com.fasterxml.jackson.databind

Enum DeserializationFeature

java.lang.Object

java.lang.Enum<DeserializationFeature>

com.fasterxml.jackson.databind.DeserializationFeature

All Implemented Interfaces:

ConfigFeature, Serializable, Comparable<DeserializationFeature>

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.

Enum Constant Summary

Enum Constants

Enum Constant and Description
ACCEPT_EMPTY_STRING_AS_NULL_OBJECT Feature that can be enabled to allow JSON empty String value ("") to be bound to POJOs as null.
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.
EAGER_DESERIALIZER_FETCH Feature that determines whether ObjectReader should try to eagerly fetch necessary JsonDeserializer when possible.
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').
FAIL_ON_NUMBERS_FOR_ENUMS Feature that determines whether JSON integer numbers are valid values to be used for deserializing Java enum values.
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 JsonMappingException) or not.
READ_ENUMS_USING_TO_STRING Feature that determines standard deserialization mechanism used for Enum values: if enabled, Enums are assumed to have been serialized using return value of Enum.toString(); if disabled, return value of Enum.name() is assumed to have been used.
READ_UNKNOWN_ENUM_VALUES_AS_NULL Feature that allows unknown Enum values to be parsed as null values.
UNWRAP_ROOT_VALUE Feature to allow "unwrapping" root-level JSON value, to match setting of SerializationFeature.WRAP_ROOT_VALUE used for serialization.
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.
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.
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).
WRAP_EXCEPTIONS Feature that determines whether Jackson code should catch and wrap Exceptions (but never Errors!) to add additional information about location (within input) of problem or not.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	enabledByDefault() Accessor for checking whether this feature is enabled by default.
int	getMask() Returns bit mask for this feature instance
static DeserializationFeature	valueOf(String name) Returns the enum constant of this type with the specified name.
static DeserializationFeature[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

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.

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" floating point numbers will by default be deserialized using whatever is the most compact integral type, to optimize efficiency.

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.

READ_ENUMS_USING_TO_STRING

public static final DeserializationFeature READ_ENUMS_USING_TO_STRING

Feature that determines standard deserialization mechanism used for Enum values: if enabled, Enums are assumed to have been serialized using return value of Enum.toString(); if disabled, return value of Enum.name() is assumed to have been used.

Note: this feature should usually have same value as SerializationFeature.WRITE_ENUMS_USING_TO_STRING.

Feature is disabled by default.

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 JsonMappingException) or not. This setting only takes effect after all other handling methods for unknown properties have been tried, and property remains unhandled.

Feature is enabled by default (meaning that a JsonMappingException will be thrown if an unknown property is encountered).

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 JsonProcessingException 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 disabled by default.

FAIL_ON_NUMBERS_FOR_ENUMS

public static final DeserializationFeature FAIL_ON_NUMBERS_FOR_ENUMS

Feature that determines whether JSON integer numbers are valid values to be used for deserializing Java enum values. If set to 'false' numbers are acceptable and are used to map to ordinal() of matching enumeration value; if 'true', numbers are not allowed and a JsonMappingException will be thrown. Latter behavior makes sense if there is concern that accidental mapping from integer values to enums might happen (and when enums are always serialized as JSON Strings)

Feature is disabled by default.

WRAP_EXCEPTIONS

public static final DeserializationFeature WRAP_EXCEPTIONS

Feature that determines whether Jackson code should catch and wrap 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 (exception specifically being that IOExceptions may be passed as is, since they are declared as throwable); 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.

Feature is enabled by default.

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_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 JsonMappingException 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 to POJOs as 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 enable, empty JSON String can be taken to be equivalent of JSON null.

Feature is enabled by default.

READ_UNKNOWN_ENUM_VALUES_AS_NULL

public static final DeserializationFeature READ_UNKNOWN_ENUM_VALUES_AS_NULL

Feature that allows unknown Enum values to be parsed as null values. If disabled, unknown Enum values will throw exceptions.

Note that in some cases this will basically ignore unknown Enum values; this is the keys for keys of EnumMap and values of EnumSet (because nulls are not accepted in these cases).

Feature is disabled by default.

Since:

2.0

EAGER_DESERIALIZER_FETCH

public static final DeserializationFeature EAGER_DESERIALIZER_FETCH

Feature that determines whether ObjectReader should try to eagerly fetch necessary JsonDeserializer 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.

Since:

2.1

Method Detail

values

public static DeserializationFeature[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (DeserializationFeature c : DeserializationFeature.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static DeserializationFeature valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (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 type 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