On Wed, Mar 11, 2009 at 09:47:26AM -0600, Andrew Ochsner wrote:
> So, just a quick follow up while I was reading this...
>
> { "items" : [{"field1":"one", "field2:"two"}, {"field1":"one",
> "field2:"two"}] }
>
> is the format I absolutely need. XML is just nice to have, but I need JSON
> in this format...
OK, thanks for clarification, please see the other response.
~Jakub
>
> On Wed, Mar 11, 2009 at 9:39 AM, Andrew Ochsner <aochsner_at_cs.stanford.edu>wrote:
>
> > Okay, here's ideally the scenario I have/want:
> >
> > I need JSON in a particular format where it looks like the following:
> > { "items" : [{"field1":"one", "field2:"two"}, {"field1":"one",
> > "field2:"two"}] }
> > or { "items" : [] } when the list is empty
> >
> > I'm not too particular about the XML output as we don't have any
> > requirements for it, just is a nice bonus for taking this approach, but I'll
> > include them as well:
> > <response>
> > <item><field1>one</field1><field2>two</field2></item>
> > <item><field1>one</field1><field2>two</field2></item>
> > </response>
> >
> > and
> >
> > <response/> for empty list
> >
> > Our class looks like:
> > @XmlRootElement(name = "response")
> > public class Items {
> > @XmlElement(name = "items")
> > public List<Item> items= new ArrayList<Item>();
> > }
> >
> > This works for when the list has 1 or more items, but returns "null" when
> > the list has 0 items (instead of { "items": [] })
> >
> > This makes sense though when you look at the XML being produced (which is
> > what the JSON is based off of). I really probably would want the XML to
> > look more like:
> > <response>
> > <items>
> > <item><field1>one</field1><field2>two</field2></item>
> > <item><field1>one</field1><field2>two</field2></item>
> > </items>
> > </response>
> >
> > and
> >
> > <response><items/></response>
> >
> > So, a simple change to the class:
> > @XmlElement(name = "items")
> > public List<Item> items= new ArrayList<Item>();
> >
> > becomes
> >
> > @XmlElementWrapper(name = "items")
> > public List<Item> items= new ArrayList<Item>();
> >
> > However, the JSON becomes:
> >
> > { "items" : [{ "item" : {"field1":"one", "field2:"two"}}, { "item" :
> > {"field1":"one", "field2:"two"}}] }
> > or { "items" : [ null ] } when the list is empty
> >
> > So it seems there are a few approaches I could take:
> > 1) Add a null Item when the list is empty in order to produce some XML -
> > not ideal
> > 2) Enable more than just root unwrapping in the XmlElementWrapper case
> > where I can unwrap the items in the list - sounds better
> > 3) Try the JacksonProvider and separate JSON generation from XML
> > generation... not considered this before this email...
> >
> > Does that make any sense? Thoughts?
> > Andy O
> >
> >
> > On Wed, Mar 11, 2009 at 5:10 AM, Jakub Podlesak <Jakub.Podlesak_at_sun.com>wrote:
> >
> >> On Tue, Mar 10, 2009 at 01:45:11PM -0600, Andrew Ochsner wrote:
> >> > Sorry, one more unfortunate update.
> >> >
> >> > Using XmlElementWrapper, while gets us closer to correct JSON (and looks
> >> to
> >> > be correct XML) it really messes things up for us in JSON when there are
> >> > elements in the array where it looks like :
> >> > { "items": { "item": {}, "item":{} }
> >>
> >> I suppose the issue now lays in the Item bean,
> >> since it's content is not being written.
> >>
> >> How the XML looks like?
> >>
> >> Could you give a quick try with something like:
> >>
> >> @XmlRootElement
> >> public class Item {
> >>
> >> public String field1 = "one";
> >> public String field2 = "two";
> >> }
> >>
> >> And second thing: the JSON above is incorrect, you should not have
> >> two "item" objects encapsulated in the same container object,
> >> how did you get it? Default mapped convention?
> >>
> >> And i am also a bit confused with your desired JSON format, since
> >>
> >> {"items":[{"field1":"val1","field2":"val2"}] differs from
> >> {"items":[{"item":{"field1":"val1","field2":"val2"}}]
> >>
> >> Could you please clarify? I mean, could you give us some examples
> >> of JSON exprs you need to get generated?
> >>
> >> And the last thing: If i understand it correctly: you do need both XML and
> >> JSON generated, right?
> >>
> >> Thanks,
> >>
> >> ~Jakub
> >>
> >>
> >>
> >> >
> >> > So, we really have an issue here. And the hack solution really defeats
> >> the
> >> > purpose for us as we want to generate documentation based on the code
> >> (as
> >> > opposed to javadoc which can and will get out of sync). We can't infer
> >> much
> >> > from a Response return value.
> >> >
> >> > Thanks
> >> > Andy O
> >> >
> >> > On Tue, Mar 10, 2009 at 10:20 AM, Moiz Dohadwala <
> >> mdohadwala_at_mokafive.com>wrote:
> >> >
> >> > > Hello,
> >> > >
> >> > >
> >> > >
> >> > > Thank you all for your suggestions. I had tried out the annotations
> >> > > suggested below without success prior to posting to the mailing list.
> >> Right
> >> > > now, due to time pressure, I have implemented the following ugly hack:
> >> > >
> >> > >
> >> > >
> >> > > If( rows.getTotalCount() == 0 )
> >> > >
> >> > > {
> >> > >
> >> > > return Response.ok(“{rows:[], totalCount:0}”).build();
> >> > >
> >> > > else
> >> > >
> >> > > {
> >> > >
> >> > > return Response.ok(rows).build();
> >> > >
> >> > > }
> >> > >
> >> > >
> >> > >
> >> > > This seems to have tied me over for now.
