StdDelegatingSerializer.java
package com.fasterxml.jackson.databind.ser.std;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatVisitable;
import com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatVisitorWrapper;
import com.fasterxml.jackson.databind.jsontype.TypeSerializer;
import com.fasterxml.jackson.databind.ser.ContextualSerializer;
import com.fasterxml.jackson.databind.ser.ResolvableSerializer;
import com.fasterxml.jackson.databind.util.ClassUtil;
import com.fasterxml.jackson.databind.util.Converter;
import java.io.IOException;
import java.lang.reflect.Type;
/**
* Serializer implementation where given Java type is first converted
* to an intermediate "delegate type" (using a configured
* {@link Converter}, and then this delegate value is serialized by Jackson.
*<p>
* Note that although types may be related, they must not be same; trying
* to do this will result in an exception.
*
* @since 2.1
*/
@SuppressWarnings("serial")
public class StdDelegatingSerializer
extends StdSerializer<Object>
implements ContextualSerializer, ResolvableSerializer,
JsonFormatVisitable
{
protected final Converter<Object,?> _converter;
/**
* Fully resolved delegate type, with generic information if any available.
*/
protected final JavaType _delegateType;
/**
* Underlying serializer for type <code>T</code>.
*/
protected final JsonSerializer<Object> _delegateSerializer;
/*
/**********************************************************
/* Life-cycle
/**********************************************************
*/
@SuppressWarnings("unchecked")
public StdDelegatingSerializer(Converter<?,?> converter)
{
super(Object.class);
_converter = (Converter<Object,?>)converter;
_delegateType = null;
_delegateSerializer = null;
}
@SuppressWarnings("unchecked")
public <T> StdDelegatingSerializer(Class<T> cls, Converter<T,?> converter)
{
super(cls, false);
_converter = (Converter<Object,?>)converter;
_delegateType = null;
_delegateSerializer = null;
}
@SuppressWarnings("unchecked")
public StdDelegatingSerializer(Converter<Object,?> converter,
JavaType delegateType, JsonSerializer<?> delegateSerializer)
{
super(delegateType);
_converter = converter;
_delegateType = delegateType;
_delegateSerializer = (JsonSerializer<Object>) delegateSerializer;
}
/**
* Method used for creating resolved contextual instances. Must be
* overridden when sub-classing.
*/
protected StdDelegatingSerializer withDelegate(Converter<Object,?> converter,
JavaType delegateType, JsonSerializer<?> delegateSerializer)
{
ClassUtil.verifyMustOverride(StdDelegatingSerializer.class, this, "withDelegate");
return new StdDelegatingSerializer(converter, delegateType, delegateSerializer);
}
/*
/**********************************************************
/* Contextualization
/**********************************************************
*/
@Override
public void resolve(SerializerProvider provider) throws JsonMappingException
{
if ((_delegateSerializer != null)
&& (_delegateSerializer instanceof ResolvableSerializer)) {
((ResolvableSerializer) _delegateSerializer).resolve(provider);
}
}
@Override
public JsonSerializer<?> createContextual(SerializerProvider provider, BeanProperty property)
throws JsonMappingException
{
JsonSerializer<?> delSer = _delegateSerializer;
JavaType delegateType = _delegateType;
if (delSer == null) {
// Otherwise, need to locate serializer to delegate to. For that we need type information...
if (delegateType == null) {
delegateType = _converter.getOutputType(provider.getTypeFactory());
}
// 02-Apr-2015, tatu: For "dynamic case", where type is only specified as
// java.lang.Object (or missing generic), [databind#731]
if (!delegateType.isJavaLangObject()) {
delSer = provider.findValueSerializer(delegateType);
}
}
if (delSer instanceof ContextualSerializer) {
delSer = provider.handleSecondaryContextualization(delSer, property);
}
if (delSer == _delegateSerializer && delegateType == _delegateType) {
return this;
}
return withDelegate(_converter, delegateType, delSer);
}
/*
/**********************************************************
/* Accessors
/**********************************************************
*/
protected Converter<Object, ?> getConverter() {
return _converter;
}
@Override
public JsonSerializer<?> getDelegatee() {
return _delegateSerializer;
}
/*
/**********************************************************
/* Serialization
/**********************************************************
*/
@Override
public void serialize(Object value, JsonGenerator gen, SerializerProvider provider) throws IOException
{
Object delegateValue = convertValue(value);
// should we accept nulls?
