StdDelegatingDeserializer (jackson-databind 2.14.0)

java.lang.Object
- com.fasterxml.jackson.databind.JsonDeserializer<T>
- - com.fasterxml.jackson.databind.deser.std.StdDeserializer<T>
  - - com.fasterxml.jackson.databind.deser.std.StdDelegatingDeserializer<T>

Type Parameters:

T - Target type to convert to, from delegate type

All Implemented Interfaces:

ContextualDeserializer, NullValueProvider, ResolvableDeserializer, ValueInstantiator.Gettable, Serializable
```
public class StdDelegatingDeserializer<T>
extends StdDeserializer<T>
implements ContextualDeserializer, ResolvableDeserializer
```
Deserializer implementation where given Java type is first deserialized by a standard Jackson deserializer into a delegate type; and then this delegate type is converted using a configured Converter into desired target type. Common delegate types to use are Map and JsonNode.
Note that although types (delegate, target) may be related, they must not be same; trying to do this will result in an exception.
Since 2.5 There is StdNodeBasedDeserializer that is a simplified version for cases where intermediate type is JsonNode

Since:

2.1

See Also:

StdNodeBasedDeserializer, Converter, Serialized Form

Nested Class Summary
- Nested classes/interfaces inherited from class com.fasterxml.jackson.databind.JsonDeserializer
  JsonDeserializer.None

Field Summary

Fields
Modifier and Type	Field and Description
`protected Converter<Object,T>`	`_converter` Converter that was used for creating `_delegateDeserializer`.
`protected JsonDeserializer<Object>`	`_delegateDeserializer` Underlying serializer for type `T`.
`protected JavaType`	`_delegateType` Fully resolved delegate type, with generic information if any available.

Fields inherited from class com.fasterxml.jackson.databind.deser.std.StdDeserializer
_valueClass, _valueType, F_MASK_ACCEPT_ARRAYS, F_MASK_INT_COERCIONS

Constructor Summary

Constructors
Modifier	Constructor and Description
	`StdDelegatingDeserializer(Converter<?,T> converter)`
	`StdDelegatingDeserializer(Converter<Object,T> converter, JavaType delegateType, JsonDeserializer<?> delegateDeserializer)`
`protected`	`StdDelegatingDeserializer(StdDelegatingDeserializer<T> src)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`protected Object`	`_handleIncompatibleUpdateValue(com.fasterxml.jackson.core.JsonParser p, DeserializationContext ctxt, Object intoValue)` Overridable handler method called when `deserialize(JsonParser, DeserializationContext, Object)` has been called with a value that is not compatible with delegate value.
`protected T`	`convertValue(Object delegateValue)` Method called to convert from "delegate value" (which was deserialized from JSON using standard Jackson deserializer for delegate type) into desired target type.
`JsonDeserializer<?>`	`createContextual(DeserializationContext ctxt, BeanProperty property)` Method called to see if a different (or differently configured) deserializer is needed to deserialize values of specified property.
`T`	`deserialize(com.fasterxml.jackson.core.JsonParser p, DeserializationContext ctxt)` Method that can be called to ask implementation to deserialize JSON content into the value type this serializer handles.
`T`	`deserialize(com.fasterxml.jackson.core.JsonParser p, DeserializationContext ctxt, Object intoValue)` Alternate deserialization method (compared to the most commonly used, `JsonDeserializer.deserialize(JsonParser, DeserializationContext)`), which takes in initialized value instance, to be configured and/or populated by deserializer.
`Object`	`deserializeWithType(com.fasterxml.jackson.core.JsonParser p, DeserializationContext ctxt, TypeDeserializer typeDeserializer)` Base implementation that does not assume specific type inclusion mechanism.
`JsonDeserializer<?>`	`getDelegatee()` Accessor that can be used to determine if this deserializer uses another deserializer for actual deserialization, by delegating calls.
`Class<?>`	`handledType()` Method for accessing concrete physical type of values this deserializer produces.
`LogicalType`	`logicalType()` Method for accessing logical type of values this deserializer produces.
`void`	`resolve(DeserializationContext ctxt)` Method called after deserializer instance has been constructed (and registered as necessary by provider objects), but before it has returned it to the caller.
`Boolean`	`supportsUpdate(DeserializationConfig config)` Introspection method that may be called to see whether deserializer supports update of an existing value (aka "merging") or not.
`protected StdDelegatingDeserializer<T>`	`withDelegate(Converter<Object,T> converter, JavaType delegateType, JsonDeserializer<?> delegateDeserializer)` Method used for creating resolved contextual instances.

