Module tools.jackson.databind
Package tools.jackson.databind

Enum Class DeserializationFeature

java.lang.Object
java.lang.Enum<DeserializationFeature>
tools.jackson.databind.DeserializationFeature
All Implemented Interfaces:
Serializable, Comparable<DeserializationFeature>, Constable, ConfigFeature
public enum DeserializationFeature extends Enum<DeserializationFeature> implements ConfigFeature
Enumeration that defines simple on/off features that affect the way Java objects are deserialized from JSON

Note that features can be set both through ObjectMapper (as sort of defaults) and through ObjectReader. In first case these defaults must follow "config-then-use" patterns (i.e. defined once, not changed afterwards); all per-call changes must be done using ObjectReader.

Note that features that do not indicate version of inclusion were available in Jackson 3.0 (or earlier); only later additions indicate version of inclusion.

  • Enum Constant Details

    • USE_BIG_DECIMAL_FOR_FLOATS

      public static final DeserializationFeature USE_BIG_DECIMAL_FOR_FLOATS
      Feature that determines whether JSON floating point numbers are to be deserialized into BigDecimals if only generic type description (either Object or Number, or within untyped Map or Collection context) is available. If enabled such values will be deserialized as BigDecimals; if disabled, will be deserialized as Doubles.

      NOTE: one related aspect of BigDecimal handling that may need configuring is whether trailing zeroes are trimmed: JsonNodeFeature.STRIP_TRAILING_BIGDECIMAL_ZEROES is used for optionally enabling this for JsonNode values.

      Feature is disabled by default, meaning that "untyped" floating point numbers will by default be deserialized as Doubles (choice is for performance reason -- BigDecimals are slower than Doubles).

    • USE_BIG_INTEGER_FOR_INTS

      public static final DeserializationFeature USE_BIG_INTEGER_FOR_INTS
      Feature that determines whether JSON integral (non-floating-point) numbers are to be deserialized into BigIntegers if only generic type description (either Object or Number, or within untyped Map or Collection context) is available. If enabled such values will be deserialized as BigIntegers; if disabled, will be deserialized as "smallest" available type, which is either Integer, Long or BigInteger, depending on number of digits.

      Feature is disabled by default, meaning that "untyped" integral numbers will by default be deserialized using whatever is the most compact integral type, to optimize efficiency.

    • USE_LONG_FOR_INTS

      public static final DeserializationFeature USE_LONG_FOR_INTS
      Feature that determines how "small" JSON integral (non-floating-point) numbers -- ones that fit in 32-bit signed integer (`int`) -- are bound when target type is loosely typed as Object or Number (or within untyped Map or Collection context). If enabled, such values will be deserialized as Long; if disabled, they will be deserialized as "smallest" available type, Integer.

      Note: if USE_BIG_INTEGER_FOR_INTS is enabled, it has precedence over this setting, forcing use of BigInteger for all integral values.

      Feature is disabled by default, meaning that "untyped" integral numbers will by default be deserialized using Integer if value fits.

    • USE_JAVA_ARRAY_FOR_JSON_ARRAY

      public static final DeserializationFeature USE_JAVA_ARRAY_FOR_JSON_ARRAY
      Feature that determines whether JSON Array is mapped to Object[] or List<Object> when binding "untyped" objects (ones with nominal type of java.lang.Object). If true, binds as Object[]; if false, as List<Object>.

      Feature is disabled by default, meaning that JSON arrays are bound as Lists.

    • FAIL_ON_UNKNOWN_PROPERTIES

      public static final DeserializationFeature FAIL_ON_UNKNOWN_PROPERTIES
      Feature that determines whether encountering of unknown properties (ones that do not map to a property, and there is no "any setter" or handler that can handle it) should result in a failure (by throwing a DatabindException) or not. This setting only takes effect after all other handling methods for unknown properties have been tried, and property remains unhandled. Enabling this feature means that a DatabindException will be thrown if an unknown property is encountered.

      Feature is disabled by default as of Jackson 3.0 (in 2.x it was enabled).

    • FAIL_ON_NULL_FOR_PRIMITIVES

      public static final DeserializationFeature FAIL_ON_NULL_FOR_PRIMITIVES
      Feature that determines whether encountering of JSON null is an error when deserializing into Java primitive types (like 'int' or 'double'). If it is, a DatabindException is thrown to indicate this; if not, default value is used (0 for 'int', 0.0 for double, same defaulting as what JVM uses).

