Jackson-databind: @JsonProperty(access = Access.READ_ONLY) - unexpected behaviour

[weaselmetal]

Hey,

I was hoping to make use of @JsonProperty(access = Access.READ_ONLY), but failed.

Assume this class:

public class TestPojo
{
    private String firstName;

    private String lastName;

    @JsonProperty(access = Access.READ_ONLY)
    public String getFullName()
    {
        return firstName + " " + lastName;
    }

    public String getFirstName()
    {
        return firstName;
    }

    public void setFirstName(String firstName)
    {
        this.firstName = firstName;
    }

    public String getLastName()
    {
        return lastName;
    }

    public void setLastName(String lastName)
    {
        this.lastName = lastName;
    }
}

I couldn't find a way to stop the deserializer from attempting to deserialize the field "fullName".
The only thing that helps is to create a setter and annotate it with @JsonIgnore. However, that setter does not make sense and I don't want to have it. Is this a bug in behaviour or am I missing something? Thanks

[cowtowncoder]

That does sound like a bug indeed. Which version are you using?

[cowtowncoder]

Whoa. There is no unit test coverage for value of READ_ONLY. That should not be the case... No wonder there could be a bug lurking in there.

[cowtowncoder]

I can reproduce this with 2.6. Looks like READ_ONLY does actually hide/remove setter method (my test fails with "unknown property"), but will not mark it as ignorable, which it probably should do.

[cowtowncoder]

I added a failing test case for this, but not sure how easy it will be to pipe "do ignore" information.

Thank you for reporting the problem again.

[weaselmetal]

Thanks for dealing with the issue and sorry for the lack of details in my description. Afaik Access.READ_ONLY has just been added in 2.6. I also got the UnrecognizedPropertyException: Unrecognized field "fullName" ... not marked as ignorable

[cowtowncoder]

Correct, it's 2.6 only which is why I realized that asking for version wasn't fully necessary (but only after asking).

The fix would be to essentially carry along the name as "ignorable" property, similar to how @JsonIgnore is tracked. But I'll need to see how that plumbing is handled, since discovery occurs in bit different place.

[mewert]

Hi,

is there some easy workaround, until this is fixed? I mean instead of implementing a noop setter method?

The annotation @JsonIgnoreProperties sounds like it could help here. But it also has no effect, if I add it to a getter, regardless which values I choose for allowGetters or allowSetters.

Update: It seems that I found a solution by adding

@JsonIgnoreProperties(value="some_field", allowGetters = true, allowSetters = false)

to the class. So this could be a solution, if we don't need the @JsonIgnoreProperties annotation on class level for other purposes.

[cowtowncoder]

@plattfish thank you for sharing this. I am hoping to address this, along with some issues with creator property handling, in 2.8.

[thedoctor]

Any movement here? I just bumped into this issue.

[heruan]

Don't know if related, but I'm experiencing this with a Map:

public class Ticket {

    @JsonProperty(access = Access.READ_ONLY)
    @JsonSerialize(using = MapToArraySerializer.class)
    public SortedMap<Timer, Integer> getServiceTimers() {
        // ...
    }

}

All works on serialization, but on deserialization of Ticket I get this exception:

Can not find a (Map) Key deserializer for type [simple type, class Timer]
 at [Source: java.io.SequenceInputStream@1100946d; line: 1, column: 1]
    at com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:261)

I'm on Jackson 2.8.

[jyothri]

+1
I also have come across this issue. I am using spring boot which pulled in Jackson version 2.6.5

[msfanous]

This disabling this feature on your ObjectMapper helped me avoid this issue.
ObjectMapper mapper = new ObjectMapper(); mapper.disable(MapperFeature.USE_GETTERS_AS_SETTERS);

[philbayer]

Hi @cowtowncoder - any word on a fix for this? I am using 2.8.5, and it appears the issue persists. @plattfish's solution did not work for me.
I don't mind trying to isolate the issue myself if it will speed up development of a patch.

[cowtowncoder]

@philbayer no activity on this one. I have been slowly fixing similar bugs, hope to have another look at this one. Thank you for the ping, for some reason I hadn't tagged it.

[cowtowncoder]

@heruan in a way it is related, if and when expectation is that Map is not to be deserialized, although @msfanous suggestion is also relevant.

[jyothri]

@cowtowncoder I pulled in v2.8.7 for jackson-databind but unable to do deserialize on a

    @JsonProperty(access=Access.WRITE_ONLY)
    private String passwordPlaintext;

Only if I remove the access modifier, I am able to deserialize the json properly. However I do not want to involve this in serialization. Is this fixed in this same issue?

[cowtowncoder]

@jyothri If there are remaining problems, please file a new issue, with reproduction. It is possible that fix is incomplete, or something in your setup differs significantly; I don't know without reproduction.

[YashArya]

Has this been fixed in 2.8.9? I still seem to be seeing this issue.

Edit: Plattfish's workaround works for me!

