package com.fasterxml.jackson.databind.ser.std;

import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Type;
import java.util.LinkedHashSet;
import java.util.Set;

import com.fasterxml.jackson.annotation.JsonTypeInfo.As;
import com.fasterxml.jackson.core.*;
import com.fasterxml.jackson.core.type.WritableTypeId;
import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.annotation.JacksonStdImpl;
import com.fasterxml.jackson.databind.introspect.AnnotatedMember;
import com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatVisitable;
import com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatVisitorWrapper;
import com.fasterxml.jackson.databind.jsonFormatVisitors.JsonStringFormatVisitor;
import com.fasterxml.jackson.databind.jsonschema.SchemaAware;
import com.fasterxml.jackson.databind.jsontype.TypeIdResolver;
import com.fasterxml.jackson.databind.jsontype.TypeSerializer;
import com.fasterxml.jackson.databind.ser.BeanSerializer;
import com.fasterxml.jackson.databind.ser.ContextualSerializer;
import com.fasterxml.jackson.databind.util.ClassUtil;

Serializer class that can serialize Object that have a JsonValue annotation to indicate that serialization should be done by calling the method annotated, and serializing result it returns.

Implementation note: we will post-process resulting serializer (much like what is done with BeanSerializer) to figure out actual serializers for final types. This must be done from createContextual method, and NOT from constructor; otherwise we could end up with an infinite loop.

/** * Serializer class that can serialize Object that have a * {@link com.fasterxml.jackson.annotation.JsonValue} annotation to * indicate that serialization should be done by calling the method * annotated, and serializing result it returns. *<p> * Implementation note: we will post-process resulting serializer * (much like what is done with {@link BeanSerializer}) * to figure out actual serializers for final types. * This must be done from {@link #createContextual} method, and NOT from constructor; * otherwise we could end up with an infinite loop. */
@SuppressWarnings("serial") @JacksonStdImpl public class JsonValueSerializer extends StdSerializer<Object> implements ContextualSerializer, JsonFormatVisitable, SchemaAware {
Since:2.9
/** * @since 2.9 */
protected final AnnotatedMember _accessor; protected final JsonSerializer<Object> _valueSerializer; protected final BeanProperty _property;
This is a flag that is set in rare (?) cases where this serializer is used for "natural" types (boolean, int, String, double); and where we actually must force type information wrapping, even though one would not normally be added.
/** * This is a flag that is set in rare (?) cases where this serializer * is used for "natural" types (boolean, int, String, double); and where * we actually must force type information wrapping, even though * one would not normally be added. */
protected final boolean _forceTypeInformation; /* /********************************************************** /* Life-cycle /********************************************************** */
Params:
  • ser – Explicit serializer to use, if caller knows it (which occurs if and only if the "value method" was annotated with JsonSerialize.using), otherwise null
Since:2.8 Earlier method took "raw" Method, but that does not work with access to information we need
/** * @param ser Explicit serializer to use, if caller knows it (which * occurs if and only if the "value method" was annotated with * {@link com.fasterxml.jackson.databind.annotation.JsonSerialize#using}), otherwise * null * * @since 2.8 Earlier method took "raw" Method, but that does not work with access * to information we need */
@SuppressWarnings("unchecked") public JsonValueSerializer(AnnotatedMember accessor, JsonSerializer<?> ser) { super(accessor.getType()); _accessor = accessor; _valueSerializer = (JsonSerializer<Object>) ser; _property = null; _forceTypeInformation = true; // gets reconsidered when we are contextualized } @SuppressWarnings("unchecked") public JsonValueSerializer(JsonValueSerializer src, BeanProperty property, JsonSerializer<?> ser, boolean forceTypeInfo) { super(_notNullClass(src.handledType())); _accessor = src._accessor; _valueSerializer = (JsonSerializer<Object>) ser; _property = property; _forceTypeInformation = forceTypeInfo; } @SuppressWarnings("unchecked") private final static Class<Object> _notNullClass(Class<?> cls) { return (cls == null) ? Object.class : (Class<Object>) cls; } public JsonValueSerializer withResolved(BeanProperty property, JsonSerializer<?> ser, boolean forceTypeInfo) { if (_property == property && _valueSerializer == ser && forceTypeInfo == _forceTypeInformation) { return this; } return new JsonValueSerializer(this, property, ser, forceTypeInfo); } /* /********************************************************** /* Post-processing /********************************************************** */
We can try to find the actual serializer for value, if we can statically figure out what the result type must be.