      Feature is enabled by default as of Jackson 3.0 (in 2.x it was disabled).

    • FAIL_ON_INVALID_SUBTYPE

      public static final DeserializationFeature FAIL_ON_INVALID_SUBTYPE
      Feature that determines what happens when type of a polymorphic value (indicated for example by JsonTypeInfo) cannot be found (missing) or resolved (invalid class name, non-mappable id); if enabled, an exception is thrown; if false, null value is used instead.

      Feature is enabled by default so that exception is thrown for missing or invalid type information.

    • FAIL_ON_READING_DUP_TREE_KEY

      public static final DeserializationFeature FAIL_ON_READING_DUP_TREE_KEY
      Feature that determines what happens when reading JSON content into tree (TreeNode) and a duplicate key is encountered (property name that was already seen for the JSON Object). If enabled, DatabindException will be thrown; if disabled, no exception is thrown and the new (later) value overwrites the earlier value.

      Note that this property does NOT affect other aspects of data-binding; that is, no detection is done with respect to POJO properties or Map keys. New features may be added to control additional cases.

      Feature is disabled by default so that no exception is thrown.

    • FAIL_ON_IGNORED_PROPERTIES

      public static final DeserializationFeature FAIL_ON_IGNORED_PROPERTIES
      Feature that determines what happens when a property that has been explicitly marked as ignorable is encountered in input: if feature is enabled, DatabindException is thrown; if false, property is quietly skipped.

      Feature is disabled by default so that no exception is thrown.

    • FAIL_ON_UNRESOLVED_OBJECT_IDS

      public static final DeserializationFeature FAIL_ON_UNRESOLVED_OBJECT_IDS
      Feature that determines what happens if an Object Id reference is encountered that does not refer to an actual Object with that id ("unresolved Object Id"): either an exception UnresolvedForwardReference containing information about UnresolvedId is thrown (true), or a null object is used instead (false). Note that if this is set to false, no further processing is done; specifically, if reference is defined via setter method, that method will NOT be called.

      Feature is enabled by default, so that unknown Object Ids will result in an exception being thrown, at the end of deserialization.

    • FAIL_ON_MISSING_CREATOR_PROPERTIES

      public static final DeserializationFeature FAIL_ON_MISSING_CREATOR_PROPERTIES
      Feature that determines what happens if one or more Creator properties (properties bound to parameters of Creator method (constructor or static factory method)) are missing value to bind to from content. If enabled, such missing values result in a DatabindException being thrown with information on the first one (by index) of missing properties. If disabled, and if property is NOT marked as required, missing Creator properties are filled with null values provided by deserializer for the type of parameter (usually null for Object types, and default value for primitives; but redefinable via custom deserializers).

      Note that having an injectable value counts as "not missing".

      Feature is disabled by default, so that no exception is thrown for missing creator property values, unless they are explicitly marked as `required`.

    • FAIL_ON_NULL_CREATOR_PROPERTIES

      public static final DeserializationFeature FAIL_ON_NULL_CREATOR_PROPERTIES
      Feature that determines what happens if one or more Creator properties (properties bound to parameters of Creator method (constructor or static factory method)) are bound to null values - either from the JSON or as a default value. This is useful if you want to avoid nulls in your codebase, and particularly useful if you are using Java or Scala Optionals for non-mandatory fields. Feature is disabled by default, so that no exception is thrown for missing creator property values, unless they are explicitly marked as `required`.

    • FAIL_ON_MISSING_EXTERNAL_TYPE_ID_PROPERTY

      public static final DeserializationFeature FAIL_ON_MISSING_EXTERNAL_TYPE_ID_PROPERTY
      Feature that determines what happens when a property annotated with JsonTypeInfo.As.EXTERNAL_PROPERTY is missing, but associated type id is available. If enabled, a DatabindException is always thrown when property value is missing (if type id does exist); if disabled, exception is only thrown if property is marked as required.

      Feature is enabled by default, so that exception is thrown when a subtype property is missing.

    • FAIL_ON_TRAILING_TOKENS

      public static final DeserializationFeature FAIL_ON_TRAILING_TOKENS
      Feature that determines behavior for data-binding after binding the root value. If feature is enabled, one more call to JsonParser.nextToken() is made to ensure that no more tokens are found (and if any is found, MismatchedInputException is thrown); if disabled, no further checks are made.

