org.springframework.batch.item.file.builder.FlatFileItemWriterBuilder Maven / Gradle / Ivy
/*
* Copyright 2016-2018 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.builder;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Locale;
import org.springframework.batch.item.file.FlatFileFooterCallback;
import org.springframework.batch.item.file.FlatFileHeaderCallback;
import org.springframework.batch.item.file.FlatFileItemWriter;
import org.springframework.batch.item.file.transform.BeanWrapperFieldExtractor;
import org.springframework.batch.item.file.transform.DelimitedLineAggregator;
import org.springframework.batch.item.file.transform.FieldExtractor;
import org.springframework.batch.item.file.transform.FormatterLineAggregator;
import org.springframework.batch.item.file.transform.LineAggregator;
import org.springframework.core.io.Resource;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;
/**
* A builder implementation for the {@link FlatFileItemWriter}
*
* @author Michael Minella
* @author Glenn Renfro
* @author Mahmoud Ben Hassine
* @since 4.0
* @see FlatFileItemWriter
*/
public class FlatFileItemWriterBuilder {
private Resource resource;
private boolean forceSync = false;
private String lineSeparator = FlatFileItemWriter.DEFAULT_LINE_SEPARATOR;
private LineAggregator lineAggregator;
private String encoding = FlatFileItemWriter.DEFAULT_CHARSET;
private boolean shouldDeleteIfExists = true;
private boolean append = false;
private boolean shouldDeleteIfEmpty = false;
private FlatFileHeaderCallback headerCallback;
private FlatFileFooterCallback footerCallback;
private boolean transactional = FlatFileItemWriter.DEFAULT_TRANSACTIONAL;
private boolean saveState = true;
private String name;
private DelimitedBuilder delimitedBuilder;
private FormattedBuilder formattedBuilder;
/**
* Configure if the state of the {@link org.springframework.batch.item.ItemStreamSupport}
* should be persisted within the {@link org.springframework.batch.item.ExecutionContext}
* for restart purposes.
*
* @param saveState defaults to true
* @return The current instance of the builder.
*/
public FlatFileItemWriterBuilder saveState(boolean saveState) {
this.saveState = saveState;
return this;
}
/**
* The name used to calculate the key within the
* {@link org.springframework.batch.item.ExecutionContext}. Required if
* {@link #saveState(boolean)} is set to true.
*
* @param name name of the reader instance
* @return The current instance of the builder.
* @see org.springframework.batch.item.ItemStreamSupport#setName(String)
*/
public FlatFileItemWriterBuilder name(String name) {
this.name = name;
return this;
}
/**
* The {@link Resource} to be used as output.
*
* @param resource the output of the writer.
* @return The current instance of the builder.
* @see FlatFileItemWriter#setResource(Resource)
*/
public FlatFileItemWriterBuilder resource(Resource resource) {
this.resource = resource;
return this;
}
/**
* A flag indicating that changes should be force-synced to disk on flush. Defaults
* to false.
*
* @param forceSync value to set the flag to
* @return The current instance of the builder.
* @see FlatFileItemWriter#setForceSync(boolean)
*/
public FlatFileItemWriterBuilder forceSync(boolean forceSync) {
this.forceSync = forceSync;
return this;
}
/**
* String used to separate lines in output. Defaults to the System property
* line.separator.
*
* @param lineSeparator value to use for a line separator
* @return The current instance of the builder.
* @see FlatFileItemWriter#setLineSeparator(String)
*/
public FlatFileItemWriterBuilder lineSeparator(String lineSeparator) {
this.lineSeparator = lineSeparator;
return this;
}
/**
* Line aggregator used to build the String version of each item.
*
* @param lineAggregator {@link LineAggregator} implementation
* @return The current instance of the builder.
* @see FlatFileItemWriter#setLineAggregator(LineAggregator)
*/
public FlatFileItemWriterBuilder lineAggregator(LineAggregator lineAggregator) {
this.lineAggregator = lineAggregator;
return this;
}
/**
* Encoding used for output.
*
* @param encoding encoding type.
* @return The current instance of the builder.
* @see FlatFileItemWriter#setEncoding(String)
*/
public FlatFileItemWriterBuilder encoding(String encoding) {
this.encoding = encoding;
return this;
}
/**
* If set to true, once the step is complete, if the resource previously provided is
* empty, it will be deleted.
*
* @param shouldDelete defaults to false
* @return The current instance of the builder
* @see FlatFileItemWriter#setShouldDeleteIfEmpty(boolean)
*/
public FlatFileItemWriterBuilder shouldDeleteIfEmpty(boolean shouldDelete) {
this.shouldDeleteIfEmpty = shouldDelete;
return this;
}
/**
* If set to true, upon the start of the step, if the resource already exists, it will
* be deleted and recreated.
*
* @param shouldDelete defaults to true
* @return The current instance of the builder
* @see FlatFileItemWriter#setShouldDeleteIfExists(boolean)
*/
public FlatFileItemWriterBuilder shouldDeleteIfExists(boolean shouldDelete) {
this.shouldDeleteIfExists = shouldDelete;
return this;
}
/**
* If set to true and the file exists, the output will be appended to the existing
* file.
