com.fasterxml.jackson.databind.ser.std.EnumSerializer Maven / Gradle / Ivy
Show all versions of jackson-databind Show documentation
package com.fasterxml.jackson.databind.ser.std;
import java.io.IOException;
import java.lang.reflect.Type;
import java.util.*;
import com.fasterxml.jackson.annotation.JsonFormat;
import com.fasterxml.jackson.annotation.JsonFormat.Shape;
import com.fasterxml.jackson.core.*;
import com.fasterxml.jackson.core.io.SerializedString;
import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.annotation.JacksonStdImpl;
import com.fasterxml.jackson.databind.introspect.Annotated;
import com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatVisitorWrapper;
import com.fasterxml.jackson.databind.jsonFormatVisitors.JsonStringFormatVisitor;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.fasterxml.jackson.databind.ser.ContextualSerializer;
import com.fasterxml.jackson.databind.util.EnumValues;
/**
* Standard serializer used for {@link java.lang.Enum} types.
*
* Based on {@link StdScalarSerializer} since the JSON value is
* scalar (String).
*
* @author tatu
*/
@JacksonStdImpl
public class EnumSerializer
extends StdScalarSerializer>
implements ContextualSerializer
{
/**
* This map contains pre-resolved values (since there are ways
* to customize actual String constants to use) to use as
* serializations.
*/
protected final EnumValues _values;
/**
* Flag that is set if we statically know serialization choice
* between index and textual format (null if it needs to be dynamically
* checked).
*
* @since 2.1
*/
protected final Boolean _serializeAsIndex;
/*
/**********************************************************
/* Construction, initialization
/**********************************************************
*/
/**
* @deprecated Since 2.1
*/
@Deprecated
public EnumSerializer(EnumValues v) {
this(v, null);
}
public EnumSerializer(EnumValues v, Boolean serializeAsIndex)
{
super(Enum.class, false);
_values = v;
_serializeAsIndex = serializeAsIndex;
}
/**
* Factory method used by {@link com.fasterxml.jackson.databind.ser.BasicSerializerFactory}
* for constructing serializer instance of Enum types.
*
* @since 2.1
*/
public static EnumSerializer construct(Class> enumClass, SerializationConfig config,
BeanDescription beanDesc, JsonFormat.Value format)
{
// [JACKSON-212]: If toString() is to be used instead, leave EnumValues null
AnnotationIntrospector intr = config.getAnnotationIntrospector();
EnumValues v = config.isEnabled(SerializationFeature.WRITE_ENUMS_USING_TO_STRING)
? EnumValues.constructFromToString(enumClass, intr) : EnumValues.constructFromName(enumClass, intr);
Boolean serializeAsIndex = _isShapeWrittenUsingIndex(enumClass, format, true);
return new EnumSerializer(v, serializeAsIndex);
}
/**
* @deprecated Since 2.1 use the variant that takes in format argument.
*/
@Deprecated
public static EnumSerializer construct(Class> enumClass, SerializationConfig config,
BeanDescription beanDesc)
{
return construct(enumClass, config, beanDesc, beanDesc.findExpectedFormat(null));
}
/**
* To support some level of per-property configuration, we will need
* to make things contextual. We are limited to "textual vs index"
* choice here, however.
*/
public JsonSerializer createContextual(SerializerProvider prov,
BeanProperty property) throws JsonMappingException
{
if (property != null) {
JsonFormat.Value format = prov.getAnnotationIntrospector().findFormat((Annotated) property.getMember());
if (format != null) {
Boolean serializeAsIndex = _isShapeWrittenUsingIndex(property.getType().getRawClass(), format, false);
if (serializeAsIndex != _serializeAsIndex) {
return new EnumSerializer(_values, serializeAsIndex);
}
}
}
return this;
}
/*
/**********************************************************
/* Extended API for Jackson databind core
/**********************************************************
*/
public EnumValues getEnumValues() { return _values; }
/*
/**********************************************************
/* Actual serialization
/**********************************************************
*/
@Override
public final void serialize(Enum en, JsonGenerator jgen, SerializerProvider provider)
throws IOException, JsonGenerationException
{
// [JACKSON-684]: serialize as index?
if (_serializeAsIndex(provider)) {
jgen.writeNumber(en.ordinal());
return;
}
jgen.writeString(_values.serializedValueFor(en));
}
@Override
public JsonNode getSchema(SerializerProvider provider, Type typeHint)
{
// [JACKSON-684]: serialize as index?
if (_serializeAsIndex(provider)) {
return createSchemaNode("integer", true);
}
ObjectNode objectNode = createSchemaNode("string", true);
if (typeHint != null) {
JavaType type = provider.constructType(typeHint);
if (type.isEnumType()) {
ArrayNode enumNode = objectNode.putArray("enum");
for (SerializedString value : _values.values()) {
enumNode.add(value.getValue());
}
}
}
return objectNode;
}
@Override
public void acceptJsonFormatVisitor(JsonFormatVisitorWrapper visitor, JavaType typeHint)
{
// [JACKSON-684]: serialize as index?
if (visitor.getProvider().isEnabled(SerializationFeature.WRITE_ENUMS_USING_INDEX)) {
visitor.expectIntegerFormat(typeHint);
} else {
JsonStringFormatVisitor stringVisitor = visitor.expectStringFormat(typeHint);
if (typeHint != null && visitor != null) {
if (typeHint.isEnumType()) {
// important: ensure that order is retained
Set enums = new LinkedHashSet();
for (SerializedString value : _values.values()) {
enums.add(value.getValue());
}
stringVisitor.enumTypes(enums);
}
}
}
}
/*
/**********************************************************
/* Helper methods
/**********************************************************
*/
protected final boolean _serializeAsIndex(SerializerProvider provider)
{
if (_serializeAsIndex != null) {
return _serializeAsIndex.booleanValue();
}
return provider.isEnabled(SerializationFeature.WRITE_ENUMS_USING_INDEX);
}
/**
* Helper method called to check whether
*/
protected static Boolean _isShapeWrittenUsingIndex(Class enumClass,
JsonFormat.Value format, boolean fromClass)
{
JsonFormat.Shape shape = (format == null) ? null : format.getShape();
if (shape == null) {
return null;
}
if (shape == Shape.ANY || shape == Shape.SCALAR) { // i.e. "default", check dynamically
return null;
}
if (shape == Shape.STRING) {
return Boolean.FALSE;
}
if (shape.isNumeric()) {
return Boolean.TRUE;
}
throw new IllegalArgumentException("Unsupported serialization shape ("+shape+") for Enum "+enumClass.getName()
+", not supported as "
+ (fromClass? "class" : "property")
+" annotation");
}
}