Create a builder for the StaxEventItemWriter

This commit creates a builder for the StaxEventItemWriter

Resolves BATCH-2573

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

@@ -80,13 +80,13 @@ ResourceAwareItemWriterItemStream<T>, InitializingBean {
 	private static final Log log = LogFactory.getLog(StaxEventItemWriter.class);
 
 	// default encoding
-	private static final String DEFAULT_ENCODING = "UTF-8";
+	public static final String DEFAULT_ENCODING = "UTF-8";
 
 	// default encoding
-	private static final String DEFAULT_XML_VERSION = "1.0";
+	public static final String DEFAULT_XML_VERSION = "1.0";
 
 	// default root tag name
-	private static final String DEFAULT_ROOT_TAG_NAME = "root";
+	public static final String DEFAULT_ROOT_TAG_NAME = "root";
 
 	// restart data property name
 	private static final String RESTART_DATA_NAME = "position";

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

@@ -0,0 +1,285 @@
+/*
+ * Copyright 2017 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
+ *
+ *      http://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.xml.builder;
+
+import java.util.Map;
+
+import org.springframework.batch.item.xml.StaxEventItemWriter;
+import org.springframework.batch.item.xml.StaxWriterCallback;
+import org.springframework.core.io.Resource;
+import org.springframework.oxm.Marshaller;
+import org.springframework.util.Assert;
+
+/**
+ * A builder for the {@link StaxEventItemWriter}.
+ *
+ * @author Michael Minella
+ * @since 4.0
+ * @see StaxEventItemWriter
+ */
+public class StaxEventItemWriterBuilder<T> {
+
+	private Resource resource;
+
+	private Marshaller marshaller;
+
+	private StaxWriterCallback headerCallback;
+
+	private StaxWriterCallback footerCallback;
+
+	private boolean transactional = true;
+
+	private boolean forceSync = false;
+
+	private boolean shouldDeleteIfEmpty = false;
+
+	private String encoding = StaxEventItemWriter.DEFAULT_ENCODING;
+
+	private String version = StaxEventItemWriter.DEFAULT_XML_VERSION;
+
+	private String rootTagName = StaxEventItemWriter.DEFAULT_ROOT_TAG_NAME;
+
+	private Map<String, String> rootElementAttributes;
+
+	private boolean overwriteOutput = true;
+
+	private boolean saveState = true;
+
+	private String name;
+
+	/**
+	 * The name used to calculate the key within the
+	 * {@link org.springframework.batch.item.ExecutionContext}.  Required if
+	 * {@link StaxEventItemWriterBuilder#saveState(boolean)} is set to true.
+	 *
+	 * @param name name of the reader instance
+	 * @return The current instance of the builder.
+	 * @see StaxEventItemWriter#setName(String)
+	 */
+	public StaxEventItemWriterBuilder<T> name(String name) {
+		this.name = name;
+
+		return this;
+	}
+
+	/**
+	 * The {@link Resource} to be used as output.
+	 *
+	 * @param resource the output from the writer
+	 * @return the current instance of the builder.
+	 * @see StaxEventItemWriter#setResource(Resource)
+	 */
+	public StaxEventItemWriterBuilder<T> resource(Resource resource) {
+		this.resource = resource;
+
+		return this;
+	}
+
+	/**
+	 * The {@link Marshaller} implementation responsible for the serialization of the
+	 * items to XML.  This field is required.
+	 *
+	 * @param marshaller the component used to generate XML
+	 * @return the current instance of the builder.
+	 * @see StaxEventItemWriter#setMarshaller(Marshaller)
+	 */
+	public StaxEventItemWriterBuilder<T> marshaller(Marshaller marshaller) {
+		this.marshaller = marshaller;
+
+		return this;
+	}
+
+	/**
+	 * A {@link StaxWriterCallback} to provide any header elements
+	 *
+	 * @param headerCallback a {@link StaxWriterCallback}
+	 * @return the current instance of the builder.
+	 * @see StaxEventItemWriter#setHeaderCallback(StaxWriterCallback)
+	 */
+	public StaxEventItemWriterBuilder<T> headerCallback(StaxWriterCallback headerCallback) {
+		this.headerCallback = headerCallback;
+
+		return this;
+	}
+
+	/**
+	 * A {@link StaxWriterCallback} to provide any footer elements
+	 *
+	 * @param footerCallback a {@link StaxWriterCallback}
+	 * @return the current instance of the builder.
+	 * @see StaxEventItemWriter#setFooterCallback(StaxWriterCallback)
+	 */
+	public StaxEventItemWriterBuilder<T> footerCallback(StaxWriterCallback footerCallback) {
+		this.footerCallback = footerCallback;
+
+		return this;
+	}
+
+	/**
+	 * The resulting writer is participating in a transaction and writes should be delayed
+	 * as late as possible.
+	 *
+	 * @param transactional indicates that the writer is transactional.  Defaults to false.
