Add setter for "standalone" attribute in StaxEventItemWriter

[spring-projects-issues]

Mahmoud Ben Hassine opened BATCH-2856 and commented

As of v4.2.0, the only way to add the standalone attribute in the XML declaration of the output file of StaxEventItemWriter is to extend the writer and override startDocument (as stated in its javadoc). Here is an example:

@Bean
public StaxEventItemWriter<Person> itemWriter() {
    StaxEventItemWriter<Person> itemWriter = new StaxEventItemWriter<Person>() {
        @Override
        protected void startDocument(XMLEventWriter writer) throws XMLStreamException {
            writer.add(createXmlEventFactory().createStartDocument(DEFAULT_ENCODING, DEFAULT_XML_VERSION, true));
            writer.add(xmlEventFactory.createStartElement(getRootTagNamespacePrefix(), getRootTagNamespace(), getRootTagName()));
        }
    };
    // TODO set other properties on the writer
    return itemWriter;
}

The StaxEventItemWriter provides setters for the version and encoding attributes, but not for the standalone attribute. I believe it can also provide a setter for standalone as this will make it easier to customize the XML declaration rather than having to extend the writer and override startDocument (which is error prone BTW if we forget to add the root element as shown in the example above).

NB: The example shown above works with Java 9+, see https://bugs.openjdk.java.net/browse/JDK-8139584

---

Affects: 4.2.0

Reference URL: https://stackoverflow.com/questions/58714744/staxeventitemwriter-xml-header

[parikshitdutta]

Hi @mminella, just wanted to check with you, if you are active on this one, or I can give it a try.

Thank you.

[mminella]

Hi @parikshitdutta I assigned this to you as your requested. Let me know if you don't have time to work on it.

[parikshitdutta]

Thanks @mminella, I will take care of it.

[parikshitdutta]

Hi @mminella,
To complete this task, it seems, we need to upgrade stax2-api from 4.2 to 4.2.1, in our case woodstox-core from 6.2.0 to 6.2.1

Reason:
stax2-api-4.2 ignores standalone attribute completely, check here:
https://github.com/FasterXML/stax2-api/blob/1bcbcf1e81a9820adfe45acbee94ae65187c72f7/src/main/java/org/codehaus/stax2/ri/Stax2EventWriterImpl.java#L84-L89

whereas, stax2-api-4.2.1 seems to fix this part, check here:
https://github.com/FasterXML/stax2-api/blob/8f10bb50124cb70048a3ec8dd2dca4421a04733c/src/main/java/org/codehaus/stax2/ri/Stax2EventWriterImpl.java#L84-L91

Thank you.

[parikshitdutta]

Hi @mminella,
Based on my observation mentioned here: #758 (comment) and only patch level upgrade required for woodstox-core, I thought it would be okay for me to update the build script.

Please have a look at PR #3764, I will look forward to your feedback.

Thank you.

[fmbenhassine]

Resolved with #3764 .