvoker invoker) throws Exception{ |
| 232 | try { |
| 233 | invoker.prepare(); |
| 234 | } |
| 235 | catch (ClassNotFoundException e) { |
| 236 | throw new DynamicMethodInvocationException(e); |
| 237 | } |
| 238 | catch (NoSuchMethodException e) { |
| 239 | throw new DynamicMethodInvocationException(e); |
| 240 | } |
| 241 | |
| 242 | try { |
| 243 | return invoker.invoke(); |
| 244 | } |
| 245 | catch (InvocationTargetException e) { |
| 246 | if (e.getCause() instanceof Exception) { |
| 247 | throw (Exception) e.getCause(); |
| 248 | } |
| 249 | else { |
| 250 | throw new InvocationTargetThrowableWrapper(e.getCause()); |
| 251 | } |
| 252 | } |
| 253 | catch (IllegalAccessException e) { |
| 254 | throw new DynamicMethodInvocationException(e); |
| 255 | } |
| 256 | } |
| 257 | |
| 258 | private MethodInvoker createMethodInvoker(Object targetObject, String targetMethod) { |
| 259 | MethodInvoker invoker = new MethodInvoker(); |
| 260 | invoker.setTargetObject(targetObject); |
| 261 | invoker.setTargetMethod(targetMethod); |
| 262 | return invoker; |
| 263 | } |
| 264 | } |