Methods inherited from class com.fasterxml.jackson.databind.deser.std.StdDeserializer
_byteOverflow, _checkBooleanToStringCoercion, _checkCoercionFail, _checkDoubleSpecialValue, _checkFloatSpecialValue, _checkFloatToIntCoercion, _checkFloatToStringCoercion, _checkFromStringCoercion, _checkFromStringCoercion, _checkIntToFloatCoercion, _checkIntToStringCoercion, _checkTextualNull, _checkToStringCoercion, _coerceBooleanFromInt, _coercedTypeDesc, _coerceEmptyString, _coerceIntegral, _coerceNullToken, _coerceTextualNull, _deserializeFromArray, _deserializeFromEmpty, _deserializeFromEmptyString, _deserializeFromString, _deserializeWrappedValue, _failDoubleToIntCoercion, _findCoercionFromBlankString, _findCoercionFromEmptyArray, _findCoercionFromEmptyString, _findNullProvider, _hasTextualNull, _intOverflow, _isBlank, _isEmptyOrTextualNull, _isFalse, _isIntNumber, _isNaN, _isNegInf, _isPosInf, _isTrue, _neitherNull, _nonNullNumber, _parseBoolean, _parseBooleanFromInt, _parseBooleanPrimitive, _parseBooleanPrimitive, _parseBytePrimitive, _parseDate, _parseDate, _parseDateFromArray, _parseDouble, _parseDouble, _parseDoublePrimitive, _parseDoublePrimitive, _parseDoublePrimitive, _parseFloatPrimitive, _parseFloatPrimitive, _parseFloatPrimitive, _parseInteger, _parseInteger, _parseIntPrimitive, _parseIntPrimitive, _parseLong, _parseLong, _parseLongPrimitive, _parseLongPrimitive, _parseShortPrimitive, _parseString, _parseString, _reportFailedNullCoerce, _shortOverflow, _verifyEndArrayForSingle, _verifyNullForPrimitive, _verifyNullForPrimitiveCoercion, _verifyNullForScalarCoercion, _verifyNumberForScalarCoercion, _verifyStringForScalarCoercion, findContentNullProvider, findContentNullStyle, findConvertingContentDeserializer, findDeserializer, findFormatFeature, findFormatOverrides, findValueNullProvider, getValueClass, getValueInstantiator, getValueType, getValueType, handleMissingEndArrayForSingle, handleNestedArrayForSingle, handleUnknownProperty, isDefaultDeserializer, isDefaultKeyDeserializer

Methods inherited from class com.fasterxml.jackson.databind.JsonDeserializer
deserializeWithType, findBackReference, getAbsentValue, getEmptyAccessPattern, getEmptyValue, getEmptyValue, getKnownPropertyNames, getNullAccessPattern, getNullValue, getNullValue, getObjectIdReader, isCachable, replaceDelegatee, unwrappingDeserializer

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - _converter
```
protected final Converter<Object,T> _converter
```
    Converter that was used for creating _delegateDeserializer.
  - _delegateType
```
protected final JavaType _delegateType
```
    Fully resolved delegate type, with generic information if any available.
  - _delegateDeserializer
```
protected final JsonDeserializer<Object> _delegateDeserializer
```
    Underlying serializer for type T.
- Constructor Detail
  - StdDelegatingDeserializer
```
public StdDelegatingDeserializer(Converter<?,T> converter)
```
  - StdDelegatingDeserializer
```
public StdDelegatingDeserializer(Converter<Object,T> converter,
                                 JavaType delegateType,
                                 JsonDeserializer<?> delegateDeserializer)
```
  - StdDelegatingDeserializer
```
protected StdDelegatingDeserializer(StdDelegatingDeserializer<T> src)
```
    Since:
    
    2.5
- Method Detail
  - withDelegate
```
protected StdDelegatingDeserializer<T> withDelegate(Converter<Object,T> converter,
                                                    JavaType delegateType,
                                                    JsonDeserializer<?> delegateDeserializer)
```
    Method used for creating resolved contextual instances. Must be overridden when sub-classing.
  - resolve
```
public void resolve(DeserializationContext ctxt)
             throws JsonMappingException
```
    Description copied from interface: ResolvableDeserializer
    
    Method called after deserializer instance has been constructed (and registered as necessary by provider objects), but before it has returned it to the caller. Called object can then resolve its dependencies to other types, including self-references (direct or indirect).
    
