public Class AbstractDeserializer

Parameters

props:Map<String, SettableBeanProperty>

Regular properties: currently only needed to support property-annotated Object Id handling with property inclusion (needed for determining type of Object Id to bind)

Since

2.9

Annotations

@Deprecated

Factory method used when constructing instances for non-POJO types, like java.util.Maps.

Since

2.3

Implements com.fasterxml.jackson.databind.deser.ContextualDeserializer.createContextual.

Doc from com.fasterxml.jackson.databind.deser.ContextualDeserializer.createContextual.

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.

Parameters

ctxt:DeserializationContext

Deserialization context to access configuration, additional deserializers that may be needed by this deserializer

property:BeanProperty

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:JsonDeserializer<?>

Deserializer to use for deserializing values of specified property; may be this instance or a new instance.

Annotations

@Override

Implements abstract com.fasterxml.jackson.databind.JsonDeserializer.deserialize.

Doc from com.fasterxml.jackson.databind.JsonDeserializer.deserialize.

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",
          ...
      }
  

       if (p.currentToken() == JsonToken.START_OBJECT) {
         p.nextToken();
       }
  

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).

Handling null values (JsonToken.VALUE_NULL)
: Note that this method is never called for the JSON null literal to avoid every deserializer from having to handle null values. Instead, the JsonDeserializer#getNullValue(DeserializationContext) method is called to produce a null value. To influence null handling, custom deserializers should override JsonDeserializer#getNullValue(DeserializationContext) and usually also JsonDeserializer#getNullAccessPattern().

Parameters

p:JsonParser

Parser used for reading JSON content

ctxt:DeserializationContext

Context that can be used to access information about this deserialization activity.

Returns:Object

Deserialized value

Annotations

@Override

Overrides com.fasterxml.jackson.databind.JsonDeserializer.deserializeWithType.

Doc from com.fasterxml.jackson.databind.JsonDeserializer.deserializeWithType.

Deserialization called when type being deserialized is defined to contain additional type identifier, to allow for correctly instantiating correct subtype. This can be due to annotation on type (or its supertype), or due to global settings without annotations.

Default implementation may work for some types, but ideally subclasses should not rely on current default implementation. Implementation is mostly provided to avoid compilation errors with older code.

Parameters

typeDeserializer:TypeDeserializer

Deserializer to use for handling type information

Annotations

@Override

Overrides com.fasterxml.jackson.databind.JsonDeserializer.findBackReference.

Method called by BeanDeserializer to resolve back reference part of managed references.

Annotations

@Override

Overrides com.fasterxml.jackson.databind.JsonDeserializer.getObjectIdReader.

Overridden to return true for those instances that are handling value for which Object Identity handling is enabled (either via value type or referring property).

Returns:ObjectIdReader

Doc from com.fasterxml.jackson.databind.JsonDeserializer.getObjectIdReader.

ObjectIdReader used for resolving possible Object Identifier value, instead of full value serialization, if deserializer can do that; null if no Object Id is expected.

Annotations

@Override

Overrides com.fasterxml.jackson.databind.JsonDeserializer.handledType.

Doc from com.fasterxml.jackson.databind.JsonDeserializer.handledType.

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.

Returns:Class<?>

Physical type of values this deserializer produces, if known; null if not

Annotations

@Override

Overrides com.fasterxml.jackson.databind.JsonDeserializer.isCachable.

Doc from com.fasterxml.jackson.databind.JsonDeserializer.isCachable.

Method called to see if deserializer instance is cachable and usable for other properties of same type (type for which instance was created).

Note that cached instances are still resolved on per-property basis, if instance implements com.fasterxml.jackson.databind.deser.ResolvableDeserializer: cached instance is just as the base. This means that in most cases it is safe to cache instances; however, it only makes sense to cache instances if instantiation is expensive, or if instances are heavy-weight.

Default implementation returns false, to indicate that no caching is done.

Annotations

@Override

Overrides com.fasterxml.jackson.databind.JsonDeserializer.logicalType.

Doc from com.fasterxml.jackson.databind.JsonDeserializer.logicalType.

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.

Returns:LogicalType

Logical type of values this deserializer produces, if known; null if not

Annotations

@Override

Overrides com.fasterxml.jackson.databind.JsonDeserializer.supportsUpdate.

Doc from com.fasterxml.jackson.databind.JsonDeserializer.supportsUpdate.

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.

Annotations

@Override