Fix #2153

Author: cowtowncoder

release-notes/VERSION-2.x

@@ -14,6 +14,7 @@ Project: jackson-databind
 #2116: Make NumberSerializers.Base public and its inherited classes not final
  (requested by Édouard M)
 #2126: `DeserializationContext.instantiationException()` throws `InvalidDefinitionException`
+#2153: Add `JsonMapper` to replace generic `ObjectMapper` usage
 
 2.9.7 (not yet released)
 

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

@@ -128,19 +128,6 @@ public class ObjectMapper
     /**********************************************************
      */
 
-    /**
-     * Base implementation for "Vanilla" {@link ObjectMapper}, used with JSON backend
-     * as well as for some of simpler formats that do not require mapper level overrides.
-     *
-     * @since 2.10
-     */
-    public static class Builder extends MapperBuilder<ObjectMapper, Builder>
-    {
-        public Builder(JsonFactory tsf) {
-            super(new ObjectMapper(tsf));
-        }
-    }
-    
     /**
      * Enumeration used with {@link ObjectMapper#enableDefaultTyping()}
      * to specify what kind of types (classes) default typing should
@@ -604,39 +591,6 @@ protected ClassIntrospector defaultClassIntrospector() {
         return new BasicClassIntrospector();
     }
 
-    /*
-    /**********************************************************
-    /* Builder-based construction (2.10)
-    /**********************************************************
-     */
-
-    // 16-Feb-2018, tatu: Arggghh. Due to Java Type Erasure rules, override, even static methods
-    //    are apparently bound to compatibility rules (despite them not being real overrides at all).
-    //    And because there is no "JsonMapper" we need to use odd weird typing here. Instead of simply
-    //    using `MapperBuilder` we already go
-
-    /**
-     * Short-cut for:
-     *<pre>
-     *   return builder(JsonFactory.builder().build());
-     *</pre>
-     *
-     * @since 2.10
-     */
-    @SuppressWarnings("unchecked")
-    public static <M extends ObjectMapper, B extends MapperBuilder<M,B>> MapperBuilder<M,B> builder() {
-        return (MapperBuilder<M,B>) jsonBuilder();
-    }
-
-    // But here we can just use simple typing. Since there are no overloads of any kind.
-    public static ObjectMapper.Builder jsonBuilder() {
-        return new ObjectMapper.Builder(new JsonFactory());
-    }
-
-    public static ObjectMapper.Builder builder(JsonFactory streamFactory) {
-        return new ObjectMapper.Builder(streamFactory);
-    }
-
     /*
     /**********************************************************
     /* Methods sub-classes MUST override

src/main/java/com/fasterxml/jackson/databind/json/JsonMapper.java

@@ -0,0 +1,84 @@
+package com.fasterxml.jackson.databind.json;
+
+import com.fasterxml.jackson.core.JsonFactory;
+import com.fasterxml.jackson.core.Version;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.cfg.MapperBuilder;
+import com.fasterxml.jackson.databind.cfg.PackageVersion;
+
+/**
+ *
+ * @since 2.10
+ */
+public class JsonMapper extends ObjectMapper
+{
+    private static final long serialVersionUID = 1L;
+
+    /**
+     * Base implementation for "Vanilla" {@link ObjectMapper}, used with
+     * JSON dataformat backend.
+     *
+     * @since 2.10
+     */
+    public static class Builder extends MapperBuilder<JsonMapper, Builder>
+    {
+        public Builder(JsonMapper m) {
+            super(m);
+        }
+    }
+
+    /*
+    /**********************************************************
+    /* Life-cycle, constructors
+    /**********************************************************
+     */
+
+    public JsonMapper() {
+        this(new JsonFactory());
+    }
+
+    public JsonMapper(JsonFactory f) {
+        super(f);
+    }
+
+    protected JsonMapper(JsonMapper src) {
+        super(src);
+    }
+
+    @Override
+    public JsonMapper copy()
+    {
+        _checkInvalidCopy(JsonMapper.class);
+        return new JsonMapper(this);
+    }
+
+    /*
+    /**********************************************************
+    /* Life-cycle, builders
+    /**********************************************************
+     */
+
+    public static JsonMapper.Builder builder() {
+        return new Builder(new JsonMapper());
+    }
+
+    public static Builder builder(JsonFactory streamFactory) {
+        return new Builder(new JsonMapper(streamFactory));
+    }
+
+    /*
+    /**********************************************************
+    /* Standard method overrides
+    /**********************************************************
+     */
+
+    @Override
+    public Version version() {
+        return PackageVersion.VERSION;
+    }
+
+    @Override
+    public JsonFactory getFactory() {
+        return _jsonFactory;
+    }
+}

src/test/java/com/fasterxml/jackson/databind/BaseMapTest.java

@@ -11,6 +11,7 @@
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.deser.std.StdScalarDeserializer;
+import com.fasterxml.jackson.databind.json.JsonMapper;
 import com.fasterxml.jackson.databind.ser.std.StdScalarSerializer;
 import com.fasterxml.jackson.databind.type.TypeFactory;
 
@@ -232,15 +233,15 @@ protected static ObjectMapper newObjectMapper() {
         return new ObjectMapper();
     }
 
-    // @since 2.10
-    protected static ObjectMapper.Builder objectMapperBuilder() {
+    // @since 2.10s
+    protected static JsonMapper.Builder objectMapperBuilder() {
         /* 27-Aug-2018, tatu: Now this is weird -- with Java 7, we seem to need
          *   explicit type parameters, but not with Java 8.
          *   This need renders builder-approach pretty much useless for Java 7,
          *   which is ok for 3.x (where baseline is Java 8), but potentially
          *   problematic for 2.10. Oh well.
          */
-        return (ObjectMapper.Builder) ObjectMapper.<ObjectMapper,ObjectMapper.Builder>builder();
+        return JsonMapper.builder();
     }
 
     // @since 2.7