jackson-databind 2.16.0 · com.fasterxml.jackson.databind.JsonSerializer

Abstract class that defines API used by ObjectMapper (and other chained JsonSerializers too) to serialize Objects of arbitrary types into JSON, using provided JsonGenerator. com.fasterxml.jackson.databind.ser.std.StdSerializer instead of this class, since it will implement many of optional methods of this class.

Note

various serialize methods are never (to be) called with null values -- caller must handle null values, usually by calling SerializerProvider#findNullValueSerializer to obtain serializer to use. This also means that custom serializers cannot be directly used to change the output to produce when serializing null values.

If serializer is an aggregate one -- meaning it delegates handling of some of its contents by using other serializer(s) -- it typically also needs to implement com.fasterxml.jackson.databind.ser.ResolvableSerializer, which can locate secondary serializers needed. This is important to allow dynamic overrides of serializers; separate call interface is needed to separate resolution of secondary serializers (which may have cyclic link back to serializer itself, directly or indirectly).

In addition, to support per-property annotations (to configure aspects of serialization on per-property basis), serializers may want to implement com.fasterxml.jackson.databind.ser.ContextualSerializer, which allows specialization of serializers: call to com.fasterxml.jackson.databind.ser.ContextualSerializer#createContextual is passed information on property, and can create a newly configured serializer for handling that particular property.

If both com.fasterxml.jackson.databind.ser.ResolvableSerializer and com.fasterxml.jackson.databind.ser.ContextualSerializer are implemented, resolution of serializers occurs before contextualization.

Nested and Inner Type Summary

Modifier and Type	Class and Description
public abstract static class	JsonSerializer.None This marker class is only to be used with annotations, to indicate that no serializer is configured.

Constructor Summary

Access	Constructor and Description
public	JsonSerializer()

Method Summary

Modifier and Type	Method and Description
public void	acceptJsonFormatVisitor(JsonFormatVisitorWrapper visitor, JavaType Type of element (entity like property) being visited type) Implements com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatVisitable.acceptJsonFormatVisitor. Default implementation simply calls `JsonFormatVisitorWrapper#expectAnyFormat(JavaType)`.
public JsonSerializer<?>	Returns: Serializer this serializer delegates calls to, if null; null otherwise. getDelegatee() Accessor that can be used to determine if this serializer uses another serializer for actual serialization, by delegating calls.
public Class<T>	handledType() Method for accessing type of Objects this serializer can handle.
public boolean	isEmpty(T value) Deprecated Since 2.5 Use `isEmpty(SerializerProvider, Object)` instead; will be removed from 3.0 Method called to check whether given serializable value is considered "empty" value (for purposes of suppressing serialization of empty values).
public boolean	isEmpty(SerializerProvider provider, T value) Method called to check whether given serializable value is considered "empty" value (for purposes of suppressing serialization of empty values).
public boolean	isUnwrappingSerializer() 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.
public Iterator<PropertyWriter>	properties() Accessor for iterating over logical properties that the type handled by this serializer has, from serialization perspective.
public JsonSerializer<T>	replaceDelegatee(JsonSerializer<?> delegatee) Method that can be called to try to replace serializer this serializer delegates calls to.
public abstract void	serialize(T Value to serialize; can not be null. value, JsonGenerator Generator used to output resulting Json content gen, SerializerProvider Provider that can be used to get serializers for serializing Objects value contains, if any. serializers) Method that can be called to ask implementation to serialize values of type this serializer handles.
public void	serializeWithType(T Value to serialize; can not be null. value, JsonGenerator Generator used to output resulting Json content gen, SerializerProvider Provider that can be used to get serializers for serializing Objects value contains, if any. serializers, TypeSerializer Type serializer to use for including type information typeSer) 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.
public JsonSerializer<T>	unwrappingSerializer(NameTransformer Name transformation to use to convert between names of unwrapper properties unwrapper) 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).
public boolean	usesObjectId() Method that can be called to see whether this serializer instance will use Object Id to handle cyclic references.
public JsonSerializer<?>	withFilterId(Object filterId) Mutant factory method that is called if contextual configuration indicates that a specific filter (as specified by `filterId`) is to be used for serialization.
public JsonSerializer<?>	Returns: Serializer instance that without specified set of properties to ignore (if any) withIgnoredProperties(Set<String> Set of property names to ignore for serialization; ignoredProperties) Mutant factory method called to create a new instance after excluding specified set of properties by name, if there is any.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Constructor Detail

JsonSerializer	back to summary
public JsonSerializer()

Method Detail

acceptJsonFormatVisitor back to summary

acceptJsonFormatVisitor	back to summary
public void acceptJsonFormatVisitor(JsonFormatVisitorWrapper visitor, JavaType type) throws JsonMappingException Implements com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatVisitable.acceptJsonFormatVisitor. Default implementation simply calls `JsonFormatVisitorWrapper#expectAnyFormat(JavaType)`. Parameters type:JavaType Doc from com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatVisitable.acceptJsonFormatVisitor. Type of element (entity like property) being visited Annotations @Override Since 2.1

public void acceptJsonFormatVisitor(JsonFormatVisitorWrapper visitor, JavaType type) throws JsonMappingException

Implements com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatVisitable.acceptJsonFormatVisitor.

Default implementation simply calls JsonFormatVisitorWrapper#expectAnyFormat(JavaType).

Parameters

type:JavaType

Doc from com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatVisitable.acceptJsonFormatVisitor.

Type of element (entity like property) being visited

Annotations

@Override

Since

2.1

getDelegatee	back to summary
public JsonSerializer<?> getDelegatee() 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. Returns:JsonSerializer<?> Serializer this serializer delegates calls to, if null; null otherwise. Since 2.1

getDelegatee

back to summary

public JsonSerializer<?> getDelegatee()

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.