    Specified by:
    
    resolve in interface ResolvableDeserializer
    
    Parameters:
    
    ctxt - Context to use for accessing configuration, resolving secondary deserializers
    
    Throws:
    
    JsonMappingException
  - createContextual
```
public JsonDeserializer<?> createContextual(DeserializationContext ctxt,
                                            BeanProperty property)
                                     throws JsonMappingException
```
    Description copied from interface: ContextualDeserializer
    
    Method called to see if a different (or differently configured) deserializer is needed to deserialize values of specified property. Note that instance that this method is called on is typically shared one and as a result method should NOT modify this instance but rather construct and return a new instance. This instance should only be returned as-is, in case it is already suitable for use.
    
    Specified by:
    
    createContextual in interface ContextualDeserializer
    
    Parameters:
    
    ctxt - Deserialization context to access configuration, additional deserializers that may be needed by this deserializer
    
    property - Method, field or constructor parameter that represents the property (and is used to assign deserialized value). Should be available; but there may be cases where caller cannot provide it and null is passed instead (in which case impls usually pass 'this' deserializer as is)
    
    Returns:
    
    Deserializer to use for deserializing values of specified property; may be this instance or a new instance.
    
    Throws:
    
    JsonMappingException
  - getDelegatee
```
public JsonDeserializer<?> getDelegatee()
```
    Description copied from class: JsonDeserializer
    
    Accessor that can be used to determine if this deserializer uses another deserializer for actual deserialization, by delegating calls. If so, will return immediate delegate (which itself may delegate to further deserializers); otherwise will return null.
    
    Overrides:
    
    getDelegatee in class JsonDeserializer<T>
    
    Returns:
    
    Deserializer this deserializer delegates calls to, if null; null otherwise.
  - handledType
```
public Class<?> handledType()
```
    Description copied from class: JsonDeserializer
    
    Method for accessing concrete physical type of values this deserializer produces. Note that this information is not guaranteed to be exact -- it may be a more generic (super-type) -- but it should not be incorrect (return a non-related type).
    Default implementation will return null, which means almost same same as returning Object.class would; that is, that nothing is known about handled type.
    
    Overrides:
    
    handledType in class StdDeserializer<T>
    
    Returns:
    
    Physical type of values this deserializer produces, if known; null if not
  - logicalType
```
public LogicalType logicalType()
```
    Description copied from class: JsonDeserializer
    
    Method for accessing logical type of values this deserializer produces. Typically used for further configuring handling of values, for example, to find which coercions are legal.
    
    Overrides:
    
    logicalType in class JsonDeserializer<T>
    
    Returns:
    
    Logical type of values this deserializer produces, if known; null if not
  - supportsUpdate
```
public Boolean supportsUpdate(DeserializationConfig config)
```
    Description copied from class: JsonDeserializer
    
    Introspection method that may be called to see whether deserializer supports update of an existing value (aka "merging") or not. Return value should either be Boolean.FALSE if update is not supported at all (immutable values); Boolean.TRUE if update should usually work (regular POJOs, for example), or null if this is either not known, or may sometimes work.
    Information gathered is typically used to either prevent merging update for property (either by skipping, if based on global defaults; or by exception during deserializer construction if explicit attempt made) if Boolean.FALSE returned, or inclusion if Boolean.TRUE is specified. If "unknown" case (null returned) behavior is to exclude property if global defaults used; or to allow if explicit per-type or property merging is defined.
    Default implementation returns null to allow explicit per-type or per-property attempts.
    
    Overrides:
    
    supportsUpdate in class JsonDeserializer<T>
  - deserialize
```
public T deserialize(com.fasterxml.jackson.core.JsonParser p,
                     DeserializationContext ctxt)
              throws IOException
```
    Description copied from class: JsonDeserializer
    Method that can be called to ask implementation to deserialize JSON content into the value type this serializer handles. Returned instance is to be constructed by method itself.
    Pre-condition for this method is that the parser points to the first event that is part of value to deserializer (and which is never JSON 'null' literal, more on this below): for simple types it may be the only value; and for structured types the Object start marker or a FIELD_NAME.
    
