Module tools.jackson.databind
Package tools.jackson.databind.deser.jdk

Class CollectionDeserializer

java.lang.Object
tools.jackson.databind.ValueDeserializer<T>
tools.jackson.databind.deser.std.StdDeserializer<T>
tools.jackson.databind.deser.std.ContainerDeserializerBase<Collection<Object>>
tools.jackson.databind.deser.jdk.CollectionDeserializer
All Implemented Interfaces:
NullValueProvider, ValueInstantiator.Gettable
Direct Known Subclasses:
ArrayBlockingQueueDeserializer
public class CollectionDeserializer extends ContainerDeserializerBase<Collection<Object>>
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.

  • Field Details

    • _valueDeserializer

      protected final ValueDeserializer<Object> _valueDeserializer
      Value deserializer.

    • _valueTypeDeserializer

      protected final TypeDeserializer _valueTypeDeserializer
      If element instances have polymorphic type information, this is the type deserializer that can handle it

    • _valueInstantiator

      protected final ValueInstantiator _valueInstantiator

    • _delegateDeserializer

      protected final ValueDeserializer<Object> _delegateDeserializer
      Deserializer that is used iff delegate-based creator is to be used for deserializing from JSON Object.

  • Constructor Details

  • Method Details

    • withResolved

      protected CollectionDeserializer withResolved(ValueDeserializer<?> dd, ValueDeserializer<?> vd, TypeDeserializer vtd, NullValueProvider nuller, Boolean unwrapSingle)
      Fluent-factory method call to construct contextual instance.

    • isCachable

      public boolean isCachable()
      Description copied from class: ValueDeserializer
      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 contextualized on per-property basis (but note that ValueDeserializer.resolve(DeserializationContext)d just once!) 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 ValueDeserializer<Collection<Object>>

    • logicalType

      public LogicalType logicalType()
      Description copied from class: ValueDeserializer
      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 ValueDeserializer<Collection<Object>>
      Returns:
      Logical type of values this deserializer produces, if known; null if not

    • createContextual

      public 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.
      Overrides:
      createContextual in class ValueDeserializer<Collection<Object>>
      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.

    • getContentDeserializer

      public ValueDeserializer<Object> getContentDeserializer()
      Description copied from class: ContainerDeserializerBase
      Accesor for deserializer use for deserializing content values.
      Specified by:
      getContentDeserializer in class ContainerDeserializerBase<Collection<Object>>

    • getValueInstantiator

      public ValueInstantiator getValueInstantiator()
      Specified by:
      getValueInstantiator in interface ValueInstantiator.Gettable
      Overrides:
      getValueInstantiator in class StdDeserializer<Collection<Object>>

    • deserialize

      public Collection<Object> deserialize(tools.jackson.core.JsonParser p, DeserializationContext ctxt) throws tools.jackson.core.JacksonException
      Description copied from class: ValueDeserializer
      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).

      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 ValueDeserializer.getNullValue(DeserializationContext) method is called to produce a null value. To influence null handling, custom deserializers should override ValueDeserializer.getNullValue(DeserializationContext) and usually also ValueDeserializer.getNullAccessPattern().

      Specified by:
      deserialize in class ValueDeserializer<Collection<Object>>
      Parameters:
      p - Parser used for reading JSON content
      ctxt - Context that can be used to access information about this deserialization activity.
      Returns:
      Deserialized value
      Throws:
      tools.jackson.core.JacksonException

    • createDefaultInstance

      protected Collection<Object> createDefaultInstance(DeserializationContext ctxt) throws tools.jackson.core.JacksonException
      Throws:
      tools.jackson.core.JacksonException

    • deserialize

      public Collection<Object> deserialize(tools.jackson.core.JsonParser p, DeserializationContext ctxt, Collection<Object> result) throws tools.jackson.core.JacksonException
      Description copied from class: ValueDeserializer
      Alternate deserialization method (compared to the most commonly used, ValueDeserializer.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 ValueDeserializer<Collection<Object>>
      Throws:
      tools.jackson.core.JacksonException

    • deserializeWithType

      public Object deserializeWithType(tools.jackson.core.JsonParser p, DeserializationContext ctxt, TypeDeserializer typeDeserializer) throws tools.jackson.core.JacksonException
      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<Collection<Object>>
      typeDeserializer - Deserializer to use for handling type information
      Throws:
      tools.jackson.core.JacksonException

    • _deserializeFromString

      protected Collection<Object> _deserializeFromString(tools.jackson.core.JsonParser p, DeserializationContext ctxt, String value) throws tools.jackson.core.JacksonException
      Logic extracted to deal with incoming String value.
      Throws:
      tools.jackson.core.JacksonException
      Since:
      2.12

    • _deserializeFromArray

      protected Collection<Object> _deserializeFromArray(tools.jackson.core.JsonParser p, DeserializationContext ctxt, Collection<Object> result) throws tools.jackson.core.JacksonException
      Throws:
      tools.jackson.core.JacksonException
      Since:
      2.12

    • handleNonArray

      protected final Collection<Object> handleNonArray(tools.jackson.core.JsonParser p, DeserializationContext ctxt, Collection<Object> result) throws tools.jackson.core.JacksonException
      Helper method called when current token is no START_ARRAY. Will either throw an exception, or try to handle value as if member of implicit array, depending on configuration.
      Throws:
      tools.jackson.core.JacksonException

    • _deserializeWithObjectId

      protected Collection<Object> _deserializeWithObjectId(tools.jackson.core.JsonParser p, DeserializationContext ctxt, Collection<Object> result) throws tools.jackson.core.JacksonException
      Throws:
      tools.jackson.core.JacksonException

    • _tryToAddNull

      protected void _tryToAddNull(tools.jackson.core.JsonParser p, DeserializationContext ctxt, Collection<?> set)
      java.util.TreeSet (and possibly other Collection types) does not allow addition of null values, so isolate handling here.