Add JsonFactoryBuilder.configureForJackson2(), JsonFactoryBuilder builderWithJackson2Defaults() (#1411)

Author: pjfanning

release-notes/VERSION

@@ -53,6 +53,9 @@ JSON library.
 #1385: Create `jackson-core-[VERSION]-tests.jar` to contain shared
   test utility classes
 #1401: Rename `TreeNode.isContainerNode()` as `isContainer()` (3.0)
+#1411: Add `JsonFactoryBuilder.configureForJackson2()`,
+  `JsonFactoryBuilder builderWithJackson2Defaults()`
+ (fixed by @pjfanning)
 - Rename `JsonGenerator.Feature.AUTO_CLOSE_JSON_CONTENT` as `AUTO_CLOSE_CONTENT`
 - Add `TreeCodec.nullNode()`, `TreeNode.isNull()` methods
 - Change the way `JsonLocation.NA` is included in exception messages

src/main/java/tools/jackson/core/TSFBuilder.java

@@ -192,6 +192,19 @@ public B configure(StreamWriteFeature f, boolean state) {
         return state ? enable(f) : disable(f);
     }
 
+    /**
+     * The builder returned uses default settings more closely
+     * matching the default configs used in Jackson 2.x versions.
+     * <p>
+     *     This method is still a work in progress and may not yet fully replicate the
+     *     default settings of Jackson 2.x.
+     * </p>
+     */
+    public B configureForJackson2() {
+        return disable(StreamReadFeature.USE_FAST_DOUBLE_PARSER)
+                .disable(StreamReadFeature.USE_FAST_BIG_NUMBER_PARSER);
+    }
+
     // // // Other configuration, constraints
 
     /**

src/main/java/tools/jackson/core/json/JsonFactory.java

@@ -191,6 +191,21 @@ public static JsonFactoryBuilder builder() {
         return new JsonFactoryBuilder();
     }
 
+    /**
+     * Factory method to use for constructing {@link JsonFactory} instances with
+     * different configuration. The builder returned uses default settings more closely
+     * matching the default configs used in Jackson 2.x versions.
+     * <p>
+     *     This method is still a work in progress and may not yet fully replicate the
+     *     default settings of Jackson 2.x.
+     * </p>
+     *
+     * @return Builder instance to use
+     */
+    public static JsonFactoryBuilder builderWithJackson2Defaults() {
+        return builder().configureForJackson2();
+    }
+
     /**
      * Method for constructing a new {@link JsonFactory} that has
      * the same settings as this instance, but is otherwise

src/main/java/tools/jackson/core/json/JsonFactoryBuilder.java

@@ -116,6 +116,13 @@ public JsonFactoryBuilder configure(JsonWriteFeature f, boolean state) {
         return state ? enable(f) : disable(f);
     }
 
+    @Override
+    public JsonFactoryBuilder configureForJackson2() {
+        return super.configureForJackson2()
+                .disable(JsonWriteFeature.ESCAPE_FORWARD_SLASHES)
+                .disable(JsonWriteFeature.COMBINE_UNICODE_SURROGATES_IN_UTF8);
+    }
+
     // // // Other JSON-specific configuration
 
     /**

src/test/java/tools/jackson/core/unittest/json/JsonFactoryTest.java

@@ -345,6 +345,15 @@ public void testCanonicalizationDisabled() throws Exception {
         doCanonicalizationTest(false);
     }
 
+    @Test
+    public void testBuilderWithJackson2Defaults() {
+        JsonFactory factory = JsonFactory.builderWithJackson2Defaults().build();
+        assertFalse(factory.isEnabled(StreamReadFeature.USE_FAST_DOUBLE_PARSER));
+        assertFalse(factory.isEnabled(StreamReadFeature.USE_FAST_BIG_NUMBER_PARSER));
+        assertFalse(factory.isEnabled(JsonWriteFeature.ESCAPE_FORWARD_SLASHES));
+        assertFalse(factory.isEnabled(JsonWriteFeature.COMBINE_UNICODE_SURROGATES_IN_UTF8));
+    }
+
     // Configure the JsonFactory as expected, and verify across common shapes of input
     // to cover common JsonParser implementations.
     private void doCanonicalizationTest(boolean canonicalize) throws Exception {