Add support for 'standalone' attribute in StaxEventItemWriter

Issue #758

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/xml/StaxEventItemWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2017 the original author or authors.
+ * Copyright 2006-2020 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.
@@ -72,7 +72,7 @@ import org.springframework.util.StringUtils;
  * @author Peter Zozom
  * @author Robert Kasanicky
  * @author Michael Minella
- * 
+ * @author Parikshit Dutta
  */
 public class StaxEventItemWriter<T> extends AbstractItemStreamItemWriter<T> implements
 ResourceAwareItemWriterItemStream<T>, InitializingBean {
@@ -85,6 +85,9 @@ ResourceAwareItemWriterItemStream<T>, InitializingBean {
 	// default encoding
 	public static final String DEFAULT_XML_VERSION = "1.0";
 
+	// default standalone document declaration, value not set
+	public static final Boolean DEFAULT_STANDALONE_DOCUMENT = null;
+
 	// default root tag name
 	public static final String DEFAULT_ROOT_TAG_NAME = "root";
 
@@ -109,6 +112,9 @@ ResourceAwareItemWriterItemStream<T>, InitializingBean {
 	// XML version
 	private String version = DEFAULT_XML_VERSION;
 
+	// standalone header attribute
+	private Boolean standalone = DEFAULT_STANDALONE_DOCUMENT;
+
 	// name of the root tag
 	private String rootTagName = DEFAULT_ROOT_TAG_NAME;
 
@@ -270,6 +276,29 @@ ResourceAwareItemWriterItemStream<T>, InitializingBean {
 		this.version = version;
 	}
 
+	/**
+	 * Get used standalone document declaration.
+	 *
+	 * @return the standalone document declaration used
+	 *
+	 * @since 4.3
+	 */
+	public Boolean getStandalone() {
+		return standalone;
+	}
+
+	/**
+	 * Set standalone document declaration to be used for output XML. If not set,
+	 * standalone document declaration will be omitted.
+	 *
+	 * @param standalone the XML standalone document declaration to be used
+	 *
+	 * @since 4.3
+	 */
+	public void setStandalone(Boolean standalone) {
+		this.standalone = standalone;
+	}
+
 	/**
 	 * Get the tag name of the root element.
 	 * 
@@ -606,7 +635,12 @@ ResourceAwareItemWriterItemStream<T>, InitializingBean {
 		XMLEventFactory factory = createXmlEventFactory();
 
 		// write start document
-		writer.add(factory.createStartDocument(getEncoding(), getVersion()));
+		if (getStandalone()==null) {
+			writer.add(factory.createStartDocument(getEncoding(), getVersion()));
+		}
+		else {
+			writer.add(factory.createStartDocument(getEncoding(), getVersion(), getStandalone()));
+		}
 
 		// write root tag
 		writer.add(factory.createStartElement(getRootTagNamespacePrefix(), getRootTagNamespace(), getRootTagName()));

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/xml/builder/StaxEventItemWriterBuilder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017 the original author or authors.
+ * Copyright 2017-2020 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.
@@ -27,6 +27,7 @@ import org.springframework.util.Assert;
  * A builder for the {@link StaxEventItemWriter}.
  *
  * @author Michael Minella
+ * @author Parikshit Dutta
  * @since 4.0
  * @see StaxEventItemWriter
  */
@@ -50,6 +51,8 @@ public class StaxEventItemWriterBuilder<T> {
 
 	private String version = StaxEventItemWriter.DEFAULT_XML_VERSION;
 
+	private Boolean standalone = StaxEventItemWriter.DEFAULT_STANDALONE_DOCUMENT;
+
 	private String rootTagName = StaxEventItemWriter.DEFAULT_ROOT_TAG_NAME;
 
 	private Map<String, String> rootElementAttributes;
@@ -188,7 +191,7 @@ public class StaxEventItemWriterBuilder<T> {
 	 *
 	 * @param version XML version
 	 * @return the current instance of the builder
-	 * @see StaxEventItemWriter#version
+	 * @see StaxEventItemWriter#setVersion(String)
 	 */
 	public StaxEventItemWriterBuilder<T> version(String version) {
 		this.version = version;
@@ -196,6 +199,21 @@ public class StaxEventItemWriterBuilder<T> {
 		return this;
 	}
 
+	/**
+	 * Standalone document declaration for the output document. Defaults to null.
+	 *
+	 * @param standalone Boolean standalone document declaration
+	 * @return the current instance of the builder
+	 * @see StaxEventItemWriter#setStandalone(Boolean)
+	 *
+	 * @since 4.3
+	 */
+	public StaxEventItemWriterBuilder<T> standalone(Boolean standalone) {
+		this.standalone = standalone;
+
+		return this;
+	}
+
 	/**
 	 * The name of the root tag for the output document.
 	 *
@@ -278,6 +296,7 @@ public class StaxEventItemWriterBuilder<T> {
 		writer.setTransactional(this.transactional);
 		writer.setVersion(this.version);
 		writer.setName(this.name);
+		writer.setStandalone(this.standalone);
 
 		return writer;
 	}