An improvement to schema-info handling for Enums with @JsonValue

Author: cowtowncoder

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

@@ -175,7 +175,7 @@ public void acceptJsonFormatVisitor(JsonFormatVisitorWrapper visitor, JavaType t
         JsonStringFormatVisitor stringVisitor = visitor.expectStringFormat(typeHint);
         if (stringVisitor != null) {
             Set<String> enums = new LinkedHashSet<String>();
-
+            
             // Use toString()?
             if ((serializers != null) && 
                     serializers.isEnabled(SerializationFeature.WRITE_ENUMS_USING_TO_STRING)) {

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

@@ -5,12 +5,15 @@
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.lang.reflect.Type;
+import java.util.LinkedHashSet;
+import java.util.Set;
 
 import com.fasterxml.jackson.core.*;
 import com.fasterxml.jackson.databind.*;
 import com.fasterxml.jackson.databind.annotation.JacksonStdImpl;
 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.TypeSerializer;
 import com.fasterxml.jackson.databind.ser.BeanSerializer;
@@ -246,19 +249,34 @@ public JsonNode getSchema(SerializerProvider provider, Type typeHint)
         }
         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,
+         *    Enums are special, and unfortunately we will need to add special
+         *    handling here (see https://github.com/FasterXML/jackson-module-jsonSchema/issues/57
+         *    for details).
+         */
+        Class<?> decl = (typeHint == null) ? null : typeHint.getRawClass();
+        if (decl == null) {
+            decl = _accessorMethod.getDeclaringClass();
+        }
+        if ((decl != null) && (decl.isEnum())) {
+            if (_acceptJsonFormatVisitorForEnum(visitor, typeHint, decl)) {
+                return;
+            }
+        }
+        
         JsonSerializer<Object> ser = _valueSerializer;
         if (ser == null) {
             if (typeHint == null) {
                 if (_property != null) {
                     typeHint = _property.getType();
                 }
                 if (typeHint == null) {
-                    typeHint = visitor.getProvider().constructType(_accessorMethod.getReturnType());
+                    typeHint = visitor.getProvider().constructType(_handledType);
                 }
             }
             ser = visitor.getProvider().findTypedValueSerializer(typeHint, false, _property);
@@ -270,6 +288,43 @@ public void acceptJsonFormatVisitor(JsonFormatVisitorWrapper visitor, JavaType t
         ser.acceptJsonFormatVisitor(visitor, null); 
     }
 
+    /**
+     * 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 {
+                    enums.add(String.valueOf(_accessorMethod.invoke(en)));
+                } catch (Exception e) {
+                    Throwable t = e;
+                    while (t instanceof InvocationTargetException && t.getCause() != null) {
+                        t = t.getCause();
+                    }
+                    if (t instanceof Error) {
+                        throw (Error) t;
+                    }
+                    throw JsonMappingException.wrapWithPath(t, en, _accessorMethod.getName() + "()");
+                }
+            }
+            stringVisitor.enumTypes(enums);
+        }
+        return true;
+        
+    }
+    
     protected boolean isNaturalTypeWithStdHandling(Class<?> rawType, JsonSerializer<?> ser)
     {
         // First: do we have a natural type being handled?

src/test/java/com/fasterxml/jackson/databind/jsonschema/NewSchemaTest.java

@@ -2,6 +2,7 @@
 
 import java.util.*;
 
+import com.fasterxml.jackson.annotation.JsonValue;
 import com.fasterxml.jackson.databind.*;
 import com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatVisitorWrapper;
 import com.fasterxml.jackson.databind.jsonFormatVisitors.JsonStringFormatVisitor;
@@ -22,6 +23,15 @@ public String toString() {
         }
     }
 
+    enum TestEnumWithJsonValue {
+        A, B, C;
+        
+        @JsonValue
+        public String forSerialize() {
+            return "value-"+name();
+        }
+    }
+    
     private final ObjectMapper MAPPER = new ObjectMapper();
 
     public void testSimpleEnum() throws Exception
@@ -33,6 +43,7 @@ public void testSimpleEnum() throws Exception
             @Override
             public JsonStringFormatVisitor expectStringFormat(JavaType type) {
                 return new JsonStringFormatVisitor() {
+                    @Override
                     public void enumTypes(Set<String> enums) {
                         values.addAll(enums);
                     }
@@ -51,4 +62,31 @@ public void format(JsonValueFormat format) { }
                         ));
         assertEquals(exp, values);
     }
+
+    public void testEnumWithJsonValue() throws Exception
+    {
+        final Set<String> values = new TreeSet<String>();
+        MAPPER.acceptJsonFormatVisitor(TestEnumWithJsonValue.class, new JsonFormatVisitorWrapper.Base() {
+            @Override
+            public JsonStringFormatVisitor expectStringFormat(JavaType type) {
+                return new JsonStringFormatVisitor() {
+                    @Override
+                    public void enumTypes(Set<String> enums) {
+                        values.addAll(enums);
+                    }
+
+                    @Override
+                    public void format(JsonValueFormat format) { }
+                };
+            }
+        });
+
+        assertEquals(3, values.size());
+        TreeSet<String> exp = new TreeSet<String>(Arrays.asList(
+                        "value-A",
+                        "value-B",
+                        "value-C"
+                        ));
+        assertEquals(exp, values);
+    }
 }