com.fasterxml.jackson.databind.deser

Class DeserializationProblemHandler

  • java.lang.Object
    • com.fasterxml.jackson.databind.deser.DeserializationProblemHandler

  • public abstract class DeserializationProblemHandler
extends Object
    This is the class that can be registered (via DeserializationConfig object owner by ObjectMapper) to get called when a potentially recoverable problem is encountered during deserialization process. Handlers can try to resolve the problem, throw an exception or just skip the content.

    Default implementations for all methods implemented minimal "do nothing" functionality, which is roughly equivalent to not having a registered listener at all. This allows for only implemented handler methods one is interested in, without handling other cases.

    NOTE: it is typically NOT acceptable to simply do nothing, because this will result in unprocessed tokens being left in token stream (read via JsonParser, in case a structured (JSON Object or JSON Array) value is being pointed to by parser.

    • Constructor Detail

      • DeserializationProblemHandler

        public DeserializationProblemHandler()

    • Method Detail

      • handleUnknownProperty

        public boolean handleUnknownProperty(DeserializationContext ctxt,
                            JsonParser jp,
                            JsonDeserializer<?> deserializer,
                            Object beanOrClass,
                            String propertyName)
                              throws IOException,
                                     JsonProcessingException
        Method called when a JSON Map ("Object") entry with an unrecognized name is encountered. Content (supposedly) matching the property are accessible via parser that can be obtained from passed deserialization context. Handler can also choose to skip the content; if so, it MUST return true to indicate it did handle property successfully. Skipping is usually done like so: 
          jp.skipChildren();

        Note: version 1.2 added new deserialization feature (DeserializationConfig.DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES). It will only have effect after handler is called, and only if handler did not handle the problem.

        Parameters:
        beanOrClass - Either bean instance being deserialized (if one has been instantiated so far); or Class that indicates type that will be instantiated (if no instantiation done yet: for example when bean uses non-default constructors)
        jp - Parser to use for handling problematic content
        Returns:
        True if the problem is resolved (and content available used or skipped); false if the handler did not anything and the problem is unresolved. Note that in latter case caller will either throw an exception or explicitly skip the content, depending on configuration.
        Throws:
        IOException
        JsonProcessingException

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