/** * We can try to find the actual serializer for value, if we can * statically figure out what the result type must be. */
@Override public JsonSerializer<?> createContextual(SerializerProvider provider, BeanProperty property) throws JsonMappingException { JsonSerializer<?> ser = _valueSerializer; if (ser == null) { /* Can only assign serializer statically if the declared type is final: * if not, we don't really know the actual type until we get the instance. */ // 10-Mar-2010, tatu: Except if static typing is to be used JavaType t = _accessor.getType(); if (provider.isEnabled(MapperFeature.USE_STATIC_TYPING) || t.isFinal()) { // false -> no need to cache /* 10-Mar-2010, tatu: Ideally we would actually separate out type * serializer from value serializer; but, alas, there's no access * to serializer factory at this point... */ // 05-Sep-2013, tatu: I _think_ this can be considered a primary property... ser = provider.findPrimaryPropertySerializer(t, property); /* 09-Dec-2010, tatu: Turns out we must add special handling for * cases where "native" (aka "natural") type is being serialized, * using standard serializer */ boolean forceTypeInformation = isNaturalTypeWithStdHandling(t.getRawClass(), ser); return withResolved(property, ser, forceTypeInformation); } } else { // 05-Sep-2013, tatu: I _think_ this can be considered a primary property... ser = provider.handlePrimaryContextualization(ser, property); return withResolved(property, ser, _forceTypeInformation); } return this; } /* /********************************************************** /* Actual serialization /********************************************************** */ @Override public void serialize(Object bean, JsonGenerator gen, SerializerProvider prov) throws IOException { try { Object value = _accessor.getValue(bean); if (value == null) { prov.defaultSerializeNull(gen); return; } JsonSerializer<Object> ser = _valueSerializer; if (ser == null) { Class<?> c = value.getClass(); /* 10-Mar-2010, tatu: Ideally we would actually separate out type * serializer from value serializer; but, alas, there's no access * to serializer factory at this point... */ // let's cache it, may be needed soon again ser = prov.findTypedValueSerializer(c, true, _property); } ser.serialize(value, gen, prov); } catch (Exception e) { wrapAndThrow(prov, e, bean, _accessor.getName() + "()"); } } @Override public void serializeWithType(Object bean, JsonGenerator gen, SerializerProvider provider, TypeSerializer typeSer0) throws IOException { // Regardless of other parts, first need to find value to serialize: Object value = null; try { value = _accessor.getValue(bean); // and if we got null, can also just write it directly if (value == null) { provider.defaultSerializeNull(gen); return; } JsonSerializer<Object> ser = _valueSerializer; if (ser == null) { // no serializer yet? Need to fetch ser = provider.findValueSerializer(value.getClass(), _property); } else { // 09-Dec-2010, tatu: To work around natural type's refusal to add type info, we do // this (note: type is for the wrapper type, not enclosed value!) if (_forceTypeInformation) { // Confusing? Type id is for POJO and NOT for value returned by JsonValue accessor... WritableTypeId typeIdDef = typeSer0.writeTypePrefix(gen, typeSer0.typeId(bean, JsonToken.VALUE_STRING)); ser.serialize(value, gen, provider); typeSer0.writeTypeSuffix(gen, typeIdDef); return; } } // 28-Sep-2016, tatu: As per [databind#1385], we do need to do some juggling // to use different Object for type id (logical type) and actual serialization // (delegat type). TypeSerializerRerouter rr = new TypeSerializerRerouter(typeSer0, bean); ser.serializeWithType(value, gen, provider, rr); } catch (Exception e) { wrapAndThrow(provider, e, bean, _accessor.getName() + "()"); } } @SuppressWarnings("deprecation") @Override public JsonNode getSchema(SerializerProvider provider, Type typeHint) throws JsonMappingException { if (_valueSerializer instanceof SchemaAware) { return ((SchemaAware)_valueSerializer).getSchema(provider, null); } return com.fasterxml.jackson.databind.jsonschema.JsonSchema.getDefaultSchemaNode(); } @Override public void acceptJsonFormatVisitor(JsonFormatVisitorWrapper visitor, JavaType typeHint) throws JsonMappingException { /* 27-Apr-2015, tatu: First things first; for JSON Schema introspection, * Enum types that use `@JsonValue` are special (but NOT necessarily * anything else that RETURNS an enum!) * So we will need to add special * handling here (see https://github.com/FasterXML/jackson-module-jsonSchema/issues/57 * for details). * * Note that meaning of JsonValue, then, is very different for Enums. Sigh. */ final JavaType type = _accessor.getType(); Class<?> declaring = _accessor.getDeclaringClass(); if ((declaring != null) && declaring.isEnum()) { if (_acceptJsonFormatVisitorForEnum(visitor, typeHint, declaring)) { return; } } JsonSerializer<Object> ser = _valueSerializer; if (ser == null) { ser = visitor.getProvider().findTypedValueSerializer(type, false, _property); if (ser == null) { // can this ever occur? visitor.expectAnyFormat(typeHint); return; } } ser.acceptJsonFormatVisitor(visitor, type); }
Overridable helper method used for special case handling of schema information for Enums.
Returns:True if method handled callbacks; false if not; in latter case caller will send default callbacks
Since:2.6
/** * Overridable helper method used for special case handling of schema information for * Enums. * * @return True if method handled callbacks; false if not; in latter case caller will * send default callbacks * * @since 2.6 */
protected boolean _acceptJsonFormatVisitorForEnum(JsonFormatVisitorWrapper visitor, JavaType typeHint, Class<?> enumType) throws JsonMappingException { // Copied from EnumSerializer#acceptJsonFormatVisitor JsonStringFormatVisitor stringVisitor = visitor.expectStringFormat(typeHint); if (stringVisitor != null) { Set<String> enums = new LinkedHashSet<String>(); for (Object en : enumType.getEnumConstants()) { try { // 21-Apr-2016, tatu: This is convoluted to the max, but essentially we // call `@JsonValue`-annotated accessor method on all Enum members, // so it all "works out". To some degree. enums.add(String.valueOf(_accessor.getValue(en))); } catch (Exception e) { Throwable t = e; while (t instanceof InvocationTargetException && t.getCause() != null) { t = t.getCause(); } ClassUtil.throwIfError(t); throw JsonMappingException.wrapWithPath(t, en, _accessor.getName() + "()"); } } stringVisitor.enumTypes(enums); } return true; } protected boolean isNaturalTypeWithStdHandling(Class<?> rawType, JsonSerializer<?> ser) { // First: do we have a natural type being handled? if (rawType.isPrimitive()) { if (rawType != Integer.TYPE && rawType != Boolean.TYPE && rawType != Double.TYPE) { return false; } } else { if (rawType != String.class && rawType != Integer.class && rawType != Boolean.class && rawType != Double.class) { return false; } } return isDefaultSerializer(ser); } /* /********************************************************** /* Other methods /********************************************************** */ @Override public String toString() { return "(@JsonValue serializer for method " + _accessor.getDeclaringClass() + "#" + _accessor.getName() + ")"; } /* /********************************************************** /* Helper class /********************************************************** */
Silly little wrapper class we need to re-route type serialization so that we can override Object to use for type id (logical type) even when asking serialization of something else (delegate type)
/** * Silly little wrapper class we need to re-route type serialization so that we can * override Object to use for type id (logical type) even when asking serialization * of something else (delegate type) */
