Module tools.jackson.databind
Package tools.jackson.databind.ser.std

Class DelegatingSerializer

java.lang.Object
tools.jackson.databind.ValueSerializer<T>
tools.jackson.databind.ser.std.StdSerializer<Object>
tools.jackson.databind.ser.std.DelegatingSerializer
All Implemented Interfaces:
JsonFormatVisitable
public abstract class DelegatingSerializer extends StdSerializer<Object>
Base class that simplifies implementations of ValueSerializers that mostly delegate functionality to another serializer implementation (possibly forming a chaining of serializers delegating functionality in some cases).
Since:
3.1

  • Field Details

  • Constructor Details

    • DelegatingSerializer

      public DelegatingSerializer(ValueSerializer<?> delegatee)

  • Method Details

    • newDelegatingInstance

      protected abstract ValueSerializer<Object> newDelegatingInstance(ValueSerializer<?> newDelegatee)

    • _newIfChanged

      protected final ValueSerializer<Object> _newIfChanged(ValueSerializer<?> newDelegatee)

    • replaceDelegatee

      public ValueSerializer<Object> replaceDelegatee(ValueSerializer<?> delegatee)
      Description copied from class: ValueSerializer
      Method that can be called to try to replace serializer this serializer delegates calls to. If not supported (either this serializer does not delegate anything; or it does not want any changes), should either throw UnsupportedOperationException (if operation does not make sense or is not allowed); or return this serializer as is.
      Overrides:
      replaceDelegatee in class ValueSerializer<Object>

    • unwrappingSerializer

      public ValueSerializer<Object> unwrappingSerializer(NameTransformer unwrapper)
      Description copied from class: ValueSerializer
      Method that will return serializer instance that produces "unwrapped" serialization, if applicable for type being serialized (which is the case for some serializers that produce JSON Objects as output). If no unwrapped serializer can be constructed, will simply return serializer as-is.

      Default implementation just returns serializer as-is, indicating that no unwrapped variant exists

      Overrides:
      unwrappingSerializer in class ValueSerializer<Object>
      Parameters:
      unwrapper - Name transformation to use to convert between names of unwrapper properties

    • withFilterId

      public ValueSerializer<?> withFilterId(Object filterId)
      Description copied from class: ValueSerializer
      Mutant factory method that is called if contextual configuration indicates that a specific filter (as specified by filterId) is to be used for serialization.

      Default implementation simply returns this; sub-classes that do support filtering will need to create and return new instance if filter changes.

      Overrides:
      withFilterId in class ValueSerializer<Object>

    • withFormatOverrides

      public ValueSerializer<?> withFormatOverrides(SerializationConfig config, JsonFormat.Value formatOverrides)
      Description copied from class: ValueSerializer
      Mutant factory called if there is need to create a serializer with specified format overrides (typically from property on which this serializer would be used, based on type declaration). Method is called before ValueSerializer.createContextual(tools.jackson.databind.SerializationContext, tools.jackson.databind.BeanProperty) but right after serializer is either constructed or fetched from cache.

      Method can do one of three things:

      • Return this instance as is: this means that none of overrides has any effect
      • Return an alternate ValueSerializer, suitable for use with specified format
      • Return null to indicate that this serializer instance is not suitable for handling format variation, but does not know how to construct new serializer: caller will typically then call SerializerFactory with overrides to construct new serializer
      One example of second approach is the case where JsonFormat.Shape.STRING indicates String representation and code can just construct simple "string-like serializer", or variant of itself (similar to how ValueSerializer.createContextual(tools.jackson.databind.SerializationContext, tools.jackson.databind.BeanProperty) is often implemented). And third case (returning null) is applicable for cases like format defines JsonFormat.Shape.POJO, requesting "introspect serializer for POJO regardless of type": SerializerFactory is needed for full re-introspection, typically.
      Overrides:
      withFormatOverrides in class ValueSerializer<Object>
      formatOverrides - (not null) Override settings, NOT including original format settings (which serializer needs to explicitly retain if needed)

    • withIgnoredProperties

      public ValueSerializer<?> withIgnoredProperties(Set<String> ignoredProperties)
      Description copied from class: ValueSerializer
      Mutant factory method called to create a new instance after excluding specified set of properties by name, if there is any.
      Overrides:
      withIgnoredProperties in class ValueSerializer<Object>
      Parameters:
      ignoredProperties - Set of property names to ignore for serialization;
      Returns:
      Serializer instance that without specified set of properties to ignore (if any)

    • resolve

      public void resolve(SerializationContext ctxt)
      Description copied from class: ValueSerializer
      Method called after SerializationContext has registered the serializer, 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).

      Note that this method does NOT return serializer, since resolution is not allowed to change actual serializer to use.

      Overrides:
      resolve in class ValueSerializer<Object>
      Parameters:
      ctxt - Currently active serialization context.

