001/* 002 * Copyright 2006-2013 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.batch.item.adapter; 018 019import java.util.Arrays; 020import java.util.List; 021 022import org.springframework.batch.item.ItemWriter; 023import org.springframework.beans.BeanWrapper; 024import org.springframework.beans.BeanWrapperImpl; 025import org.springframework.util.Assert; 026 027/** 028 * Delegates processing to a custom method - extracts property values from item 029 * object and uses them as arguments for the delegate method. 030 * 031 * @see ItemWriterAdapter 032 * 033 * @author Robert Kasanicky 034 */ 035public class PropertyExtractingDelegatingItemWriter<T> extends AbstractMethodInvokingDelegator<T> implements 036ItemWriter<T> { 037 038 private String[] fieldsUsedAsTargetMethodArguments; 039 040 /** 041 * Extracts values from item's fields named in 042 * fieldsUsedAsTargetMethodArguments and passes them as arguments to the 043 * delegate method. 044 */ 045 @Override 046 public void write(List<? extends T> items) throws Exception { 047 for (T item : items) { 048 049 // helper for extracting property values from a bean 050 BeanWrapper beanWrapper = new BeanWrapperImpl(item); 051 052 Object[] methodArguments = new Object[fieldsUsedAsTargetMethodArguments.length]; 053 for (int i = 0; i < fieldsUsedAsTargetMethodArguments.length; i++) { 054 methodArguments[i] = beanWrapper.getPropertyValue(fieldsUsedAsTargetMethodArguments[i]); 055 } 056 057 invokeDelegateMethodWithArguments(methodArguments); 058 059 } 060 } 061 062 @Override 063 public void afterPropertiesSet() throws Exception { 064 super.afterPropertiesSet(); 065 Assert.notEmpty(fieldsUsedAsTargetMethodArguments, "fieldsUsedAsTargetMethodArguments must not be empty"); 066 } 067 068 /** 069 * @param fieldsUsedAsMethodArguments the values of the these item's fields 070 * will be used as arguments for the delegate method. Nested property values 071 * are supported, e.g. <code>address.city</code> 072 */ 073 public void setFieldsUsedAsTargetMethodArguments(String[] fieldsUsedAsMethodArguments) { 074 this.fieldsUsedAsTargetMethodArguments = Arrays.asList(fieldsUsedAsMethodArguments).toArray( 075 new String[fieldsUsedAsMethodArguments.length]); 076 } 077 078}