+	 * @return the current instance of the builder
+	 * @see StaxEventItemWriter#setTransactional(boolean)
+	 */
+	public StaxEventItemWriterBuilder<T> transactional(boolean transactional) {
+		this.transactional = transactional;
+
+		return this;
+	}
+
+	/**
+	 * Flag to indicate that changes should be force-synced to disk on flush.
+	 *
+	 * @param forceSync indicates if force sync should occur.  Defaults to false.
+	 * @return the current instance of the builder
+	 * @see StaxEventItemWriter#setForceSync(boolean)
+	 */
+	public StaxEventItemWriterBuilder<T> forceSync(boolean forceSync) {
+		this.forceSync = forceSync;
+
+		return this;
+	}
+
+	/**
+	 * Flag to indicate that the output file should be deleted if no results were written
+	 * to it.  Defaults to false.
+	 *
+	 * @param shouldDelete indicator
+	 * @return the current instance of the builder
+	 * @see StaxEventItemWriter#setShouldDeleteIfEmpty(boolean)
+	 */
+	public StaxEventItemWriterBuilder<T> shouldDeleteIfEmpty(boolean shouldDelete) {
+		this.shouldDeleteIfEmpty = shouldDelete;
+
+		return this;
+	}
+
+	/**
+	 * Encoding for the file.  Defaults to UTF-8.
+	 *
+	 * @param encoding String encoding algorithm
+	 * @return the current instance of the builder
+	 * @see StaxEventItemWriter#setEncoding(String)
+	 */
+	public StaxEventItemWriterBuilder<T> encoding(String encoding) {
+		this.encoding = encoding;
+
+		return this;
+	}
+
+	/**
+	 * Version of XML to be generated.  Must be supported by the {@link Marshaller}
+	 * provided.
+	 *
+	 * @param version XML version
+	 * @return the current instance of the builder
+	 * @see StaxEventItemWriter#version
+	 */
+	public StaxEventItemWriterBuilder<T> version(String version) {
+		this.version = version;
+
+		return this;
+	}
+
+	/**
+	 * The name of the root tag for the output document.
+	 *
+	 * @param rootTagName tag name
+	 * @return the current instance of the builder
+	 * @see StaxEventItemWriter#setRootTagName(String)
+	 */
+	public StaxEventItemWriterBuilder<T> rootTagName(String rootTagName) {
+		this.rootTagName = rootTagName;
+
+		return this;
+	}
+
+	/**
+	 * A Map of attributes to be included in the document's root element.
+	 *
+	 * @param rootElementAttributes map fo attributes
+	 * @return the current instance of the builder.
+	 * @see StaxEventItemWriter#setRootElementAttributes(Map)
+	 */
+	public StaxEventItemWriterBuilder<T> rootElementAttributes(Map<String, String> rootElementAttributes) {
+		this.rootElementAttributes = rootElementAttributes;
+
+		return this;
+	}
+
+	/**
+	 * Indicates if an existing file should be overwritten if found. Defaults to true.
+	 *
+	 * @param overwriteOutput indicator
+	 * @return the current instance of the builder.
+	 * @see StaxEventItemWriter#setOverwriteOutput(boolean)
+	 */
+	public StaxEventItemWriterBuilder<T> overwriteOutput(boolean overwriteOutput) {
+		this.overwriteOutput = overwriteOutput;
+
+		return this;
+	}
+
+	/**
+	 * Indicates if the state of the writer should be saved in the
+	 * {@link org.springframework.batch.item.ExecutionContext}.  Setting this to false
+	 * will impact restartability.  Defaults to true.
+	 *
+	 * @param saveState indicator
+	 * @return the current instance of the builder
+	 * @see StaxEventItemWriter#setSaveState(boolean)
+	 */
+	public StaxEventItemWriterBuilder<T> saveState(boolean saveState) {
+		this.saveState = saveState;
+
+		return this;
+	}
+
+	/**
+	 * Returns a configured {@link StaxEventItemWriter}
+	 *
+	 * @return a StaxEventItemWriter
+	 */
+	public StaxEventItemWriter<T> build() {
+		Assert.notNull(this.marshaller, "A marshaller is required");
+
+		if(this.saveState) {
+			Assert.notNull(this.name, "A name is required");
+		}
+
+		StaxEventItemWriter<T> writer = new StaxEventItemWriter<>();
+
+		writer.setEncoding(this.encoding);
+		writer.setFooterCallback(this.footerCallback);
+		writer.setForceSync(this.forceSync);
+		writer.setHeaderCallback(this.headerCallback);
+		writer.setMarshaller(this.marshaller);
+		writer.setOverwriteOutput(this.overwriteOutput);
+		writer.setResource(this.resource);
+		writer.setRootElementAttributes(this.rootElementAttributes);
+		writer.setRootTagName(this.rootTagName);
+		writer.setSaveState(this.saveState);
+		writer.setShouldDeleteIfEmpty(this.shouldDeleteIfEmpty);
+		writer.setTransactional(this.transactional);
+		writer.setVersion(this.version);
+		writer.setName(this.name);
+
+		return writer;
+	}
+
+ }