org.springframework.batch.item.file.FlatFileItemWriter.java Source code

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Here is the source code for org.springframework.batch.item.file.FlatFileItemWriter.java

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/*
 * Copyright 2006-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.batch.item.file;

import java.util.List;

import org.springframework.batch.item.file.transform.LineAggregator;
import org.springframework.batch.item.support.AbstractFileItemWriter;
import org.springframework.core.io.Resource;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;

/**
 * This class is an item writer that writes data to a file or stream. The writer
 * also provides restart. The location of the output file is defined by a
 * {@link Resource} and must represent a writable file.<br>
 * 
 * Uses buffered writer to improve performance.<br>
 * 
 * The implementation is <b>not</b> thread-safe.
 * 
 * @author Waseem Malik
 * @author Tomas Slanina
 * @author Robert Kasanicky
 * @author Dave Syer
 * @author Michael Minella
 * @author Mahmoud Ben Hassine
 */
public class FlatFileItemWriter<T> extends AbstractFileItemWriter<T> {

    protected LineAggregator<T> lineAggregator;

    public FlatFileItemWriter() {
        this.setExecutionContextName(ClassUtils.getShortName(FlatFileItemWriter.class));
    }

    /**
     * Assert that mandatory properties (lineAggregator) are set.
     * 
     * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet()
     */
    @Override
    public void afterPropertiesSet() throws Exception {
        Assert.notNull(lineAggregator, "A LineAggregator must be provided.");
        if (append) {
            shouldDeleteIfExists = false;
        }
    }

    /**
     * Public setter for the {@link LineAggregator}. This will be used to
     * translate the item into a line for output.
     * 
     * @param lineAggregator the {@link LineAggregator} to set
     */
    public void setLineAggregator(LineAggregator<T> lineAggregator) {
        this.lineAggregator = lineAggregator;
    }

    @Override
    public String doWrite(List<? extends T> items) {
        StringBuilder lines = new StringBuilder();
        for (T item : items) {
            lines.append(this.lineAggregator.aggregate(item)).append(this.lineSeparator);
        }
        return lines.toString();
    }

}