Returns:JsonSerializer<?>: Serializer this serializer delegates calls to, if null; null otherwise.
Since: 2.1

handledType back to summary

handledType	back to summary
public Class<T> handledType() 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). Default implementation will return null, which essentially means same as returning `Object.class` would; that is, that nothing is known about handled type.

public Class<T> handledType()

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).

Default implementation will return null, which essentially means same as returning Object.class would; that is, that nothing is known about handled type.

isEmpty back to summary

isEmpty	back to summary
public boolean isEmpty(T value) Deprecated Since 2.5 Use `isEmpty(SerializerProvider, Object)` instead; will be removed from 3.0 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. Annotations @Deprecated

public boolean isEmpty(T value)

Deprecated

Since 2.5 Use isEmpty(SerializerProvider, Object) instead; will be removed from 3.0

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.

Annotations

@Deprecated

isEmpty back to summary

isEmpty	back to summary
public boolean isEmpty(SerializerProvider provider, T value) 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. Note replaces `isEmpty(Object)`, which was deprecated in 2.5 Since 2.5

public boolean isEmpty(SerializerProvider provider, T value)

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.

Note

replaces isEmpty(Object), which was deprecated in 2.5

Since: 2.5

isUnwrappingSerializer	back to summary
public boolean isUnwrappingSerializer() 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.

properties back to summary

properties	back to summary
public Iterator<PropertyWriter> properties() 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 `com.fasterxml.jackson.databind.ser.BeanPropertyWriter`. Of standard Jackson serializers, only `com.fasterxml.jackson.databind.ser.BeanSerializer` exposes properties. Since 2.6

public Iterator<PropertyWriter> properties()

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 com.fasterxml.jackson.databind.ser.BeanPropertyWriter. Of standard Jackson serializers, only com.fasterxml.jackson.databind.ser.BeanSerializer exposes properties.

Since: 2.6

replaceDelegatee back to summary

replaceDelegatee	back to summary
public JsonSerializer<T> replaceDelegatee(JsonSerializer<?> delegatee) 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. Since 2.1

public JsonSerializer<T> replaceDelegatee(JsonSerializer<?> delegatee)

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.

Since: 2.1

serialize	back to summary
public abstract void serialize(T value, JsonGenerator gen, SerializerProvider serializers) throws IOException Method that can be called to ask implementation to serialize values of type this serializer handles. Parameters value:T Value to serialize; can not be null. gen:JsonGenerator Generator used to output resulting Json content serializers:SerializerProvider Provider that can be used to get serializers for serializing Objects value contains, if any.

serialize

back to summary

public abstract void serialize(T value, JsonGenerator gen, SerializerProvider serializers) throws IOException

Method that can be called to ask implementation to serialize values of type this serializer handles.

Parameters

value:T: Value to serialize; can not be null.
gen:JsonGenerator: Generator used to output resulting Json content
serializers:SerializerProvider: Provider that can be used to get serializers for serializing Objects value contains, if any.

serializeWithType back to summary

serializeWithType	back to summary
public void serializeWithType(T value, JsonGenerator gen, SerializerProvider serializers, TypeSerializer typeSer) throws IOException 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, provider); 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. Parameters value:T Value to serialize; can not be null. gen:JsonGenerator Generator used to output resulting Json content serializers:SerializerProvider Provider that can be used to get serializers for serializing Objects value contains, if any. typeSer:TypeSerializer Type serializer to use for including type information

public void serializeWithType(T value, JsonGenerator gen, SerializerProvider serializers, TypeSerializer typeSer) throws IOException

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, provider);
  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.

Parameters

value:T: Value to serialize; can not be null.
gen:JsonGenerator: Generator used to output resulting Json content
serializers:SerializerProvider: Provider that can be used to get serializers for serializing Objects value contains, if any.
typeSer:TypeSerializer: Type serializer to use for including type information

unwrappingSerializer	back to summary
public JsonSerializer<T> unwrappingSerializer(NameTransformer unwrapper) 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 Parameters unwrapper:NameTransformer Name transformation to use to convert between names of unwrapper properties

unwrappingSerializer

back to summary

public JsonSerializer<T> unwrappingSerializer(NameTransformer unwrapper)

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

Parameters

unwrapper:NameTransformer: Name transformation to use to convert between names of unwrapper properties

usesObjectId	back to summary
public boolean usesObjectId() Method that can be called to see whether this serializer instance will use Object Id to handle cyclic references.

withFilterId back to summary

withFilterId	back to summary
public JsonSerializer<?> withFilterId(Object filterId) 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. Since 2.6

public JsonSerializer<?> withFilterId(Object filterId)

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.

Since: 2.6

withIgnoredProperties	back to summary
public JsonSerializer<?> withIgnoredProperties(Set<String> ignoredProperties) Mutant factory method called to create a new instance after excluding specified set of properties by name, if there is any. Parameters ignoredProperties:Set<String> Set of property names to ignore for serialization; Returns:JsonSerializer<?> Serializer instance that without specified set of properties to ignore (if any) Since 2.16

withIgnoredProperties

back to summary

public JsonSerializer<?> withIgnoredProperties(Set<String> ignoredProperties)

Mutant factory method called to create a new instance after excluding specified set of properties by name, if there is any.

Parameters

ignoredProperties:Set<String>: Set of property names to ignore for serialization;

Returns:JsonSerializer<?>

Serializer instance that without specified set of properties to ignore (if any)

Since

2.16

public abstract Class JsonSerializer<T>

Nested and Inner Type Summary

Constructor Summary

Method Summary

Constructor Detail

Method Detail

public abstract Class JsonSerializer.None

Constructor Summary

Method Summary

Constructor Detail