    • createContextual

      public ValueSerializer<?> createContextual(SerializationContext ctxt, BeanProperty property)
      Description copied from class: ValueSerializer
      Method called to see if a different (or differently configured) serializer is needed to serialize values of specified property (or, for root values, in which case `null` is passed). 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.

      Note that method is only called once per POJO property, and for the first usage as root value serializer; it is not called for every serialization, as doing that would have significant performance impact; most serializers cache contextual instances for future use.

      Overrides:
      createContextual in class ValueSerializer<Object>
      Parameters:
      ctxt - Context to use for accessing config, other serializers
      property - Property (defined by one or more accessors - field or method - used for accessing logical property value) for which serializer is used to be used; or, `null` for root value (or in cases where caller does not have this information, which is handled as root value case).
      Returns:
      Serializer to use for serializing values of specified property; may be this instance or a new instance.

    • isEmpty

      public boolean isEmpty(SerializationContext ctxt, Object value)
      Description copied from class: ValueSerializer
      Method called to check whether given serializable value is considered "empty" value (for purposes of suppressing serialization of empty values).

      Default implementation will consider only null values to be empty.

      Overrides:
      isEmpty in class ValueSerializer<Object>

    • serialize

      public void serialize(Object value, tools.jackson.core.JsonGenerator gen, SerializationContext ctxt)
      Description copied from class: ValueSerializer
      Method that can be called to ask implementation to serialize values of type this serializer handles.
      Specified by:
      serialize in class StdSerializer<Object>
      Parameters:
      value - Value to serialize; can not be null.
      gen - Generator used to output resulting Json content
      ctxt - Context that can be used to get serializers for serializing Objects value contains, if any.

    • serializeWithType

      public void serializeWithType(Object value, tools.jackson.core.JsonGenerator gen, SerializationContext ctxt, TypeSerializer typeSer)
      Description copied from class: ValueSerializer
      Method that can be called to ask implementation to serialize values of type this serializer handles, using specified type serializer for embedding necessary type information.

      Default implementation will throw UnsupportedOperationException to indicate that proper type handling needs to be implemented.

      For simple datatypes written as a single scalar value (JSON String, Number, Boolean), implementation would look like: 

        // note: method to call depends on whether this type is serialized as JSON scalar, object or Array!
  typeSer.writeTypePrefixForScalar(value, gen);
  serialize(value, gen, ctxt);
  typeSer.writeTypeSuffixForScalar(value, gen);
      and implementations for type serialized as JSON Arrays or Objects would differ slightly, as START-ARRAY/END-ARRAY and START-OBJECT/END-OBJECT pairs need to be properly handled with respect to serializing of contents.
      Overrides:
      serializeWithType in class ValueSerializer<Object>
      Parameters:
      value - Value to serialize; can not be null.
      gen - Generator used to output resulting Json content
      ctxt - Context that can be used to get serializers for serializing Objects value contains, if any.
      typeSer - Type serializer to use for including type information

    • handledType

      public Class<?> handledType()
      Description copied from class: ValueSerializer
      Method for accessing type of Objects this serializer can handle. 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).

      NOTE: starting with 3.0, left abstract.

      Overrides:
      handledType in class StdSerializer<Object>

    • usesObjectId

      public boolean usesObjectId()
      Description copied from class: ValueSerializer
      Method that can be called to see whether this serializer instance will use Object Id to handle cyclic references.
      Overrides:
      usesObjectId in class ValueSerializer<Object>

    • isUnwrappingSerializer

      public boolean isUnwrappingSerializer()
      Description copied from class: ValueSerializer
      Accessor for checking whether this serializer is an "unwrapping" serializer; this is necessary to know since it may also require caller to suppress writing of the leading property name.
      Overrides:
      isUnwrappingSerializer in class ValueSerializer<Object>

    • getDelegatee

      public ValueSerializer<?> getDelegatee()
      Description copied from class: ValueSerializer
      Accessor that can be used to determine if this serializer uses another serializer for actual serialization, by delegating calls. If so, will return immediate delegate (which itself may delegate to further serializers); otherwise will return null.
      Overrides:
      getDelegatee in class ValueSerializer<Object>
      Returns:
      Serializer this serializer delegates calls to, if null; null otherwise.

    • properties

      public Iterator<PropertyWriter> properties()
      Description copied from class: ValueSerializer
      Accessor for iterating over logical properties that the type handled by this serializer has, from serialization perspective. Actual type of properties, if any, will be BeanPropertyWriter. Of standard Jackson serializers, only BeanSerializer exposes properties.
      Overrides:
      properties in class ValueSerializer<Object>

    • acceptJsonFormatVisitor

      public void acceptJsonFormatVisitor(JsonFormatVisitorWrapper visitor, JavaType type)
      Description copied from class: StdSerializer
      Default implementation specifies no format. This behavior is usually overriden by custom serializers.
      Specified by:
      acceptJsonFormatVisitor in interface JsonFormatVisitable
      Overrides:
      acceptJsonFormatVisitor in class StdSerializer<Object>
      type - Type of element (entity like property) being visited