Do we have anything like @XMlPath in jackson? On Tuesday, September 12, 2017 at 3:58:58 PM UTC+5:30, chetan choulwar wrote: > > This actually sounds good to have one POJO defined for each of the input > JSON that is being dealt and that's what the way I was thinking but was not > able to map nested json elements to shallow (class level) pojo > properties(To avoid multiple POJOs for nested json objects). Well now that > I've this elastic library at hand I can have one POJO defined for each > input json and can use polymorphic deserialization then. > > Thanks a lot for your inputs Tatu..!:) > > On Tuesday, September 12, 2017 at 4:03:34 AM UTC+5:30, Tatu Saloranta > wrote: >> >> On Sun, Sep 10, 2017 at 12:19 PM, chetan choulwar <[email protected]> >> wrote: >> > Okay..Let me help you with one real time example. Consider for an >> example >> > different tv channels have exposed their APIs to get list of programs >> > telecast-ed on them. And now suppose I'm trying to expose one APIs that >> will >> > accept channel name and provide the list of programs for that >> particular >> > channel by calling it from my API and converting the response received >> in my >> > own format (a common one). The kind of data I'm getting from different >> APIs >> > is same but their representation is somewhat different, and what I want >> to >> > do is to convert these responses into a common format defined by my API >> and >> > send it as a response from my API. >> > So now that I'm sure that I'm dealing with same kinda data represented >> > somewhat different, is it okay to convert it into common format? >> >> Yes, but I don't think you should try to use just one single Java >> class for all of that. >> >> It makes sense to use one class for representing output to your users, >> but I think that if input structures, names vary, >> then POJOs to map them to should be different too. You may reuse some >> of those for "similar enough" inputs, >> but there are limits to how far this helps. >> I mean, you will always have to do some work anyway when adopting new >> inputs -- even if just adding annotations. >> So question there becomes: what approaches is easiest, most reliable >> to maintain? >> >> > Currently I'm doing this by mapping each of the responses to JsonNode >> only, >> > but every time I add a new common API I need to write different logic >> to >> > convert the new response into a common one and that to for different >> APIs >> > I'm calling from my API. >> > If any kinda JSON response can be mapped to JsonNode, isn't is possible >> to >> > map these different responses to any particular format? I mean can I >> write >> > my resource object in such a way that I'd be able to map these >> different >> > json responses representing same kinda data to my own resource, in some >> way, >> > instead of doing manually by traversing through json tree? >> > >> > Hope it is clear to now..Initially I thought it's impossible, but you >> gave >> > me direction and I do believe now there'd be some way that I can bind >> these >> > different resources to common one. May be the way json objects are >> mapped to >> > JsonNode. >> > >> > Please let me know if this is clear to you, as right now you the only >> hope I >> > can see.! >> > >> > Thank you Tatu..! >> >> It may make sense to map input you get into `JsonNode` and have >> separate code to traverse them; >> or to have a set of Input POJOs and code to convert from those to >> result/output POJO. >> There are pros and cons to each approach. >> >> -+ Tatu +- >> >> > >> > On Sunday, September 10, 2017 at 10:00:21 PM UTC+5:30, Tatu Saloranta >> wrote: >> >> >> >> On Sat, Sep 9, 2017 at 9:58 PM, chetan choulwar <[email protected]> >> >> wrote: >> >> > That @JsonAlias worked fine. But my problem is with nested elements, >> how >> >> > can >> >> > I specify nested json element into alias? >> >> >> >> You can't. If your structures differ beond just naming you need to do >> >> something else. >> >> Databinding is meant to match incoming document structure to a Java >> >> object graph and vice versa. >> >> It is not designed to allow arbitrary transformation, or unification >> >> of differing structures into single model. >> >> >> >> It is possible to unify differing structures, of course, but that is >> >> true transformation and something explicitly >> >> out of scope for Jackson. You can use `JsonNode` as structure modify, >> >> for input and output structures, and it is possible >> >> to change structure any way you want. But you have to write that >> >> transformation yourself. >> >> Or you can use separate Java classes for input(s) and output. >> >> >> >> > And reason for doing so is that I'm writing an API that will send >> the >> >> > common >> >> > response out of all these different APIs I am calling from my API. >> >> >> >> I am still not sure I fully understand your usage, still; this is very >> >> generic explanation. >> >> >> >> But assuming I do understand... if input data you get from a service >> >> differs, you should consider separating handling of your input from >> >> constructing your output. Do not try to use same set of objects if >> >> structures are not same or similar enough. Trying to do that is false >> >> savings and tends to sacrifice