      Feature could alternatively be called READ_FULL_STREAM, since it effectively verifies that input stream contains only as much data as is needed for binding the full value, and nothing more (except for possible ignorable white space or comments, if supported by data format).

      <<<<<<< HEAD:src/main/java/tools/jackson/databind/DeserializationFeature.java NOTE: this feature should usually be disabled when reading from DataInput, since it cannot detect end-of-input efficiently (but by throwing an IOException). Disabling is NOT done automatically by Jackson: users are recommended to disable it.

      Feature is enabled by default as of Jackson 3.0 (in 2.x it was disabled). ======= Feature is disabled by default (so that no check is made for possible trailing token(s)) for backwards-compatibility reasons.

      Since:
      2.9 >>>>>>> 2.x:src/main/java/com/fasterxml/jackson/databind/DeserializationFeature.java

    • FAIL_ON_SUBTYPE_CLASS_NOT_REGISTERED

      public static final DeserializationFeature FAIL_ON_SUBTYPE_CLASS_NOT_REGISTERED
      Feature that determines behavior when deserializing polymorphic types that use Class-based Type Id mechanism (either JsonTypeInfo.Id.CLASS or JsonTypeInfo.Id.MINIMAL_CLASS): If enabled, an exception will be thrown if a subtype (Class) is encountered that has not been explicitly registered (by calling MapperBuilder.registerSubtypes(java.lang.Class<?>...) or using annotation JsonSubTypes).

      Note that for Type Name - based Type Id mechanism (JsonTypeInfo.Id.NAME) you already need to register the subtypes but with so this feature has no effect.

      Feature is disabled by default.

    • WRAP_EXCEPTIONS

      public static final DeserializationFeature WRAP_EXCEPTIONS
      Feature that determines whether Jackson code should catch and wrap non-Jackson Exceptions (but never Errors!) to add additional information about location (within input) of problem or not. If enabled, most exceptions will be caught and re-thrown; this can be convenient both in that all exceptions will be checked and declared, and so there is more contextual information. However, sometimes calling application may just want "raw" unchecked exceptions passed as is.

      NOTE: most of the time exceptions that may or may not be wrapped are of type RuntimeException: as mentioned earlier, JacksonExceptions) will always be passed as-is.

      Disabling this feature will mean that you will need to adjust your try/catch blocks to properly handle RuntimeExceptions. Failing to do so, may cause your application to crash due to unhandled exceptions.

      Feature is enabled by default.

    • FAIL_ON_UNEXPECTED_VIEW_PROPERTIES

      public static final DeserializationFeature FAIL_ON_UNEXPECTED_VIEW_PROPERTIES
      Feature that determines the handling of properties not included in the active JSON view during deserialization.

      When enabled, if a property is encountered during deserialization that is not part of the active view (as defined by JsonView), an exception is thrown. If disabled, the property is simply ignored.

      This feature is particularly useful in scenarios where strict adherence to the specified view is required and any deviation, such as the presence of properties not belonging to the view, should be reported as an error. It can enhance the robustness of data binding by ensuring that only the properties relevant to the active view are considered during deserialization, thereby preventing unintended data from being processed.

      Feature is disabled by default to maintain backward compatibility.

    • FAIL_ON_UNKNOWN_INJECT_VALUE

      public static final DeserializationFeature FAIL_ON_UNKNOWN_INJECT_VALUE
      Feature that determines the handling of injected properties during deserialization.

      When enabled, if an injected property without matching value is encountered during deserialization, an exception is thrown. When disabled, no exception is thrown. See JacksonInject.optional() for per-property override of this setting.

      This feature is enabled by default to maintain backwards-compatibility.

      See Also:

    • ACCEPT_SINGLE_VALUE_AS_ARRAY

      public static final DeserializationFeature ACCEPT_SINGLE_VALUE_AS_ARRAY
      Feature that determines whether it is acceptable to coerce non-array (in JSON) values to work with Java collection (arrays, java.util.Collection) types. If enabled, collection deserializers will try to handle non-array values as if they had "implicit" surrounding JSON array. This feature is meant to be used for compatibility/interoperability reasons, to work with packages (such as XML-to-JSON converters) that leave out JSON array in cases where there is just a single element in array.

      Feature is disabled by default.

