Re: [jackson-user] Using a converter only on root object/collection
On Mon, Feb 13, 2017 at 4:46 AM, Clément Poulain wrote:
> Hi Tatu, thanks for the reply.
>
> I wanted to avoid using a wrapper as my REST API is built on top of
> interfaces used for other things, and I would like to keep them untouched.
> I have a large number of calls returning any Collection (Set, List,
> UnmodifiableSet, etc.), so doing it purely on Jackson side would avoid
> modifying all of them. I found it to be elegant to properly separate
> business logic from serialization logic.
>
> I'm curious, why isn't BeanSerializerModifier.modifySerializer() called for
> Collection?
Because `modifyCollectionSerializer()` is called for it; they are type-specific.
-+ Tatu +-
>
> Thanks,
>
> On Tuesday, February 7, 2017 at 8:28:56 PM UTC+1, Tatu Saloranta wrote:
>>
>> There is no functionality to do it the way you suggested (although
>> immutability of classes is not a blocker, you could use mix-in
>> annotations).
>>
>> But wouldn't it be simpler to use a simple wrapper structure to get
>> structure match the output, instead of trying to change the whole
>> serialization logic to produce different structure than natural one?
>>
>> public class Wrapper {
>> public List items;
>>
>>public Wrapper(List l) { items = l; }
>>
>> public int getSize() { return items.size(); }
>> }
>>
>> That would produce output like what you are looking for.
>>
>> -+ Tatu +-
>>
>>
>>
>> On Tue, Feb 7, 2017 at 6:26 AM, Clément Poulain wrote:
>> > Hi there,
>> >
>> > I'm trying to implement pagination using Jersey and Jackson. I don't
>> > want to
>> > modify my API, so I would like the pagination to take place during
>> > serialization.
>> > To simplify, lets pretend I simply want to add the size of a collection
>> > when
>> > serializing it.
>> >
>> > The current output is:
>> >
>> > [
>> > {
>> > pojo1
>> > }, {
>> > pojo2
>> > }, {
>> > pojo3
>> > }
>> > ]
>> >
>> > What I try to get is:
>> >
>> > {
>> > size: 3,
>> > items: [
>> > {
>> > pojo1
>> > }, {
>> > pojo2
>> > }, {
>> > pojo3
>> > }
>> > ]
>> > }
>> >
>> > I don't have control on the collections I receive to serialize, so I
>> > cannot
>> > annotate a class like described in
>> > http://www.cowtowncoder.com/blog/archives/2013/10/entry_482.html.
>> >
>> > I tried to register a `BeanSerializerModifier` to my `ObjectMapper` but
>> > I
>> > have two issues:
>> >
>> > 1. it looks like collections (List, Set...) don't go through my modifier
>> >
>> > MAPPER.registerModule(new SimpleModule().setSerializerModifier(new
>> > BeanSerializerModifier() {
>> > @Override
>> > public JsonSerializer modifySerializer(SerializationConfig
>> > config,
>> > BeanDescription desc, JsonSerializer serializer) {
>> >
>> > System.out.println(desc.getBeanClass()); // <== prints "pojo",
>> > "int", "String" ... but never "Collection" or "Set" or "List" or...
>> >
>> > return serializer;
>> > }
>> > }));
>> >
>> >
>> > 2. (let's say we solve 1.) How to make sure this conversion occurs only
>> > for
>> > root collection and not for nested collections inside pojo?
>> > I'm asking because I tried also to use a `StdConverter` instead of a
>> > `BeanSerializerModifier`:
>> >
>> > MAPPER.registerModule(new SimpleModule()
>> > .addSerializer(Collection.class, new
>> > StdDelegatingSerializer(Collection.class,
>> > new StdConverter() {
>> > @Override
>> > public PaginationCollection convert(Collection value) {
>> > return new PaginationCollection(value);
>> > }
>> > }))
>> >
>> > It logically ends up into a `StackOverflowException` as
>> > `PaginationCollection` is also containing a `Collection` (for "items"),
>> > which in turn was converted to `PaginationCollection`, etc, etc.
>> > Even if the final solution does not involve a `Converter`, this will
>> > need to
>> > be handled properly.
>> >
>> > TL;DR: what is the best way to modify serialization for root collection
>> > only?
>> >
>> > Thanks!
>> >
>> > --
>> > You received this message because you are subscribed to the Google
>> > Groups
>> > "jackson-user" group.
>> > To unsubscribe from this group and stop receiving emails from it, send
>> > an
>> > email to jackson-user...@googlegroups.com.
>> > To post to this group, send email to jackso...@googlegroups.com.
>> > For more options, visit https://groups.google.com/d/optout.