[cowtowncoder]

@YashArya Please read my previous comment. It is fixed to the best of my knowledge -- for remaining problems, if any, please file a new issue with reproduction showing what is not working.

[AngorSTV]

I agree, this does not work until now
@JsonProperty(access = JsonProperty.Access.READ_ONLY)
public boolean isEnriched() {
return enrichedPayload != null;
}
and I have, when I deserialise
Unrecognized field "enriched" (class Transaction), not marked as ignorable

I use spring-boot 1.5.10

[cowtowncoder]

@AngorSTV Please do not keep adding comments on closed issues -- I really do not care for +1s if no one files a new case with reproduction. Reproduction must not rely on frameworks like Spring Boot.

[iuliana]

Neither @JsonProperty(access = JsonProperty.Access.WRITE_ONLY) on field or@JsonIgnoreProperties(value="password", allowSetters = true) work for me in 2.9.9.

I just cannot set the value during deserialization.
Maybe you should consider reopening this.

[jwgmeligmeyling]

Try READ only, I think the annotations are from the frameworks perspective, not the client.

[cowtowncoder]

@JWGmeligMeyling is correct: naming is not be as intuitive as I originally hoped: [INCORRECT EXPLANATION, REMOVED]

[iuliana]

Thank you, but damn the documentation on this is confusing.

        /**
         * Access setting that means that the property may only be written (set)
         * for deserialization,
         * but will not be read (get) on serialization, that is, the value of the property
         * is not included in serialization.
         */
        WRITE_ONLY,

It says that property may only be written (set) for deserialization which is what I needed. :)

[iuliana]

READ_ONLY doesn't do it either. This is my setup with Spring Boot: Sample
In the proof directory there are screenshots with execution paused while PersonManagerApplicationTests.testPOST().

[cowtowncoder]

@iuliana Can you please file a new issue with the link. I don't usually re-open issues in cases where there has been a previous fix as that will make release notes more difficult to follow up.
I will try to improve javadocs wrt setting as well.

[cowtowncoder]

Also: my earlier explanation was exactly backwards. Javadocs state it correctly (if not well): READ_ONLY refers to POJO being handled in read-only way, and WRITE_ONLY opposite.
So Java-centric, not JSON-centric.

I really should have named values differently (GETTER_ONLY, SETTER_ONLY, perhaps).

[T3rm1]

@cowtowncoder

I think this is still not fixed. I have the same problem with 2.10.3
My getter is annotated with @JsonProperty(value = "t", access = JsonProperty.Access.READ_ONLY)
The BeanDeserializerBase tries to deserialize it which results into Caused by: com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "t"

Here is the stacktrace:

Caused by: com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "t" 
    at com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException.from(UnrecognizedPropertyException.java:61)
    at com.fasterxml.jackson.databind.DeserializationContext.handleUnknownProperty(DeserializationContext.java:843)
    at com.fasterxml.jackson.databind.deser.std.StdDeserializer.handleUnknownProperty(StdDeserializer.java:1206)
    at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownProperty(BeanDeserializerBase.java:1592)
    at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownVanilla(BeanDeserializerBase.java:1570)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:294)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeOther(BeanDeserializer.java:189)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:161)
    at com.fasterxml.jackson.databind.jsontype.impl.AsPropertyTypeDeserializer._deserializeTypedForId(AsPropertyTypeDeserializer.java:130)
    at com.fasterxml.jackson.databind.jsontype.impl.AsPropertyTypeDeserializer.deserializeTypedFromObject(AsPropertyTypeDeserializer.java:97)
    at com.fasterxml.jackson.databind.jsontype.impl.AsPropertyTypeDeserializer.deserializeTypedFromAny(AsPropertyTypeDeserializer.java:193)
    at com.fasterxml.jackson.databind.deser.std.UntypedObjectDeserializer$Vanilla.deserializeWithType(UntypedObjectDeserializer.java:712)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:288)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:245)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:27)
    at com.fasterxml.jackson.databind.jsontype.impl.AsArrayTypeDeserializer._deserialize(AsArrayTypeDeserializer.java:120)
    at com.fasterxml.jackson.databind.jsontype.impl.AsArrayTypeDeserializer.deserializeTypedFromArray(AsArrayTypeDeserializer.java:53)
    at com.fasterxml.jackson.databind.jsontype.impl.AsPropertyTypeDeserializer.deserializeTypedFromAny(AsPropertyTypeDeserializer.java:191)
    at com.fasterxml.jackson.databind.deser.std.UntypedObjectDeserializer$Vanilla.deserializeWithType(UntypedObjectDeserializer.java:712)
    at com.fasterxml.jackson.databind.deser.impl.TypeWrappedDeserializer.deserialize(TypeWrappedDeserializer.java:68)
    at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4218)
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3275)
    at org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer.deserialize(GenericJackson2JsonRedisSerializer.java:150)
    ... 138 more

FYI:_removeUnwantedAccessor is not called at all.