Use JsonProperty and lowercase feature with Enum serialization despite write using toString (#4039)

Author: iProdigy

src/main/java/com/fasterxml/jackson/databind/ser/std/EnumSerializer.java

@@ -59,6 +59,15 @@ public class EnumSerializer
      */
     protected final EnumValues _valuesByEnumNaming;
 
+    /**
+     * Map that contains pre-resolved values for {@link Enum#toString} to use for serialization,
+     * while respecting {@link com.fasterxml.jackson.annotation.JsonProperty}
+     * and {@link com.fasterxml.jackson.databind.cfg.EnumFeature#WRITE_ENUMS_TO_LOWERCASE}.
+     *
+     * @since 2.16
+     */
+    protected final EnumValues _valuesByToString;
+
     /*
     /**********************************************************
     /* Construction, initialization
@@ -71,6 +80,7 @@ public EnumSerializer(EnumValues v, Boolean serializeAsIndex)
         _values = v;
         _serializeAsIndex = serializeAsIndex;
         _valuesByEnumNaming = null;
+        _valuesByToString = null;
     }
 
     /**
@@ -82,6 +92,20 @@ public EnumSerializer(EnumValues v, Boolean serializeAsIndex, EnumValues valuesB
         _values = v;
         _serializeAsIndex = serializeAsIndex;
         _valuesByEnumNaming = valuesByEnumNaming;
+        _valuesByToString = null;
+    }
+
+    /**
+     * @since 2.16
+     */
+    public EnumSerializer(EnumValues v, Boolean serializeAsIndex, EnumValues valuesByEnumNaming,
+            EnumValues valuesByToString)
+    {
+        super(v.getEnumClass(), false);
+        _values = v;
+        _serializeAsIndex = serializeAsIndex;
+        _valuesByEnumNaming = valuesByEnumNaming;
+        _valuesByToString = valuesByToString;
     }
 
     /**
@@ -100,8 +124,9 @@ public static EnumSerializer construct(Class<?> enumClass, SerializationConfig c
          */
         EnumValues v = EnumValues.constructFromName(config, beanDesc.getClassInfo());
         EnumValues valuesByEnumNaming = constructEnumNamingStrategyValues(config, (Class<Enum<?>>) enumClass, beanDesc.getClassInfo());
+        EnumValues valuesByToString = EnumValues.constructFromToString(config, beanDesc.getClassInfo());
         Boolean serializeAsIndex = _isShapeWrittenUsingIndex(enumClass, format, true, null);
-        return new EnumSerializer(v, serializeAsIndex, valuesByEnumNaming);
+        return new EnumSerializer(v, serializeAsIndex, valuesByEnumNaming, valuesByToString);
     }
 
     /**
@@ -154,7 +179,7 @@ public final void serialize(Enum<?> en, JsonGenerator gen, SerializerProvider se
         }
         // [databind#749]: or via toString()?
         if (serializers.isEnabled(SerializationFeature.WRITE_ENUMS_USING_TO_STRING)) {
-            gen.writeString(en.toString());
+            gen.writeString(_valuesByToString.serializedValueFor(en));
             return;
         }
         gen.writeString(_values.serializedValueFor(en));
@@ -205,8 +230,8 @@ public void acceptJsonFormatVisitor(JsonFormatVisitorWrapper visitor, JavaType t
             // Use toString()?
             if ((serializers != null) &&
                     serializers.isEnabled(SerializationFeature.WRITE_ENUMS_USING_TO_STRING)) {
-                for (Enum<?> e : _values.enums()) {
-                    enums.add(e.toString());
+                for (SerializableString value : _valuesByToString.values()) {
+                    enums.add(value.getValue());
                 }
             } else {
                 // No, serialize using name() or explicit overrides

src/main/java/com/fasterxml/jackson/databind/util/EnumValues.java

@@ -39,7 +39,7 @@ private EnumValues(Class<Enum<?>> enumClass, SerializableString[] textual)
      */
     public static EnumValues construct(SerializationConfig config, AnnotatedClass annotatedClass) {
         if (config.isEnabled(SerializationFeature.WRITE_ENUMS_USING_TO_STRING)) {
-            return constructFromToString(config, _enumClass(annotatedClass.getRawType()));
+            return constructFromToString(config, annotatedClass);
         }
         return constructFromName(config, annotatedClass);
     }
@@ -104,6 +104,44 @@ public static EnumValues constructFromName(MapperConfig<?> config, AnnotatedClas
         return construct(enumCls, textual);
     }
 
+    /**
+     * @since 2.16
+     */
+    public static EnumValues constructFromToString(MapperConfig<?> config, AnnotatedClass annotatedClass)
+    {
+        // prepare data
+        final AnnotationIntrospector ai = config.getAnnotationIntrospector();
+        final boolean useLowerCase = config.isEnabled(EnumFeature.WRITE_ENUMS_TO_LOWERCASE);
+        final Class<?> enumCls0 = annotatedClass.getRawType();
+        final Class<Enum<?>> enumCls = _enumClass(enumCls0);
+        final Enum<?>[] enumConstants = _enumConstants(enumCls0);
+
+        // introspect
+        String[] names = new String[enumConstants.length];
+        if (ai != null) {
+            ai.findEnumValues(config, annotatedClass, enumConstants, names);
+        }
+
+        // build
+        SerializableString[] textual = new SerializableString[enumConstants.length];
+        for (int i = 0; i < enumConstants.length; i++) {
+            String name = names[i];
+            if (name == null) {
+                Enum<?> en = enumConstants[i];
+                name = en.toString();
+            }
+            if (useLowerCase) {
+                name = name.toLowerCase();
+            }
+            textual[i] = config.compileString(name);
+        }
+        return construct(enumCls, textual);
+    }
+
+    /**
+     * @deprecated since 2.16; use {@link #constructFromToString(MapperConfig, AnnotatedClass)} instead
+     */
+    @Deprecated
     public static EnumValues constructFromToString(MapperConfig<?> config, Class<Enum<?>> enumClass)
     {
         Class<? extends Enum<?>> cls = ClassUtil.findEnumType(enumClass);

src/test/java/com/fasterxml/jackson/databind/ser/jdk/EnumSerializationTest.java

@@ -296,6 +296,13 @@ public void testEnumsWithJsonProperty() throws Exception {
         assertEquals(q("aleph"), MAPPER.writeValueAsString(EnumWithJsonProperty.A));
     }
 
+    public void testEnumsWithJsonPropertyEnableToString() throws Exception {
+        String result = MAPPER.writerFor(EnumWithJsonProperty.class)
+                .with(SerializationFeature.WRITE_ENUMS_USING_TO_STRING)
+                .writeValueAsString(EnumWithJsonProperty.A);
+        assertEquals(q("aleph"), result);
+    }
+
     // [databind#1535]
     public void testEnumKeysWithJsonProperty() throws Exception {
         Map<EnumWithJsonProperty,Integer> input = new HashMap<EnumWithJsonProperty,Integer>();