JsonParser cannot getText() for input stream on MismatchedInputException

I’ve stumbled upon a situation in which I’m not able to get the textual representation of the current token.

I have the following class:

public class Test {
    public Boolean value;
    public Boolean getValue() { return value; }
    public void setValue(Boolean value) { this.value = value; }
}

And the following object mapper:

ObjectMapper objectMapper = new ObjectMapper();
objectMapper.disable(MapperFeature.ALLOW_COERCION_OF_SCALARS);

I’m trying to deserialize something that would result in a MismatchedInputException. I’m providing an integer to something that should be a boolean:

try {
    objectMapper.readValue("{ \"value\": 1 }", Test.class);
} catch (MismatchedInputException exception) {
    JsonParser parser = (JsonParser) exception.getProcessor();
    System.out.println(parser.currentToken());
    System.out.println(parser.getText());
} catch (Exception exception) {}

This results in:

VALUE_NUMBER_INT
1

as expected.

What’s the use case for this you might ask? Whenever the clients of my service send me something incorrect I want to be able to give them detailed information about what went wrong. For example, “I was expecting a boolean but you gave me 1, which is an integer.”.

Now, if I use an input stream instead of a string, I can no longer access the text and get a null instead:

objectMapper.readValue(new ByteArrayInputStream("{ \"value\": 1 }".getBytes()), Test.class);

VALUE_NUMBER_INT

On Jackson 2.10.2.

[cowtowncoder]

So, the actual fix is for:

https://github.com/FasterXML/jackson-core/issues/606

and takes care of this problem. Will go in 2.11.0.

[cowtowncoder]

@joca-bt Please file another one, easier to track – you can refer to this issue as background (to avoid some explanation).

And yes, it is quite possible there are other cases where this won’t work as it is unfortunately not something that can be solved in general fashion (to retain content, it must be accessed before input is auto-closed).