*
* @param append defaults to false
* @return The current instance of the builder
* @see FlatFileItemWriter#setAppendAllowed(boolean)
*/
public FlatFileItemWriterBuilder append(boolean append) {
this.append = append;
return this;
}
/**
* A callback for header processing.
*
* @param callback {@link FlatFileHeaderCallback} impl
* @return The current instance of the builder
* @see FlatFileItemWriter#setHeaderCallback(FlatFileHeaderCallback)
*/
public FlatFileItemWriterBuilder headerCallback(FlatFileHeaderCallback callback) {
this.headerCallback = callback;
return this;
}
/**
* A callback for footer processing
* @param callback {@link FlatFileFooterCallback} impl
* @return The current instance of the builder
* @see FlatFileItemWriter#setFooterCallback(FlatFileFooterCallback)
*/
public FlatFileItemWriterBuilder footerCallback(FlatFileFooterCallback callback) {
this.footerCallback = callback;
return this;
}
/**
* If set to true, the flushing of the buffer is delayed while a transaction is active.
*
* @param transactional defaults to true
* @return The current instance of the builder
* @see FlatFileItemWriter#setTransactional(boolean)
*/
public FlatFileItemWriterBuilder transactional(boolean transactional) {
this.transactional = transactional;
return this;
}
/**
* Returns an instance of a {@link DelimitedBuilder} for building a
* {@link DelimitedLineAggregator}. The {@link DelimitedLineAggregator} configured by
* this builder will only be used if one is not explicitly configured via
* {@link FlatFileItemWriterBuilder#lineAggregator}
*
* @return a {@link DelimitedBuilder}
*
*/
public DelimitedBuilder delimited() {
this.delimitedBuilder = new DelimitedBuilder<>(this);
return this.delimitedBuilder;
}
/**
* Returns an instance of a {@link FormattedBuilder} for building a
* {@link FormatterLineAggregator}. The {@link FormatterLineAggregator} configured by
* this builder will only be used if one is not explicitly configured via
* {@link FlatFileItemWriterBuilder#lineAggregator}
*
* @return a {@link FormattedBuilder}
*
*/
public FormattedBuilder formatted() {
this.formattedBuilder = new FormattedBuilder<>(this);
return this.formattedBuilder;
}
/**
* A builder for constructing a {@link FormatterLineAggregator}.
*
* @param the type of the parent {@link FlatFileItemWriterBuilder}
*/
public static class FormattedBuilder {
private FlatFileItemWriterBuilder parent;
private String format;
private Locale locale = Locale.getDefault();
private int maximumLength = 0;
private int minimumLength = 0;
private FieldExtractor fieldExtractor;
private List names = new ArrayList<>();
protected FormattedBuilder(FlatFileItemWriterBuilder parent) {
this.parent = parent;
}
/**
* Set the format string used to aggregate items
* @param format used to aggregate items
* @return The instance of the builder for chaining.
*/
public FormattedBuilder format(String format) {
this.format = format;
return this;
}
/**
* Set the locale.
* @param locale to use
* @return The instance of the builder for chaining.
*/
public FormattedBuilder locale(Locale locale) {
this.locale = locale;
return this;
}
/**
* Set the minimum length of the formatted string. If this is not set
* the default is to allow any length.
* @param minimumLength of the formatted string
* @return The instance of the builder for chaining.
*/
public FormattedBuilder minimumLength(int minimumLength) {
this.minimumLength = minimumLength;
return this;
}
/**
* Set the maximum length of the formatted string. If this is not set
* the default is to allow any length.
* @param maximumLength of the formatted string
* @return The instance of the builder for chaining.
*/
public FormattedBuilder maximumLength(int maximumLength) {
this.maximumLength = maximumLength;
return this;
}
/**
* Set the {@link FieldExtractor} to use to extract fields from each item.
* @param fieldExtractor to use to extract fields from each item
* @return The current instance of the builder
*/
public FlatFileItemWriterBuilder fieldExtractor(FieldExtractor fieldExtractor) {
this.fieldExtractor = fieldExtractor;
return this.parent;
}
/**
* Names of each of the fields within the fields that are returned in the order
* they occur within the formatted file. These names will be used to create
* a {@link BeanWrapperFieldExtractor} only if no explicit field extractor
* is set via {@link FormattedBuilder#fieldExtractor(FieldExtractor)}.