if (delegateValue == null) {
provider.defaultSerializeNull(gen);
return;
}
// 02-Apr-2015, tatu: As per [databind#731] may need to do dynamic lookup
JsonSerializer<Object> ser = _delegateSerializer;
if (ser == null) {
ser = _findSerializer(delegateValue, provider);
}
ser.serialize(delegateValue, gen, provider);
}
@Override
public void serializeWithType(Object value, JsonGenerator gen, SerializerProvider provider,
TypeSerializer typeSer) throws IOException
{
// 03-Oct-2012, tatu: This is actually unlikely to work ok... but for now,
// let's give it a chance?
Object delegateValue = convertValue(value);
JsonSerializer<Object> ser = _delegateSerializer;
if (ser == null) {
ser = _findSerializer(value, provider);
}
ser.serializeWithType(delegateValue, gen, provider, typeSer);
}
@Override
public boolean isEmpty(SerializerProvider prov, Object value)
{
Object delegateValue = convertValue(value);
if (delegateValue == null) {
return true;
}
if (_delegateSerializer == null) { // best we can do for now, too costly to look up
return (value == null);
}
return _delegateSerializer.isEmpty(prov, delegateValue);
}
/*
/**********************************************************
/* Schema functionality
/**********************************************************
*/
/**
* @deprecated Since 2.15
*/
@Deprecated
@Override
public JsonNode getSchema(SerializerProvider provider, Type typeHint)
throws JsonMappingException
{
if (_delegateSerializer instanceof com.fasterxml.jackson.databind.jsonschema.SchemaAware) {
return ((com.fasterxml.jackson.databind.jsonschema.SchemaAware) _delegateSerializer)
.getSchema(provider, typeHint);
}
return super.getSchema(provider, typeHint);
}
/**
* @deprecated Since 2.15
*/
@Deprecated
@Override
public JsonNode getSchema(SerializerProvider provider, Type typeHint,
boolean isOptional) throws JsonMappingException
{
if (_delegateSerializer instanceof com.fasterxml.jackson.databind.jsonschema.SchemaAware) {
return ((com.fasterxml.jackson.databind.jsonschema.SchemaAware) _delegateSerializer)
.getSchema(provider, typeHint, isOptional);
}
return super.getSchema(provider, typeHint);
}
@Override
public void acceptJsonFormatVisitor(JsonFormatVisitorWrapper visitor, JavaType typeHint)
throws JsonMappingException
{
/* 03-Sep-2012, tatu: Not sure if this can be made to really work
* properly... but for now, try this:
*/
// 02-Apr-2015, tatu: For dynamic case, very little we can do
if (_delegateSerializer != null) {
_delegateSerializer.acceptJsonFormatVisitor(visitor, typeHint);
}
}
/*
/**********************************************************
/* Overridable methods
/**********************************************************
*/
/**
* Method called to convert from source Java value into delegate
* value (which will be serialized using standard Jackson serializer for delegate type)
*<P>
* The default implementation uses configured {@link Converter} to do
* conversion.
*
* @param value Value to convert
*
* @return Result of conversion
*/
protected Object convertValue(Object value) {
return _converter.convert(value);
}
/**
* Helper method used for locating serializer to use in dynamic use case, where
* actual type value gets converted to is not specified beyond basic
* {@link java.lang.Object}, and where serializer needs to be located dynamically
* based on actual value type.
*
* @since 2.6
*/
protected JsonSerializer<Object> _findSerializer(Object value, SerializerProvider serializers)
throws JsonMappingException
{
// NOTE: will NOT call contextualization
return serializers.findValueSerializer(value.getClass());
}
}