    The two possible input conditions for structured types result from polymorphism via fields. In the ordinary case, Jackson calls this method when it has encountered an OBJECT_START, and the method implementation must advance to the next token to see the first field name. If the application configures polymorphism via a field, then the object looks like the following.
```
      {
          "@class": "class name",
          ...
      }
  
```
    Jackson consumes the two tokens (the @class field name and its value) in order to learn the class and select the deserializer. Thus, the stream is pointing to the FIELD_NAME for the first field after the @class. Thus, if you want your method to work correctly both with and without polymorphism, you must begin your method with:
```
       if (p.currentToken() == JsonToken.START_OBJECT) {
         p.nextToken();
       }
  
```
    This results in the stream pointing to the field name, so that the two conditions align.
    Post-condition is that the parser will point to the last event that is part of deserialized value (or in case deserialization fails, event that was not recognized or usable, which may be the same event as the one it pointed to upon call).
    Note that this method is never called for JSON null literal, and thus deserializers need (and should) not check for it.
    Specified by:
    
    deserialize in class JsonDeserializer<T>
    
    Parameters:
    
    p - Parsed used for reading JSON content
    
    ctxt - Context that can be used to access information about this deserialization activity.
    
    Returns:
    
    Deserialized value
    
    Throws:
    
    IOException
  - deserializeWithType
```
public Object deserializeWithType(com.fasterxml.jackson.core.JsonParser p,
                                  DeserializationContext ctxt,
                                  TypeDeserializer typeDeserializer)
                           throws IOException
```
    Description copied from class: StdDeserializer
    
    Base implementation that does not assume specific type inclusion mechanism. Sub-classes are expected to override this method if they are to handle type information.
    
    Overrides:
    
    deserializeWithType in class StdDeserializer<T>
    
    typeDeserializer - Deserializer to use for handling type information
    
    Throws:
    
    IOException
  - deserialize
```
public T deserialize(com.fasterxml.jackson.core.JsonParser p,
                     DeserializationContext ctxt,
                     Object intoValue)
              throws IOException
```
    Description copied from class: JsonDeserializer
    
    Alternate deserialization method (compared to the most commonly used, JsonDeserializer.deserialize(JsonParser, DeserializationContext)), which takes in initialized value instance, to be configured and/or populated by deserializer. Method is not necessarily used (or supported) by all types (it will not work for immutable types, for obvious reasons): most commonly it is used for Collections and Maps. It may be used both with "updating readers" (for POJOs) and when Collections and Maps use "getter as setter".
    Default implementation just throws UnsupportedOperationException, to indicate that types that do not explicitly add support do not necessarily support update-existing-value operation (esp. immutable types)
    
    Overrides:
    
    deserialize in class JsonDeserializer<T>
    
    Throws:
    
    IOException
  - _handleIncompatibleUpdateValue
```
protected Object _handleIncompatibleUpdateValue(com.fasterxml.jackson.core.JsonParser p,
                                                DeserializationContext ctxt,
                                                Object intoValue)
                                         throws IOException
```
    Overridable handler method called when deserialize(JsonParser, DeserializationContext, Object) has been called with a value that is not compatible with delegate value. Since no conversion are expected for such "updateValue" case, this is normally not an operation that can be permitted, and the default behavior is to throw exception. Sub-classes may choose to try alternative approach if they have more information on exact usage and constraints.
    
    Throws:
    
    IOException
    
    Since:
    
    2.6
  - convertValue
```
protected T convertValue(Object delegateValue)
```
    Method called to convert from "delegate value" (which was deserialized from JSON using standard Jackson deserializer for delegate type) into desired target type.
    The default implementation uses configured Converter to do conversion.
    
    Parameters:
    
    delegateValue -
    
    Returns:
    
    Result of conversion

Class StdDelegatingDeserializer<T>

Nested Class Summary

Nested classes/interfaces inherited from class com.fasterxml.jackson.databind.JsonDeserializer

Field Summary

Fields inherited from class com.fasterxml.jackson.databind.deser.std.StdDeserializer

Constructor Summary

Method Summary

Methods inherited from class com.fasterxml.jackson.databind.deser.std.StdDeserializer

Methods inherited from class com.fasterxml.jackson.databind.JsonDeserializer

Methods inherited from class java.lang.Object

Field Detail

_converter

_delegateType

_delegateDeserializer

Constructor Detail

StdDelegatingDeserializer

StdDelegatingDeserializer

StdDelegatingDeserializer

Method Detail

withDelegate

resolve

createContextual

getDelegatee

handledType

logicalType

supportsUpdate

deserialize

deserializeWithType

deserialize

_handleIncompatibleUpdateValue

convertValue