*
* @param names names of each field
* @return The parent {@link FlatFileItemWriterBuilder}
* @see BeanWrapperFieldExtractor#setNames(String[])
*/
public FlatFileItemWriterBuilder names(String[] names) {
this.names.addAll(Arrays.asList(names));
return this.parent;
}
public FormatterLineAggregator build() {
Assert.notNull(this.format, "A format is required");
Assert.isTrue((this.names != null && !this.names.isEmpty()) || this.fieldExtractor != null,
"A list of field names or a field extractor is required");
FormatterLineAggregator formatterLineAggregator = new FormatterLineAggregator<>();
formatterLineAggregator.setFormat(this.format);
formatterLineAggregator.setLocale(this.locale);
formatterLineAggregator.setMinimumLength(this.minimumLength);
formatterLineAggregator.setMaximumLength(this.maximumLength);
if (this.fieldExtractor == null) {
BeanWrapperFieldExtractor beanWrapperFieldExtractor = new BeanWrapperFieldExtractor<>();
beanWrapperFieldExtractor.setNames(this.names.toArray(new String[this.names.size()]));
try {
beanWrapperFieldExtractor.afterPropertiesSet();
}
catch (Exception e) {
throw new IllegalStateException("Unable to initialize FormatterLineAggregator", e);
}
this.fieldExtractor = beanWrapperFieldExtractor;
}
formatterLineAggregator.setFieldExtractor(this.fieldExtractor);
return formatterLineAggregator;
}
}
/**
* A builder for constructing a {@link DelimitedLineAggregator}
*
* @param the type of the parent {@link FlatFileItemWriterBuilder}
*/
public static class DelimitedBuilder {
private FlatFileItemWriterBuilder parent;
private List names = new ArrayList<>();
private String delimiter = ",";
private FieldExtractor fieldExtractor;
protected DelimitedBuilder(FlatFileItemWriterBuilder parent) {
this.parent = parent;
}
/**
* Define the delimiter for the file.
*
* @param delimiter String used as a delimiter between fields.
* @return The instance of the builder for chaining.
* @see DelimitedLineAggregator#setDelimiter(String)
*/
public DelimitedBuilder delimiter(String delimiter) {
this.delimiter = delimiter;
return this;
}
/**
* Names of each of the fields within the fields that are returned in the order
* they occur within the delimited file. These names will be used to create
* a {@link BeanWrapperFieldExtractor} only if no explicit field extractor
* is set via {@link DelimitedBuilder#fieldExtractor(FieldExtractor)}.
*
* @param names names of each field
* @return The parent {@link FlatFileItemWriterBuilder}
* @see BeanWrapperFieldExtractor#setNames(String[])
*/
public FlatFileItemWriterBuilder names(String[] names) {
this.names.addAll(Arrays.asList(names));
return this.parent;
}
/**
* Set the {@link FieldExtractor} to use to extract fields from each item.
* @param fieldExtractor to use to extract fields from each item
* @return The parent {@link FlatFileItemWriterBuilder}
*/
public FlatFileItemWriterBuilder fieldExtractor(FieldExtractor fieldExtractor) {
this.fieldExtractor = fieldExtractor;
return this.parent;
}
public DelimitedLineAggregator build() {
Assert.isTrue((this.names != null && !this.names.isEmpty()) || this.fieldExtractor != null,
"A list of field names or a field extractor is required");
DelimitedLineAggregator delimitedLineAggregator = new DelimitedLineAggregator<>();
if (StringUtils.hasLength(this.delimiter)) {
delimitedLineAggregator.setDelimiter(this.delimiter);
}
if (this.fieldExtractor == null) {
BeanWrapperFieldExtractor beanWrapperFieldExtractor = new BeanWrapperFieldExtractor<>();
beanWrapperFieldExtractor.setNames(this.names.toArray(new String[this.names.size()]));
try {
beanWrapperFieldExtractor.afterPropertiesSet();
}
catch (Exception e) {
throw new IllegalStateException("Unable to initialize DelimitedLineAggregator", e);
}
this.fieldExtractor = beanWrapperFieldExtractor;
}
delimitedLineAggregator.setFieldExtractor(this.fieldExtractor);
return delimitedLineAggregator;
}
}
/**
* Validates and builds a {@link FlatFileItemWriter}.
*
* @return a {@link FlatFileItemWriter}
*/
public FlatFileItemWriter build() {
Assert.isTrue(this.lineAggregator != null || this.delimitedBuilder != null || this.formattedBuilder != null,
"A LineAggregator or a DelimitedBuilder or a FormattedBuilder is required");
Assert.notNull(this.resource, "A Resource is required");
if(this.saveState) {
Assert.hasText(this.name, "A name is required when saveState is true");
}
FlatFileItemWriter writer = new FlatFileItemWriter<>();
writer.setName(this.name);
writer.setAppendAllowed(this.append);
writer.setEncoding(this.encoding);
writer.setFooterCallback(this.footerCallback);
writer.setForceSync(this.forceSync);
writer.setHeaderCallback(this.headerCallback);
if (this.lineAggregator == null) {
Assert.state(this.delimitedBuilder == null || this.formattedBuilder == null,
"Either a DelimitedLineAggregator or a FormatterLineAggregator should be provided, but not both");
if (this.delimitedBuilder != null) {
this.lineAggregator = this.delimitedBuilder.build();
}
else {
this.lineAggregator = this.formattedBuilder.build();
}
}
writer.setLineAggregator(this.lineAggregator);
writer.setLineSeparator(this.lineSeparator);
writer.setResource(this.resource);
writer.setSaveState(this.saveState);
writer.setShouldDeleteIfEmpty(this.shouldDeleteIfEmpty);
writer.setShouldDeleteIfExists(this.shouldDeleteIfExists);
writer.setTransactional(this.transactional);
return writer;
}
}