Merge pull request #855 from MahiFX/V4Fix

Follow ups from #838

Author: cowtowncoder

src/main/java/com/fasterxml/jackson/databind/SerializerProvider.java

@@ -1,21 +1,32 @@
 package com.fasterxml.jackson.databind;
 
-import java.io.IOException;
-import java.text.DateFormat;
-import java.util.*;
-
 import com.fasterxml.jackson.annotation.ObjectIdGenerator;
-import com.fasterxml.jackson.core.*;
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.cfg.ContextAttributes;
 import com.fasterxml.jackson.databind.deser.ContextualDeserializer;
 import com.fasterxml.jackson.databind.introspect.Annotated;
 import com.fasterxml.jackson.databind.jsontype.TypeSerializer;
-import com.fasterxml.jackson.databind.ser.*;
-import com.fasterxml.jackson.databind.ser.impl.*;
+import com.fasterxml.jackson.databind.ser.ContextualSerializer;
+import com.fasterxml.jackson.databind.ser.FilterProvider;
+import com.fasterxml.jackson.databind.ser.ResolvableSerializer;
+import com.fasterxml.jackson.databind.ser.SerializerCache;
+import com.fasterxml.jackson.databind.ser.SerializerFactory;
+import com.fasterxml.jackson.databind.ser.impl.FailingSerializer;
+import com.fasterxml.jackson.databind.ser.impl.ReadOnlyClassToSerializerMap;
+import com.fasterxml.jackson.databind.ser.impl.TypeWrappedSerializer;
+import com.fasterxml.jackson.databind.ser.impl.UnknownSerializer;
+import com.fasterxml.jackson.databind.ser.impl.WritableObjectId;
 import com.fasterxml.jackson.databind.ser.std.NullSerializer;
 import com.fasterxml.jackson.databind.type.TypeFactory;
 import com.fasterxml.jackson.databind.util.ClassUtil;
 
+import java.io.IOException;
+import java.text.DateFormat;
+import java.util.Date;
+import java.util.Locale;
+import java.util.TimeZone;
+
 /**
  * Class that defines API used by {@link ObjectMapper} and
  * {@link JsonSerializer}s to obtain serializers capable of serializing
@@ -722,6 +733,14 @@ public JsonSerializer<Object> findTypedValueSerializer(JavaType valueType, boole
         return ser;
     }
 
+    /**
+     * Method called to get a Typeserialize to use for accessing Type Information for a given Java class
+     * Useful for schema generators.
+     */
+    public TypeSerializer findTypeSerializer(JavaType javaType) throws JsonMappingException {
+        return _serializerFactory.createTypeSerializer(_config, javaType);
+    }
+
     /**
      * Method called to get the serializer to use for serializing
      * non-null Map keys. Separation from regular

src/main/java/com/fasterxml/jackson/databind/jsontype/impl/TypeNameIdResolver.java

@@ -1,14 +1,16 @@
 package com.fasterxml.jackson.databind.jsontype.impl;
 
-import java.util.*;
-
 import com.fasterxml.jackson.annotation.JsonTypeInfo;
 import com.fasterxml.jackson.databind.BeanDescription;
 import com.fasterxml.jackson.databind.DatabindContext;
 import com.fasterxml.jackson.databind.JavaType;
 import com.fasterxml.jackson.databind.cfg.MapperConfig;
 import com.fasterxml.jackson.databind.jsontype.NamedType;
 
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.TreeSet;
+
 public class TypeNameIdResolver extends TypeIdResolverBase
 {
     protected final MapperConfig<?> _config;
@@ -80,7 +82,15 @@ public static TypeNameIdResolver construct(MapperConfig<?> config, JavaType base
     @Override
     public String idFromValue(Object value)
     {
-        Class<?> cls = _typeFactory.constructType(value.getClass()).getRawClass();
+        return idFromClass(value.getClass());
+    }
+
+    protected String idFromClass(Class<?> clazz)
+    {
+        if(clazz==null){
+            return null;
+        }
+        Class<?> cls = _typeFactory.constructType(clazz).getRawClass();
         final String key = cls.getName();
         String name;
         synchronized (_typeToId) {
@@ -108,7 +118,7 @@ public String idFromValueAndType(Object value, Class<?> type) {
          *   it seems; nothing much we can figure out that way.
          */
         if (value == null) {
-            return null;
+            return idFromClass(type);
         }
         return idFromValue(value);
     }