com.fasterxml.jackson.databind.deser.std

Class CollectionDeserializer

java.lang.Object

com.fasterxml.jackson.databind.JsonDeserializer<T>

com.fasterxml.jackson.databind.deser.std.StdDeserializer<T>

com.fasterxml.jackson.databind.deser.std.ContainerDeserializerBase<java.util.Collection<java.lang.Object>>

com.fasterxml.jackson.databind.deser.std.CollectionDeserializer

All Implemented Interfaces:

ContextualDeserializer, NullValueProvider, ValueInstantiator.Gettable, java.io.Serializable

Direct Known Subclasses:

ArrayBlockingQueueDeserializer

public class CollectionDeserializer
extends ContainerDeserializerBase<java.util.Collection<java.lang.Object>>
implements ContextualDeserializer

Basic serializer that can take JSON "Array" structure and construct a Collection instance, with typed contents.

Note: for untyped content (one indicated by passing Object.class as the type), UntypedObjectDeserializer is used instead. It can also construct Lists, but not with specific POJO types, only other containers and primitives/wrappers.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	CollectionDeserializer.CollectionReferringAccumulator Helper class for dealing with Object Id references for values contained in collections being deserialized.

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

JsonDeserializer.None

Constructor Summary

Constructors

Constructor and Description
CollectionDeserializer(JavaType collectionType, JsonDeserializer<java.lang.Object> valueDeser, TypeDeserializer valueTypeDeser, ValueInstantiator valueInstantiator) Constructor for context-free instances, where we do not yet know which property is using this deserializer.

Method Summary

Modifier and Type	Method and Description
CollectionDeserializer	createContextual(DeserializationContext ctxt, BeanProperty property) Method called to finalize setup of this deserializer, when it is known for which property deserializer is needed for.
java.util.Collection<java.lang.Object>	deserialize(JsonParser p, DeserializationContext ctxt) Method that can be called to ask implementation to deserialize JSON content into the value type this serializer handles.
java.util.Collection<java.lang.Object>	deserialize(JsonParser p, DeserializationContext ctxt, java.util.Collection<java.lang.Object> result) 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.
java.lang.Object	deserializeWithType(JsonParser p, DeserializationContext ctxt, TypeDeserializer typeDeserializer) Base implementation that does not assume specific type inclusion mechanism.
JsonDeserializer<java.lang.Object>	getContentDeserializer() Accesor for deserializer use for deserializing content values.
ValueInstantiator	getValueInstantiator()
boolean	isCachable() Method called to see if deserializer instance is cachable and usable for other properties of same type (type for which instance was created).

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

findBackReference, getContentType, getEmptyAccessPattern, getEmptyValue, getValueType, supportsUpdate

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

getValueClass, getValueType, handledType

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

deserializeWithType, getDelegatee, getEmptyValue, getKnownPropertyNames, getNullAccessPattern, getNullValue, getNullValue, getObjectIdReader, replaceDelegatee, unwrappingDeserializer

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CollectionDeserializer

public CollectionDeserializer(JavaType collectionType,
                              JsonDeserializer<java.lang.Object> valueDeser,
                              TypeDeserializer valueTypeDeser,
                              ValueInstantiator valueInstantiator)

Constructor for context-free instances, where we do not yet know which property is using this deserializer.

Method Detail

isCachable

public boolean isCachable()

Description copied from class: JsonDeserializer

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 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.

Overrides:

isCachable in class JsonDeserializer<java.util.Collection<java.lang.Object>>

createContextual

public CollectionDeserializer createContextual(DeserializationContext ctxt,
                                               BeanProperty property)
                                        throws JsonMappingException

Method called to finalize setup of this deserializer, when it is known for which property deserializer is needed for.

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

getContentDeserializer

public JsonDeserializer<java.lang.Object> getContentDeserializer()

Description copied from class: ContainerDeserializerBase

Accesor for deserializer use for deserializing content values.

Specified by:

getContentDeserializer in class ContainerDeserializerBase<java.util.Collection<java.lang.Object>>

getValueInstantiator

public ValueInstantiator getValueInstantiator()

Specified by:

getValueInstantiator in interface ValueInstantiator.Gettable

Overrides:

getValueInstantiator in class ContainerDeserializerBase<java.util.Collection<java.lang.Object>>

deserialize

public java.util.Collection<java.lang.Object> deserialize(JsonParser p,
                                                          DeserializationContext ctxt)
                                                   throws java.io.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<java.util.Collection<java.lang.Object>>

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:

java.io.IOException

deserialize

public java.util.Collection<java.lang.Object> deserialize(JsonParser p,
                                                          DeserializationContext ctxt,
                                                          java.util.Collection<java.lang.Object> result)
                                                   throws java.io.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<java.util.Collection<java.lang.Object>>

Throws:

java.io.IOException

deserializeWithType

public java.lang.Object deserializeWithType(JsonParser p,
                                            DeserializationContext ctxt,
                                            TypeDeserializer typeDeserializer)
                                     throws java.io.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<java.util.Collection<java.lang.Object>>

typeDeserializer - Deserializer to use for handling type information

Throws:

java.io.IOException