>
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Re: [jackson-user] Using a converter only on root object/collection
Hi Tatu, thanks for the reply.
I wanted to avoid using a wrapper as my REST API is built on top of
interfaces used for other things, and I would like to keep them untouched.
I have a large number of calls returning any Collection (Set, List,
UnmodifiableSet, etc.), so doing it purely on Jackson side would avoid
modifying all of them. I found it to be elegant to properly separate
business logic from serialization logic.
I'm curious, why isn't BeanSerializerModifier.modifySerializer() called for
Collection?
Thanks,
On Tuesday, February 7, 2017 at 8:28:56 PM UTC+1, Tatu Saloranta wrote:
>
> There is no functionality to do it the way you suggested (although
> immutability of classes is not a blocker, you could use mix-in
> annotations).
>
> But wouldn't it be simpler to use a simple wrapper structure to get
> structure match the output, instead of trying to change the whole
> serialization logic to produce different structure than natural one?
>
> public class Wrapper {
> public List items;
>
>public Wrapper(List l) { items = l; }
>
> public int getSize() { return items.size(); }
> }
>
> That would produce output like what you are looking for.
>
> -+ Tatu +-
>
>
>
> On Tue, Feb 7, 2017 at 6:26 AM, Clément Poulain > wrote:
> > Hi there,
> >
> > I'm trying to implement pagination using Jersey and Jackson. I don't
> want to
> > modify my API, so I would like the pagination to take place during
> > serialization.
> > To simplify, lets pretend I simply want to add the size of a collection
> when
> > serializing it.
> >
> > The current output is:
> >
> > [
> > {
> > pojo1
> > }, {
> > pojo2
> > }, {
> > pojo3
> > }
> > ]
> >
> > What I try to get is:
> >
> > {
> > size: 3,
> > items: [
> > {
> > pojo1
> > }, {
> > pojo2
> > }, {
> > pojo3
> > }
> > ]
> > }
> >
> > I don't have control on the collections I receive to serialize, so I
> cannot
> > annotate a class like described in
> > http://www.cowtowncoder.com/blog/archives/2013/10/entry_482.html.
> >
> > I tried to register a `BeanSerializerModifier` to my `ObjectMapper` but
> I
> > have two issues:
> >
> > 1. it looks like collections (List, Set...) don't go through my modifier
> >
> > MAPPER.registerModule(new SimpleModule().setSerializerModifier(new
> > BeanSerializerModifier() {
> > @Override
> > public JsonSerializer modifySerializer(SerializationConfig
> config,
> > BeanDescription desc, JsonSerializer serializer) {
> >
> > System.out.println(desc.getBeanClass()); // <== prints "pojo",
> > "int", "String" ... but never "Collection" or "Set" or "List" or...
> >
> > return serializer;
> > }
> > }));
> >
> >
> > 2. (let's say we solve 1.) How to make sure this conversion occurs only
> for
> > root collection and not for nested collections inside pojo?
> > I'm asking because I tried also to use a `StdConverter` instead of a
> > `BeanSerializerModifier`:
> >
> > MAPPER.registerModule(new SimpleModule()
> > .addSerializer(Collection.class, new
> > StdDelegatingSerializer(Collection.class,
> > new StdConverter() {
> > @Override
> > public PaginationCollection convert(Collection value) {
> > return new PaginationCollection(value);
> > }
> > }))
> >
> > It logically ends up into a `StackOverflowException` as
> > `PaginationCollection` is also containing a `Collection` (for "items"),
> > which in turn was converted to `PaginationCollection`, etc, etc.
> > Even if the final solution does not involve a `Converter`, this will
> need to
> > be handled properly.
> >
> > TL;DR: what is the best way to modify serialization for root collection
> > only?
> >
> > Thanks!
> >
> > --
> > You received this message because you are subscribed to the Google
> Groups
> > "jackson-user" group.
> > To unsubscribe from this group and stop receiving emails from it, send
> an
> > email to jackson-user...@googlegroups.com .
> > To post to this group, send email to jackso...@googlegroups.com
> .
> > For more options, visit https://groups.google.com/d/optout.
>
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Re: [jackson-user] Using a converter only on root object/collection
There is no functionality to do it the way you suggested (although
immutability of classes is not a blocker, you could use mix-in
annotations).
But wouldn't it be simpler to use a simple wrapper structure to get
structure match the output, instead of trying to change the whole
serialization logic to produce different structure than natural one?
public class Wrapper {
public List items;
public Wrapper(List l) { items = l; }
public int getSize() { return items.size(); }
}
That would produce output like what you are looking for.
