| 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.adapter; |
| 18 | |
| 19 | import java.util.Arrays; |
| 20 | import java.util.List; |
| 21 | |
| 22 | import org.springframework.batch.item.ItemWriter; |
| 23 | import org.springframework.beans.BeanWrapper; |
| 24 | import org.springframework.beans.BeanWrapperImpl; |
| 25 | import org.springframework.util.Assert; |
| 26 | |
| 27 | /** |
| 28 | * Delegates processing to a custom method - extracts property values from item |
| 29 | * object and uses them as arguments for the delegate method. |
| 30 | * |
| 31 | * @see ItemWriterAdapter |
| 32 | * |
| 33 | * @author Robert Kasanicky |
| 34 | */ |
| 35 | public class PropertyExtractingDelegatingItemWriter<T> extends AbstractMethodInvokingDelegator<T> implements |
| 36 | ItemWriter<T> { |
| 37 | |
| 38 | private String[] fieldsUsedAsTargetMethodArguments; |
| 39 | |
| 40 | /** |
| 41 | * Extracts values from item's fields named in |
| 42 | * fieldsUsedAsTargetMethodArguments and passes them as arguments to the |
| 43 | * delegate method. |
| 44 | */ |
| 45 | public void write(List<? extends T> items) throws Exception { |
| 46 | for (T item : items) { |
| 47 | |
| 48 | // helper for extracting property values from a bean |
| 49 | BeanWrapper beanWrapper = new BeanWrapperImpl(item); |
| 50 | |
| 51 | Object[] methodArguments = new Object[fieldsUsedAsTargetMethodArguments.length]; |
| 52 | for (int i = 0; i < fieldsUsedAsTargetMethodArguments.length; i++) { |
| 53 | methodArguments[i] = beanWrapper.getPropertyValue(fieldsUsedAsTargetMethodArguments[i]); |
| 54 | } |
| 55 | |
| 56 | invokeDelegateMethodWithArguments(methodArguments); |
| 57 | |
| 58 | } |
| 59 | } |
| 60 | |
| 61 | public void afterPropertiesSet() throws Exception { |
| 62 | super.afterPropertiesSet(); |
| 63 | Assert.notEmpty(fieldsUsedAsTargetMethodArguments); |
| 64 | } |
| 65 | |
| 66 | /** |
| 67 | * @param fieldsUsedAsMethodArguments the values of the these item's fields |
| 68 | * will be used as arguments for the delegate method. Nested property values |
| 69 | * are supported, e.g. <code>address.city</code> |
| 70 | */ |
| 71 | public void setFieldsUsedAsTargetMethodArguments(String[] fieldsUsedAsMethodArguments) { |
| 72 | this.fieldsUsedAsTargetMethodArguments = Arrays.asList(fieldsUsedAsMethodArguments).toArray( |
| 73 | new String[fieldsUsedAsMethodArguments.length]); |
| 74 | } |
| 75 | |
| 76 | } |