CODEWITHSUNDEEP
javajackson
Adamovskiy
Adamovskiy

Reputation: 1583

Dynamic Jackson fields filtering

I'm trying to implement wrapper class, that will be serialized by Jackson with omitting fields depending on runtime configuration:

class Partial<T> {
    T value;
    List<String> fieldsToSkip;
}

This

class Example{int a=1; int b=2; int c=3;}
new Partial(new Example(), asList("b"));

suppose to be serialized to {"a":1, "c":3}.

@JsonUnwrapped with @JsonFilter seems to be right approach here. The problem is that the filter works on value field level, where there's no access to host Partial instance.

What is the best way to implement such thing?

Upvotes: 1

Views: 793

Answers (1)

Manos Nikolaidis
Manos Nikolaidis

Reputation: 22224

You can create at run time an ObjectWriter with a filter also defined at run time and use it to write the value in Partial:

 SimpleBeanPropertyFilter filter = 
     SimpleBeanPropertyFilter.serializeAllExcept(new HashSet<>(partial.fieldsToSkip));
 FilterProvider fp = new SimpleFilterProvider().addFilter("exampleFilter", filter);
 String text = objectMapper.writer(fp).writeValueAsString(partial.value);

and tell Jackson that this filter should be applied to Example class:

 @JsonFilter("exampleFilter")
 class Example{int a=1; int b=2; int c=3;}

You may want to change fieldsToSkip to a Set<String>

Upvotes: 1

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