-+ Tatu +-
On Tue, Feb 7, 2017 at 6:26 AM, Clément Poulain wrote:
> Hi there,
>
> I'm trying to implement pagination using Jersey and Jackson. I don't want to
> modify my API, so I would like the pagination to take place during
> serialization.
> To simplify, lets pretend I simply want to add the size of a collection when
> serializing it.
>
> The current output is:
>
> [
> {
> pojo1
> }, {
> pojo2
> }, {
> pojo3
> }
> ]
>
> What I try to get is:
>
> {
> size: 3,
> items: [
> {
> pojo1
> }, {
> pojo2
> }, {
> pojo3
> }
> ]
> }
>
> I don't have control on the collections I receive to serialize, so I cannot
> annotate a class like described in
> http://www.cowtowncoder.com/blog/archives/2013/10/entry_482.html.
>
> I tried to register a `BeanSerializerModifier` to my `ObjectMapper` but I
> have two issues:
>
> 1. it looks like collections (List, Set...) don't go through my modifier
>
> MAPPER.registerModule(new SimpleModule().setSerializerModifier(new
> BeanSerializerModifier() {
> @Override
> public JsonSerializer modifySerializer(SerializationConfig config,
> BeanDescription desc, JsonSerializer serializer) {
>
> System.out.println(desc.getBeanClass()); // <== prints "pojo",
> "int", "String" ... but never "Collection" or "Set" or "List" or...
>
> return serializer;
> }
> }));
>
>
> 2. (let's say we solve 1.) How to make sure this conversion occurs only for
> root collection and not for nested collections inside pojo?
> I'm asking because I tried also to use a `StdConverter` instead of a
> `BeanSerializerModifier`:
>
> MAPPER.registerModule(new SimpleModule()
> .addSerializer(Collection.class, new
> StdDelegatingSerializer(Collection.class,
> new StdConverter() {
> @Override
> public PaginationCollection convert(Collection value) {
> return new PaginationCollection(value);
> }
> }))
>
> It logically ends up into a `StackOverflowException` as
> `PaginationCollection` is also containing a `Collection` (for "items"),
> which in turn was converted to `PaginationCollection`, etc, etc.
> Even if the final solution does not involve a `Converter`, this will need to
> be handled properly.
>
> TL;DR: what is the best way to modify serialization for root collection
> only?
>
> Thanks!
>
> --
> You received this message because you are subscribed to the Google Groups
> "jackson-user" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to jackson-user+unsubscr...@googlegroups.com.
> To post to this group, send email to jackson-user@googlegroups.com.
> For more options, visit https://groups.google.com/d/optout.
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[jackson-user] Using a converter only on root object/collection
Hi there,
I'm trying to implement pagination using Jersey and Jackson. I don't want
to modify my API, so I would like the pagination to take place during
serialization.
To simplify, lets pretend I simply want to add the size of a collection
when serializing it.
The current output is:
[
{
pojo1
}, {
pojo2
}, {
pojo3
}
]
What I try to get is:
{
size: 3,
items: [
{
pojo1
}, {
pojo2
}, {
pojo3
}
]
}
I don't have control on the collections I receive to serialize, so I cannot
annotate a class like described in
http://www.cowtowncoder.com/blog/archives/2013/10/entry_482.html.
I tried to register a `BeanSerializerModifier` to my `ObjectMapper` but I
have two issues:
*1.* it looks like collections (List, Set...) don't go through my modifier
MAPPER.registerModule(new SimpleModule().setSerializerModifier(new
BeanSerializerModifier() {
@Override
public JsonSerializer modifySerializer(SerializationConfig config,
BeanDescription desc, JsonSerializer serializer) {
System.out.println(desc.getBeanClass()); // <== prints "pojo",
"int", "String" ... but never "Collection" or "Set" or "List" or...
return serializer;
}
}));
*2. *(let's say we solve 1.) How to make sure this conversion occurs only
for *root* collection and *not* for nested collections inside pojo?
I'm asking because I tried also to use a `StdConverter` instead of a
`BeanSerializerModifier`:
MAPPER.registerModule(new SimpleModule()
.addSerializer(Collection.class, new
StdDelegatingSerializer(Collection.class,
new StdConverter() {
@Override
public PaginationCollection convert(Collection value) {
return new PaginationCollection(value);
}
}))
It logically ends up into a `StackOverflowException` as
`PaginationCollection` is also containing a `Collection` (for "items"),
which in turn was converted to `PaginationCollection`, etc, etc.
Even if the final solution does not involve a `Converter`, this will need
to be handled properly.
TL;DR: what is the best way to modify serialization for *root collection*
only?
Thanks!
--
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