Make empty tags configurable during serialization #640

Croway · 2024-02-19T14:53:16Z

No description provided.

cowtowncoder · 2024-02-19T19:13:15Z

src/main/java/com/fasterxml/jackson/dataformat/xml/deser/XmlTokenStream.java

@@ -559,6 +561,9 @@ private final String _collectUntilTag() throws XMLStreamException
            if (FromXmlParser.Feature.EMPTY_ELEMENT_AS_NULL.enabledIn(_formatFeatures)) {
                return null;
            }
+            if (FromXmlParser.Feature.EMPTY_ELEMENT_AS_EMPTY_ARRAY.enabledIn(_formatFeatures)) {
+                return JsonToken.START_ARRAY.asString() + JsonToken.END_ARRAY.asString();


I am not sure how this makes sense -- all we get here is String "[]", which won't be further decoded?

cowtowncoder · 2024-02-19T19:14:21Z

Ok, I can see what this PR does, but I am not quite sure how it makes any sense as a feature.

Croway · 2024-02-19T19:21:26Z

Ok, I can see what this PR does, but I am not quite sure how it makes any sense as a feature.

Hello, I have an usecase (mostly due to compatibility) that requires to have empty xml tags serialized as json empty array.
If you think this usecase does not make sense, could you suggest how to implement it? (custom Serializer?)

cowtowncoder · 2024-02-19T19:33:17Z

@Croway I think this is unfortunately bit too specific to add as a general on/off feature.

I suspect it would not be easy to implement as custom deserializer (but might be possible)

I would be open to configuration setting that allows configuring value to return as any String (so in your case, you could set it as "[]"). This would need to be configuration on XmlFactory (through XmlFactoryBuilder -- it has _nameForTextElement to kind of show how to do this I think).
Such general purpose functionality could be useful for other things too I suspect.

Croway · 2024-02-20T10:33:49Z

Thanks for the hint @cowtowncoder I have updated the PR.

src/main/java/com/fasterxml/jackson/dataformat/xml/XmlFactory.java

src/main/java/com/fasterxml/jackson/dataformat/xml/XmlMapper.java

src/main/java/com/fasterxml/jackson/dataformat/xml/deser/FromXmlParser.java

src/main/java/com/fasterxml/jackson/dataformat/xml/deser/XmlTokenStream.java

cowtowncoder · 2024-03-02T04:47:50Z

@Croway Ok I think this would work. Before merging, there is one small process part: we'd need CLA from: https://github.com/FasterXML/jackson/blob/master/contributor-agreement.pdf

this only needs to be done once, before the first contribution and is good all future contributions.

The usual way is to print, fill & sign, scan/photo, email to cla at fasterxml dot com.
And once I get it I can proceed.

Looking forward to merging this new feature!

Add EMPTY_ELEMENT_AS_EMPTY_ARRAY Feature

c11e8bc

cowtowncoder reviewed Feb 19, 2024

View reviewed changes

Make empty values configurable

371fda9