Fix #762

Author: cowtowncoder

release-notes/VERSION

@@ -22,6 +22,7 @@ Project: jackson-databind
 #737: Add support for writing raw values in TokenBuffer
  (suggested by Guillaume S, gsmet@github)
 #743: Add `RawValue` helper type, for piping raw values through `TokenBuffer`
+#762: Add `ObjectWriter.withoutRootName()`, `ObjectReader.withoutRootName()`
 #765: `SimpleType.withStaticTyping()` impl incorrect
 - Remove old cglib compatibility tests; cause problems in Eclipse
 

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

@@ -537,6 +537,20 @@ public ObjectReader withRootName(String rootName) {
         return _with(_config.withRootName(rootName));
     }
 
+    /**
+     * Convenience method that is same as calling:
+     *<code>
+     *   withRootName("")
+     *</code>
+     * which will forcibly prevent use of root name wrapping when writing
+     * values with this {@link ObjectReader}.
+     * 
+     * @since 2.6
+     */
+    public ObjectReader withoutRootName() {
+        return _with(_config.withRootName(""));
+    }
+    
     /**
      * Method for constructing a new instance with configuration that
      * passes specified {@link FormatSchema} to {@link JsonParser} that

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

@@ -402,12 +402,30 @@ public ObjectWriter with(PrettyPrinter pp) {
      *<p>
      * Note that method does NOT change state of this reader, but
      * rather construct and returns a newly configured instance.
+     * 
+     * @param rootName Root name to use, if non-empty; `null` for "use defaults",
+     *    and empty String ("") for "do NOT add root wrapper"
      */
     public ObjectWriter withRootName(String rootName) {
         SerializationConfig newConfig = _config.withRootName(rootName);
         return (newConfig == _config) ? this :  _new(this, newConfig);
     }
 
+    /**
+     * Convenience method that is same as calling:
+     *<code>
+     *   withRootName("")
+     *</code>
+     * which will forcibly prevent use of root name wrapping when writing
+     * values with this {@link ObjectWriter}.
+     * 
+     * @since 2.6
+     */
+    public ObjectWriter withoutRootName() {
+        SerializationConfig newConfig = _config.withRootName("");
+        return (newConfig == _config) ? this :  _new(this, newConfig);
+    }
+    
     /**
      * Method that will construct a new instance that uses specific format schema
      * for serialization.

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

@@ -98,8 +98,22 @@ public void testRootUsingExplicitConfig() throws Exception
         json = wrapping.writer().withRootName("").writeValueAsString(new Bean());
         assertEquals("{\"a\":3}", json);
 
+        // 21-Apr-2015, tatu: Alternative available with 2.6 as well:
+        json = wrapping.writer().withoutRootName().writeValueAsString(new Bean());
+        assertEquals("{\"a\":3}", json);
+
         bean = wrapping.reader(Bean.class).withRootName("").readValue(json);
         assertNotNull(bean);
+        assertEquals(3, bean.a);
+
+        bean = wrapping.reader(Bean.class).withoutRootName().readValue("{\"a\":4}");
+        assertNotNull(bean);
+        assertEquals(4, bean.a);
+
+        // and back to defaults
+        bean = wrapping.reader(Bean.class).readValue("{\"rudy\":{\"a\":7}}");
+        assertNotNull(bean);
+        assertEquals(7, bean.a);
     }
 
     /*