Add support for quotes in DelimitedLineAggregator

Resolves #1139

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/builder/FlatFileItemWriterBuilder.java

@@ -34,6 +34,7 @@ import org.springframework.batch.item.file.transform.LineAggregator;
 import org.springframework.batch.item.file.transform.RecordFieldExtractor;
 import org.springframework.core.io.WritableResource;
 import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
 
 /**
  * A builder implementation for the {@link FlatFileItemWriter}
@@ -424,6 +425,8 @@ public class FlatFileItemWriterBuilder<T> {
 
 		private String delimiter = ",";
 
+		private String quoteCharacter = "";
+
 		private FieldExtractor<T> fieldExtractor;
 
 		private Class<T> sourceType;
@@ -457,6 +460,17 @@ public class FlatFileItemWriterBuilder<T> {
 			return this;
 		}
 
+		/**
+		 * Define the quote character for each delimited field. Default is empty string.
+		 * @param quoteCharacter String used as a quote for the aggregate.
+		 * @return The instance of the builder for chaining.
+		 * @see DelimitedLineAggregator#setQuoteCharacter(String)
+		 */
+		public DelimitedBuilder<T> quoteCharacter(String quoteCharacter) {
+			this.quoteCharacter = quoteCharacter;
+			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
@@ -489,6 +503,9 @@ public class FlatFileItemWriterBuilder<T> {
 			if (this.delimiter != null) {
 				delimitedLineAggregator.setDelimiter(this.delimiter);
 			}
+			if (StringUtils.hasLength(this.quoteCharacter)) {
+				delimitedLineAggregator.setQuoteCharacter(this.quoteCharacter);
+			}
 
 			if (this.fieldExtractor == null) {
 				if (this.sourceType != null && this.sourceType.isRecord()) {

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/transform/DelimitedLineAggregator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2007 the original author or authors.
+ * Copyright 2006-2023 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.
@@ -15,19 +15,24 @@
  */
 package org.springframework.batch.item.file.transform;
 
-import org.springframework.util.StringUtils;
+import java.util.Arrays;
+import java.util.stream.Collectors;
 
 /**
  * A {@link LineAggregator} implementation that converts an object into a delimited list
- * of strings. The default delimiter is a comma.
+ * of strings. The default delimiter is a comma. An optional quote value can be set to add
+ * surrounding quotes for each element of the list. Default is empty string, which means
+ * not quotes.
  *
  * @author Dave Syer
- *
+ * @author Glenn Renfro
  */
 public class DelimitedLineAggregator<T> extends ExtractorLineAggregator<T> {
 
 	private String delimiter = ",";
 
+	private String quoteCharacter = "";
+
 	/**
 	 * Public setter for the delimiter.
 	 * @param delimiter the delimiter to set
@@ -36,9 +41,20 @@ public class DelimitedLineAggregator<T> extends ExtractorLineAggregator<T> {
 		this.delimiter = delimiter;
 	}
 
+	/**
+	 * Setter for the quote character.
+	 * @since 5.1
+	 * @param quoteCharacter the quote character to set
+	 */
+	public void setQuoteCharacter(String quoteCharacter) {
+		this.quoteCharacter = quoteCharacter;
+	}
+
 	@Override
 	public String doAggregate(Object[] fields) {
-		return StringUtils.arrayToDelimitedString(fields, this.delimiter);
+		return Arrays.stream(fields)
+			.map(field -> this.quoteCharacter + field + this.quoteCharacter)
+			.collect(Collectors.joining(this.delimiter));
 	}
 
 }

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/builder/FlatFileItemWriterBuilderTests.java

@@ -153,6 +153,34 @@ class FlatFileItemWriterBuilderTests {
 		assertEquals("HEADER$123$456$FOOTER", readLine("UTF-16LE", output));
 	}
 
+	@Test
+	public void testDelimitedOutputWithEmptyDelimiterAndQuote() throws Exception {
+
+		FileSystemResource output = new FileSystemResource(File.createTempFile("foo", "txt"));
+
+		FlatFileItemWriter<Foo> writer = new FlatFileItemWriterBuilder<Foo>().name("foo")
+			.resource(output)
+			.lineSeparator("$")
+			.delimited()
+			.delimiter("")
+			.quoteCharacter("%")
+			.names("first", "second", "third")
+			.encoding("UTF-16LE")
+			.headerCallback(writer1 -> writer1.append("HEADER"))
+			.footerCallback(writer12 -> writer12.append("FOOTER"))
+			.build();
+
+		ExecutionContext executionContext = new ExecutionContext();
+
+		writer.open(executionContext);
+
+		writer.write(new Chunk<>(new Foo(1, 2, "3"), new Foo(4, 5, "6")));
+
+		writer.close();
+
+		assertEquals("HEADER$%1%%2%%3%$%4%%5%%6%$FOOTER", readLine("UTF-16LE", output));
+	}
+
 	@Test
 	void testDelimitedOutputWithDefaultFieldExtractor() throws Exception {
 

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/transform/DelimitedLineAggregatorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2022 the original author or authors.
+ * Copyright 2006-2023 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.
@@ -22,6 +22,7 @@ import org.junit.jupiter.api.Test;
 
 /**
  * @author Dave Syer
+ * @author Glenn Renfro
  *
  */
 class DelimitedLineAggregatorTests {
@@ -40,6 +41,13 @@ class DelimitedLineAggregatorTests {
 		assertEquals("foo;bar", aggregator.aggregate(new String[] { "foo", "bar" }));
 	}
 
+	@Test
+	public void testSetDelimiterAndQuote() {
+		aggregator.setDelimiter(";");
+		aggregator.setQuoteCharacter("\"");
+		assertEquals("\"foo\";\"bar\"", aggregator.aggregate(new String[] { "foo", "bar" }));
+	}
+
 	@Test
 	void testAggregate() {
 		assertEquals("foo,bar", aggregator.aggregate(new String[] { "foo", "bar" }));