> >> > >
> >> > >
> >> > >
> >> > > I would suggest changes to the JSONConfiguration.arrays() api to
> >> specify
> >> > > forcing of the empty arrays.
> >> > >
> >> > >
> >> > >
> >> > > -Moiz
> >> > >
> >> > >
> >> > >
> >> > > *From:* aochsner_at_gmail.com [mailto:aochsner_at_gmail.com] *On Behalf Of
> >> *Andrew
> >> > > Ochsner
> >> > > *Sent:* Tuesday, March 10, 2009 8:49 AM
> >> > > *To:* users_at_jersey.dev.java.net
> >> > > *Subject:* Re: [Jersey] RE: array handling in JAXB to JSON conversion
> >> > >
> >> > >
> >> > >
> >> > > So, a little update because I'm running into the same issue, except
> >> I'm
> >> > > using the natural mapping.
> >> > >
> >> > >
> >> > > Various combinations of required=true/false and nillable = true/false
> >> have
> >> > > not helped. In fact, when getting as XML, the <items/> element is not
> >> > > getting written out. So that's a JAXB thing.
> >> > >
> >> > > So I'm trying the XmlElementWrapper, and it's close. The XML does
> >> spit out
> >> > > <items/> which is good, but the JSON is { "items":[null] } which
> >> doesn't
> >> > > seem to be the same as { "items":[] } which is what I want.
> >> > >
> >> > > HTH
> >> > > Andy O
> >> > >
> >> > > On Mon, Mar 9, 2009 at 10:39 AM, Jakub Podlesak <
> >> Jakub.Podlesak_at_sun.com>
> >> > > wrote:
> >> > >
> >> > > On Mon, Mar 09, 2009 at 05:10:19PM +0100, Paul Sandoz wrote:
> >> > > > Hi Jakub,
> >> > > >
> >> > > > Do you mean that JAXB is not writing out any start element for
> >> "items"
> >> > > > because the value of the items field is null or empty?
> >> > >
> >> > > Hmmm, you are right, jaxb should generate at least <items/>, which
> >> should
> >> > > IIRC get
> >> > > translated into "items":null for the default mapped convention.
> >> > >
> >> > > Need to check this out, and then will report back here.
> >> > >
> >> > > ~Jakub
> >> > >
> >> > >
> >> > >
> >> > > >
> >> > > > There may be an annotation to force JAXB to always write out
> >> "items":
> >> > > >
> >> > > > 1) using c; or
> >> > >
> >> > > >
> >> > > > 1) using XmlElementWrapper, the JavaDoc states:
> >> > > >
> >> > > >
> >> > >
> >> http://java.sun.com/javase/6/docs/api/javax/xml/bind/annotation/XmlElementWrapper.html
> >> > > > The two serialized XML forms allow a null collection to be
> >> represented
> >> > > > either by absence or presence of an
> >> > > > element with a nillable attribute.
> >> > > >
> >> > > > or it may be possible to utilize XmlJavaTypeAdapter.
> >> > > >
> >> > > > Paul.
> >> > > >
> >> > > > On Mar 9, 2009, at 4:47 PM, Jakub Podlesak wrote:
> >> > > >
> >> > > >>
> >> > > >> Hi Moiz,
> >> > > >>
> >> > > >> You have hit an edge case, and i am afraid i have no good news for
> >> you.
> >> > > >> Jersey JSON provider takes what JAXB gives out, and the information
> >> > > >> about the emtpy array is obviously missing.
> >> > > >>
> >> > > >> One option would be to try out the provider mentioned by Tatu.
> >> > > >> Have you had a chance to test it yet?
> >> > > >>
> >> > > >> Another option would be to use the low-level JSONObect/JSONArray
> >> > > >> providers (used in bookmark example [1].
> >> > > >>
> >> > > >> ~Jakub
> >> > > >>
> >> > > >> [1]
> >> > >
> >> http://download.java.net/maven/2/com/sun/jersey/samples/bookmark/1.0.3-SNAPSHOT/bookmark-1.0.3-SNAPSHOT-project.zip
> >> > > >>
> >> > > >>
> >> > > >> On Fri, Mar 06, 2009 at 07:21:51AM -0800, Moiz Dohadwala wrote:
> >> > > >>> I have tried that too, but hasn't worked either.
> >> > > >>>
> >> > > >>> -Moiz
> >> > > >>>
> >> > > >>> From: Wilhelmsen Tor Iver [mailto:TorIverW_at_arrive.no]
> >> > > >>> Sent: Friday, March 06, 2009 5:01 AM
> >> > > >>> To: users_at_jersey.dev.java.net
> >> > > >>> Subject: Re: [Jersey] RE: array handling in JAXB to JSON
> >> conversion
> >> > > >>>
> >> > > >>> Try adding required=true to this:
> >> > > >>>
> >> > > >>> @XmlElement(name="items")
> >> > > >>> List<Item> items;
> >> > > >>>
> >> > > >>> or else tell JAXB to treat nulls and empty collections
> >> differently. We
> >> > > >>> ran into the same issue where null/empty elements were absent from
> >> the
> >> > > >>> XML and thus a JAXB client would generate classes missing these
> >> > > >>> properties.
> >> > > >>
> >> > > >>
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> >> > > >
> >> > > >
> >> > > >
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> >> > >
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> >