On Fri, Dec 21, 2018 at 2:30 PM matt Smith <matt.smith.11...@gmail.com> wrote:
>
> In the above case, I called `mapper.writeValueAsString(wrapper.getFoo());`
>
> I changed to the following (moved to annotation to the field level). when I
> write using `mapper.writeValueAsString(wrapper)`, I see the expected
> serialization applied. However, extra node "foo" is added at root. is there a
> way to not have it?
No, if applied as content serializer, Map serializer will produce wrapping.
You would need custom serializer that just serializes entries and not
enclose them within START_OBJECT / END_OBJECT.
-+ Tatu +-
> public class Wrapper {
>
>
> @JsonSerialize(contentUsing = ItemRowSerializer.class)
> private Map<RecordDomain, ItemRow> foo;
>
>
> public Wrapper(Map<RecordDomain, ItemRow> fooz) {
> foo = new HashMap<>(fooz);
> }
>
>
> public Map<RecordDomain, ItemRow> getFoo() {
> return foo;
> }
>
>
> public void setFoo(Map<RecordDomain, ItemRow> foo) {
> this.foo = foo;
> }
> }
>
>
> On Friday, December 21, 2018 at 1:52:41 PM UTC-8, matt Smith wrote:
>>
>> even moving annotation to the field did not work.
>> Note I have annotated class ItemRow class which ofcourse i can't since it is
>> part of legacy code.
>>
>> On Friday, December 21, 2018 at 12:49:21 PM UTC-8, Tatu Saloranta wrote:
>>>
>>> On Fri, Dec 21, 2018 at 12:06 AM matt Smith <matt.smi...@gmail.com> wrote:
>>> >
>>> > so I have made this wrapper and annotated getter with @JsonSerialize.
>>> > however, I do not see it being applied. what is wrong here?
>>>
>>> That looks like it should work. If not, a unit test & issue would make
>>> sense.
>>>
>>> -+ Tatu +-
>>>
>>> >
>>> > public class Wrapper {
>>> >
>>> >
>>> > private Map<RecordDomain, ItemRow> foo;
>>> >
>>> >
>>> > public Wrapper(Map<RecordDomain, ItemRow> fooz) {
>>> > foo = new HashMap<>(fooz);
>>> > }
>>> >
>>> >
>>> > @JsonSerialize( contentUsing = ItemRowSerializer.class)
>>> > public Map<RecordDomain, ItemRow> getFoo() {
>>> > return foo;
>>> > }
>>> >
>>> >
>>> > public void setFoo(Map<RecordDomain, ItemRow> foo) {
>>> > this.foo = foo;
>>> > }
>>> > }
>>> >
>>> >
>>> > On Thursday, December 20, 2018 at 1:25:59 PM UTC-8, Tatu Saloranta wrote:
>>> >>
>>> >> On Thu, Dec 20, 2018 at 11:22 AM matt Smith <matt.smi...@gmail.com>
>>> >> wrote:
>>> >> >
>>> >> > I encountered a case where class level JsonSerializable annotation
>>> >> > does not require registration with Simple Module but method level
>>> >> > does.
>>> >>
>>> >> Hmmh. This seems odd, let's see.
>>> >>
>>> >> > Here is the example I tried
>>> >> >
>>> >> > @JsonSerialize(using = ItemRowSerializer.class )
>>> >> > private ItemRow tes
>>> >> > tItem(){
>>> >> > return new ItemRow("abc", Arrays.asList("item1", "item2",
>>> >> > "item3"));
>>> >> > }
>>> >> >
>>> >> >
>>> >> > I test it out like this
>>> >> >
>>> >> >
>>> >> > String jsonResult = new ObjectMapper().writeValueAsString(testItem());
>>> >> > System.out.println(jsonResult);
>>> >> >
>>> >> > I noticed that jsonString did not serialize using ItemRowSerializer.
>>> >>
>>> >> Ah. No, it won't. Jackson does not see you calling the method; Jackson
>>> >> sees the object you pass, which was returned by the method. There is
>>> >> no linkage there: Jackson can only introspects classes you pass to it.
>>> >>
>>> >> > However, when I did this, it gave the expected jsonString
>>> >> >
>>> >> >
>>> >> > SimpleModule module = new SimpleModule()
>>> >> > module.addSerializer(ItemRowSerializer.class)
>>> >> > mapper.register(module);
>>> >> > String jsonResult = new
>>> >> > ObjectMapper().writeValueAsString(testItem());
>>> >> > System.out.println(jsonResult);
>>> >> >
>>> >> >
>>> >> > On the otherhand, if I had my ItemRow class annoated with
>>> >> > @JsonSerializable, there was no need with module at all.
>>> >>
>>> >> I think you mean `@JsonSerialize` here (there is interface type
>>> >> `JsonSerializable`, but no annotation).
>>> >>
>>> >> > i.e
>>> >> >
>>> >> > @JsonSerializable(using = ItemRowSerailizer
>>> >> > public class ItemRow<T> {...}
>>> >> >
>>> >> >
>>> >> > Since I am passing this serialized object over the wire, I do not
>>> >> > prefer to write to mapper and send string representation across.
>>> >> >
>>> >> > how would I go about getting method level annotation working without
>>> >> > module registration?
>>> >>
>>> >> Method level annotations only work when property is accessed via
>>> >> method (or field) in question.
>>> >>
>>> >> So if you had something like:
>>> >>
>>> >> public class Rows
>>> >> @JsonSerialize(using = .... )
>>> >> public ItemRow<Type> getRows() { ... }
>>> >> }
>>> >>
>>> >> and serialized an instance of `Rows`, serializer would be found. But
>>> >> for root values, there is no such reference.
>>> >>
>>> >> On related note, I strongly recommend always using a wrapper type
>>> >> around generic values, so that root value is never of generic type.
>>> >> Reason for this is that Java Type Erasure will often cause problems if
>>> >> attempting to pass an instance of generic type -- so Jackson can not
>>> >> detect intended type (all it sees is type variable from class
>>> >> declaration).
>>> >>
>>> >> So, attempts to serialize, say, Row<T>, will be seen as `Row<?>`, and
>>> >> possibly (although not always) cause issues in finding handlers for
>>> >> the type -- for example, if value type has annotations, they may not
>>> >> be visible.
>>> >>
>>> >> -+ Tatu +-
>>> >
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