    • UNWRAP_SINGLE_VALUE_ARRAYS

      public static final DeserializationFeature UNWRAP_SINGLE_VALUE_ARRAYS
      Feature that determines whether it is acceptable to coerce single value array (in JSON) values to the corresponding value type. This is basically the opposite of the ACCEPT_SINGLE_VALUE_AS_ARRAY feature. If more than one value is found in the array, a DatabindException is thrown.

      NOTE: only single wrapper Array is allowed: if multiple attempted, exception will be thrown.

      Feature is disabled by default.

    • UNWRAP_ROOT_VALUE

      public static final DeserializationFeature UNWRAP_ROOT_VALUE
      Feature to allow "unwrapping" root-level JSON value, to match setting of SerializationFeature.WRAP_ROOT_VALUE used for serialization. Will verify that the root JSON value is a JSON Object, and that it has a single property with expected root name. If not, a DatabindException is thrown; otherwise value of the wrapped property will be deserialized as if it was the root value.

      Feature is disabled by default.

    • ACCEPT_EMPTY_STRING_AS_NULL_OBJECT

      public static final DeserializationFeature ACCEPT_EMPTY_STRING_AS_NULL_OBJECT
      Feature that can be enabled to allow JSON empty String value ("") to be bound as null for POJOs and other structured values (Maps, Collections). If disabled, standard POJOs can only be bound from JSON null or JSON Object (standard meaning that no custom deserializers or constructors are defined; both of which can add support for other kinds of JSON values); if enabled, empty JSON String can be taken to be equivalent of JSON null.

      NOTE: this does NOT apply to scalar values such as Strings, booleans, numbers and date/time types; whether these can be coerced depends on MapperFeature.ALLOW_COERCION_OF_SCALARS.

      Feature is disabled by default.

    • ACCEPT_EMPTY_ARRAY_AS_NULL_OBJECT

      public static final DeserializationFeature ACCEPT_EMPTY_ARRAY_AS_NULL_OBJECT
      Feature that can be enabled to allow empty JSON Array value (that is, [ ] to be bound to POJOs null. If disabled, standard POJOs can only be bound from JSON null or JSON Object (standard meaning that no custom deserializers or constructors are defined; both of which can add support for other kinds of JSON values); if enabled, empty JSON Array will be taken to be equivalent of JSON null.

      Feature is disabled by default.

    • ACCEPT_FLOAT_AS_INT

      public static final DeserializationFeature ACCEPT_FLOAT_AS_INT
      Feature that determines whether coercion from JSON floating point number (anything with command (`.`) or exponent portion (`e` / `E')) to an expected integral number (`int`, `long`, `java.lang.Integer`, `java.lang.Long`, `java.math.BigDecimal`) is allowed or not. If enabled, coercion truncates value; if disabled, a DatabindException will be thrown.

      Feature is enabled by default.

    • EAGER_DESERIALIZER_FETCH

      public static final DeserializationFeature EAGER_DESERIALIZER_FETCH
      Feature that determines whether ObjectReader should try to eagerly fetch necessary ValueDeserializer when possible. This improves performance in cases where similarly configured ObjectReader instance is used multiple times; and should not significantly affect single-use cases.

      Note that there should not be any need to normally disable this feature: only consider that if there are actual perceived problems.

      Feature is enabled by default.

  • Method Details

    • values

      public static DeserializationFeature[] values()
      Returns an array containing the constants of this enum class, in the order they are declared.
      Returns:
      an array containing the constants of this enum class, in the order they are declared

    • valueOf

      public static DeserializationFeature valueOf(String name)
      Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (Extraneous whitespace characters are not permitted.)
      Parameters:
      name - the name of the enum constant to be returned.
      Returns:
      the enum constant with the specified name
      Throws:
      IllegalArgumentException - if this enum class has no constant with the specified name
      NullPointerException - if the argument is null

    • enabledByDefault

      public boolean enabledByDefault()
      Description copied from interface: ConfigFeature
      Accessor for checking whether this feature is enabled by default.
      Specified by:
      enabledByDefault in interface ConfigFeature

    • getMask

      public int getMask()
      Description copied from interface: ConfigFeature
      Returns bit mask for this feature instance
      Specified by:
      getMask in interface ConfigFeature

    • enabledIn

      public boolean enabledIn(int flags)
      Description copied from interface: ConfigFeature
      Convenience method for checking whether feature is enabled in given bitmask
      Specified by:
      enabledIn in interface ConfigFeature