Restlet/Jackson JSON wrapper for ArrayList<Profile>

Question

i'm using the Restlet library for a WS server and i've recently switched from XStream/Jettison to Jackson as a JSON serializer/deserializer because of some issues.

A first drawback is that my ArrayList< Profile > (previously a Vector with Jettison) it doesn't wrap the list of Profiles when serialized and the JSON instead of "Profile:[{firstProfile}, {secondProfile}]" it looks like: [{firstProfile}, {secondProfile}]

I can overcome to this issue in the client telling manually which is the correct mapping but i would prefer to use a KVC approach.

I've looked around and it seems that it's a known issue: http://wiki.fasterxml.com/JacksonPolymorphicDeserialization (5.1 Missing type information on Serialization) that it suggest to:

• Use arrays instead of Lists
• Sub-class list, using class MyPojoList extends ArrayList { }
• Force use of specific root type

the simplest way it should be to return an "Profile[] profile" array but it seems not working, before trying the other solutions i've rechecked around and it seems that you can use a @XmlRootElement(name = "Profile") to wrap the JSON root element: http://jira.codehaus.org/browse/JACKSON-163?focusedCommentId=213588&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-213588

so for using JAXB annotations with Jackson you need to configure the objectMapper: http://wiki.fasterxml.com/JacksonJAXBAnnotations

but in restlet to do so you need to override createObjectMapper to pass a Custom converter (see: http://restlet-discuss.1400322.n2.nabble.com/Set-custom-objectMapper-to-Jackson-Extension-td6287812.html and http://restlet-discuss.1400322.n2.nabble.com/Jackson-Mix-in-Annotations-td6211060.html#a6231831 )

this is what i'm trying now! the question is there a more straightforward way to achieve this??

Thanks!!

Answer 1

the solution for me is to annotate the Profile class with:

@JsonTypeInfo(use=JsonTypeInfo.Id.NAME, include=JsonTypeInfo.As.WRAPPER_OBJECT)
public class Profile extends Element implements Serializable {

and now the json now looks like:

{"Profile":{ ... }}

and the return type is a Sub-classed list:

public class ProfileList extends ArrayList<Profile>
{}

see http://wiki.fasterxml.com/JacksonPolymorphicDeserialization 5.1

Answer 2

I think what you want is not really available in a sense that JAX-B seems to have some rules on how to deal with lists. See this converstation on the RESTeasy mailing list