001/* 002 * Copyright 2006-2018 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.file; 018 019import java.util.List; 020 021import org.springframework.batch.item.file.transform.LineAggregator; 022import org.springframework.batch.item.support.AbstractFileItemWriter; 023import org.springframework.core.io.Resource; 024import org.springframework.util.Assert; 025import org.springframework.util.ClassUtils; 026 027/** 028 * This class is an item writer that writes data to a file or stream. The writer 029 * also provides restart. The location of the output file is defined by a 030 * {@link Resource} and must represent a writable file.<br> 031 * 032 * Uses buffered writer to improve performance.<br> 033 * 034 * The implementation is <b>not</b> thread-safe. 035 * 036 * @author Waseem Malik 037 * @author Tomas Slanina 038 * @author Robert Kasanicky 039 * @author Dave Syer 040 * @author Michael Minella 041 * @author Mahmoud Ben Hassine 042 */ 043public class FlatFileItemWriter<T> extends AbstractFileItemWriter<T> { 044 045 protected LineAggregator<T> lineAggregator; 046 047 public FlatFileItemWriter() { 048 this.setExecutionContextName(ClassUtils.getShortName(FlatFileItemWriter.class)); 049 } 050 051 /** 052 * Assert that mandatory properties (lineAggregator) are set. 053 * 054 * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet() 055 */ 056 @Override 057 public void afterPropertiesSet() throws Exception { 058 Assert.notNull(lineAggregator, "A LineAggregator must be provided."); 059 if (append) { 060 shouldDeleteIfExists = false; 061 } 062 } 063 064 /** 065 * Public setter for the {@link LineAggregator}. This will be used to 066 * translate the item into a line for output. 067 * 068 * @param lineAggregator the {@link LineAggregator} to set 069 */ 070 public void setLineAggregator(LineAggregator<T> lineAggregator) { 071 this.lineAggregator = lineAggregator; 072 } 073 074 @Override 075 public String doWrite(List<? extends T> items) { 076 StringBuilder lines = new StringBuilder(); 077 for (T item : items) { 078 lines.append(this.lineAggregator.aggregate(item)).append(this.lineSeparator); 079 } 080 return lines.toString(); 081 } 082 083}