clean design for seeming savings. >> >> >> >> This assuming I actually understood what you are trying to do -- >> >> without full explanation of steps from calling another service to >> >> formulating output it is possible to misunderstand intent. >> >> >> >> > Apart from this it'd be great if you can you mail me a link where I >> can >> >> > find >> >> > latest documentation and hands-on for the same. >> >> > >> >> > Thanking you in anticipation..! >> >> >> >> Documentation hub is at: >> >> >> >> https://github.com/FasterXML/jackson-docs >> >> >> >> and main portal >> >> >> >> https://github.com/FasterXML/jackson/ >> >> >> >> has some links. >> >> >> >> -+ Tatu +- >> >> >> >> >> >> >> >> > >> >> > >> >> > On Sunday, September 10, 2017 at 9:21:55 AM UTC+5:30, Tatu Saloranta >> >> > wrote: >> >> >> >> >> >> On Fri, Sep 8, 2017 at 5:13 AM, chetan choulwar <[email protected]> >> >> >> >> wrote: >> >> >> > Thanks a lot for your input. I tried it and it worked as >> expected. >> >> >> > But >> >> >> > I'm >> >> >> > stuck at a situation where I want to retrieve a value from nested >> >> >> > block, >> >> >> > so >> >> >> > can you help me out? >> >> >> > For example, >> >> >> > By calling REST API "https://xyz.com/resources/resource"; gives >> me { >> >> >> > >> >> >> > "value"={"name":"abc.txt"} >> >> >> > >> >> >> > } >> >> >> > and calling "https://abc.com/resources/resource"; gives me >> >> >> > {"title":"idontknow.txt"} >> >> >> > now how can I take name out from the first json response? >> >> >> > >> >> >> > Once again thanks a lot for your answer..!:) >> >> >> >> >> >> I am not sure why my first answer wouldn't work here. All you are >> >> >> doing is specifying that property name in json is an alias that can >> be >> >> >> used for property in POJO, so you would access it with field name >> (or >> >> >> getter) you have. >> >> >> >> >> >> But at the same time if these are effectively different objects it >> is >> >> >> unclear why same Java class should be used anyway -- perhaps they >> >> >> should use different POJOs. >> >> >> >> >> >> -+ Tatu +- >> >> >> >> >> >> >> >> >> > >> >> >> > On Friday, September 8, 2017 at 9:19:49 AM UTC+5:30, Tatu >> Saloranta >> >> >> > wrote: >> >> >> >> >> >> >> >> On Thu, Sep 7, 2017 at 5:24 AM, chetan choulwar < >> [email protected]> >> >> >> >> wrote: >> >> >> >> > Hi All, >> >> >> >> > >> >> >> >> > I'm calling different REST APIs and getting different kinda >> JSON >> >> >> >> > responses; >> >> >> >> > is there any way to pick particular attribute from different >> JSON >> >> >> >> > responses >> >> >> >> > and map it to a one common property of defined POJO (Resource >> for >> >> >> >> > my >> >> >> >> > API) >> >> >> >> > that can then be sent as a response from the REST API that >> I've >> >> >> >> > exposed? >> >> >> >> > >> >> >> >> > For Example: >> >> >> >> > By calling REST API "https://xyz.com/resources/resource"; >> gives me >> >> >> >> > {"name":"abc.txt"} >> >> >> >> > and calling "https://abc.com/resources/resource"; gives me >> >> >> >> > {"title":"idontknow.txt"} >> >> >> >> > >> >> >> >> > And I have one resource class defined for my APIs to return >> i.e. >> >> >> >> > MyResource >> >> >> >> > { >> >> >> >> > String fileName; >> >> >> >> > } >> >> >> >> > >> >> >> >> > So is there any way that I can map "name"/"title" to fileName >> i.e. >> >> >> >> > how >> >> >> >> > can I >> >> >> >> > use jackson to deserialize these jsons to MyResource type? >> >> >> >> > >> >> >> >> > Please let me know if this is valid? and if yes, how? >> >> >> >> >> >> >> >> If you have many different names to use, it may be simpler to >> just >> >> >> >> bind JSON to `Map` or `JsonNode`, and extract value explicitly. >> >> >> >> >> >> >> >> But if there are just couple of values, you can use `@JsonAlias` >> >> >> >> like: >> >> >> >> >> >> >> >> public class POJO { >> >> >> >> @JsonAlias({ "name", "title" }) >> >> >> >> public String fileName; >> >> >> >> } >> >> >> >> >> >> >> >> which would then accept alternate names "name" and "title", but >> >> >> >> serialize as "fileName" (which it also accepts). >> >> >> >> This annotations was added in Jackson 2.9 >> >> >> >> >> >> >> >> -+ Tatu +- >> >> >> > >> >> >> > -- >> >> >> > You received this message because you are subscribed to the >> Google >> >> >> > Groups >> >> >> > "jackson-dev" group. >> >> >> > To unsubscribe from this group and stop receiving emails from it, >> >> >> > send >> >> >> > an >> >> >> > email to [email protected]. >> >> >> > For more options, visit https://groups.google.com/d/optout. >> >> > >> >> > -- >> >> > You received this message because you are subscribed to the Google >> >> > Groups >> >> > "jackson-dev" group. >> >> > To unsubscribe from this group and stop receiving emails from it, >> send >> >> > an >> >> > email to [email protected]. >> >> > For more options, visit https://groups.google.com/d/optout. >> > >> > -- >> > You received this message because you are subscribed to the Google >> Groups >> > "jackson-dev" group. >> > To unsubscribe from this group and stop receiving emails from it, send >> an >> > email to [email protected]. >> > For more options, visit https://groups.google.com/d/optout. >> >
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