Consider adding new KiwiMediaTypes utility class

[sleberknight]

The JAX-RS MediaType is a class, not an enum, so instances must be compared using equals and not ==. So, this is not valid:

var mediaType = response.getMediaType();
if (mediaType == MediaType.APPLICATION_XML_TYPE || mediaType == MediaType.TEXT_XML_TYPE) {
  ...
}

this is what you need to to instead:

var mediaType = response.getMediaType();
if (MediaType.APPLICATION_XML_TYPE.equals(mediaType) || MediaType.TEXT_XML_TYPE.equals(mediaType)) {
  ...
}

But this brings up another point, which is that it would be useful to have methods like isXml(MediaType) and isXml(String) that can handle either of the possible XML types. Other useful methods would be isJson, isPlainText, isHtml, and so on.

We would also need to research whether there are any things that could mess all this up, e.g. the various parameters that can be tacked on to media types such as text/html; charset=UTF-8. The JAX-RS MediaType#equals takes into account the type, subtype, and parameters. Thus text/html does not equal text/html; charset=UTF-8.

We could have different variations that either include or don't include the parameters. Normally, I'd want to just see if something is text/xml (or application/xml) to determine if it's XML content and ignore the parameters. So you could have:

// These two only compare the type and subtype, not the parameters
public static boolean isXml(MediaType mediaType) { ... }
public static boolean isXml(String mediaType) { ... }

// And these two perform a strict comparison of type, subtype, and parameters
public static boolean isXmlStrict(MediaType mediaType) { ... }
public static boolean isXmlStrict(String mediaType) { ... }

In all of the above proposed methods, both text/xml and application/xml are both considered XML.

See Mozilla's MIME types for more information.

[sleberknight]

To support the above methods, can start with some base methods, e.g.

// Compares only type and subtype
public static boolean areEqual(String mediaType1, String mediaType2) { ... }
public static boolean areEqual(MediaType mediaType1, MediaType mediaType2) { ... }

Could also include "supporting" methods to check if the type matches, if the subtype matches, etc. e.g.

public static boolean matchesType(MediaType mediaType, String typeToMatch) { ... }
public static boolean matchesSubtype(MediaType mediaType, String subtypeToMatch) { ... }

Might also want to include methods like this one

[sleberknight]

The "strict" methods don't make sense after looking at this again, because the parameters are just additional information, e.g. text/xml; charset=UTF-8 so there is nothing to "compare" them against.

The "areEqual" methods as well as the "matchesType" and "matchesSubtype" do make sense, because they are comparing two media types, e.g.

var mediaType = response.getMediaType();
var typeMatches = matchesType(mediaType, "text");
var subtypeMatches = matchesSubtype(mediaType, "xml");

[sleberknight]

These media type utilities are being added first to kiwi-beta in Add media type utilities

They can be migrated into kiwi later if we decide we like them enough.

[sleberknight]

I am marking this discussed as Closed since it is now in kiwi-beta and may be moved to kiwi at some point.