static class TypeSerializerRerouter extends TypeSerializer { protected final TypeSerializer _typeSerializer; protected final Object _forObject; public TypeSerializerRerouter(TypeSerializer ts, Object ob) { _typeSerializer = ts; _forObject = ob; } @Override public TypeSerializer forProperty(BeanProperty prop) { // should never get called throw new UnsupportedOperationException(); } @Override public As getTypeInclusion() { return _typeSerializer.getTypeInclusion(); } @Override public String getPropertyName() { return _typeSerializer.getPropertyName(); } @Override public TypeIdResolver getTypeIdResolver() { return _typeSerializer.getTypeIdResolver(); } // // // New Write API, 2.9+ @Override // since 2.9 public WritableTypeId writeTypePrefix(JsonGenerator g, WritableTypeId typeId) throws IOException { // 28-Jun-2017, tatu: Important! Need to "override" value typeId.forValue = _forObject; return _typeSerializer.writeTypePrefix(g, typeId); } @Override // since 2.9 public WritableTypeId writeTypeSuffix(JsonGenerator g, WritableTypeId typeId) throws IOException { // NOTE: already overwrote value object so: return _typeSerializer.writeTypeSuffix(g, typeId); } // // // Old Write API, pre-2.9 @Override @Deprecated public void writeTypePrefixForScalar(Object value, JsonGenerator gen) throws IOException { _typeSerializer.writeTypePrefixForScalar(_forObject, gen); } @Override @Deprecated public void writeTypePrefixForObject(Object value, JsonGenerator gen) throws IOException { _typeSerializer.writeTypePrefixForObject(_forObject, gen); } @Override @Deprecated public void writeTypePrefixForArray(Object value, JsonGenerator gen) throws IOException { _typeSerializer.writeTypePrefixForArray(_forObject, gen); } @Override @Deprecated public void writeTypeSuffixForScalar(Object value, JsonGenerator gen) throws IOException { _typeSerializer.writeTypeSuffixForScalar(_forObject, gen); } @Override @Deprecated public void writeTypeSuffixForObject(Object value, JsonGenerator gen) throws IOException { _typeSerializer.writeTypeSuffixForObject(_forObject, gen); } @Override @Deprecated public void writeTypeSuffixForArray(Object value, JsonGenerator gen) throws IOException { _typeSerializer.writeTypeSuffixForArray(_forObject, gen); } @Override @Deprecated public void writeTypePrefixForScalar(Object value, JsonGenerator gen, Class<?> type) throws IOException { _typeSerializer.writeTypePrefixForScalar(_forObject, gen, type); } @Override @Deprecated public void writeTypePrefixForObject(Object value, JsonGenerator gen, Class<?> type) throws IOException { _typeSerializer.writeTypePrefixForObject(_forObject, gen, type); } @Override @Deprecated public void writeTypePrefixForArray(Object value, JsonGenerator gen, Class<?> type) throws IOException { _typeSerializer.writeTypePrefixForArray(_forObject, gen, type); } /* /********************************************************** /* Deprecated methods (since 2.9) /********************************************************** */ @Override @Deprecated public void writeCustomTypePrefixForScalar(Object value, JsonGenerator gen, String typeId) throws IOException { _typeSerializer.writeCustomTypePrefixForScalar(_forObject, gen, typeId); } @Override @Deprecated public void writeCustomTypePrefixForObject(Object value, JsonGenerator gen, String typeId) throws IOException { _typeSerializer.writeCustomTypePrefixForObject(_forObject, gen, typeId); } @Override @Deprecated public void writeCustomTypePrefixForArray(Object value, JsonGenerator gen, String typeId) throws IOException { _typeSerializer.writeCustomTypePrefixForArray(_forObject, gen, typeId); } @Override @Deprecated public void writeCustomTypeSuffixForScalar(Object value, JsonGenerator gen, String typeId) throws IOException { _typeSerializer.writeCustomTypeSuffixForScalar(_forObject, gen, typeId); } @Override @Deprecated public void writeCustomTypeSuffixForObject(Object value, JsonGenerator gen, String typeId) throws IOException { _typeSerializer.writeCustomTypeSuffixForObject(_forObject, gen, typeId); } @Override @Deprecated public void writeCustomTypeSuffixForArray(Object value, JsonGenerator gen, String typeId) throws IOException { _typeSerializer.writeCustomTypeSuffixForArray(_forObject, gen, typeId); } } }