Fix #955. Added DeserializationFeature USE BASE TYPE AS DEFAULT (#2036)

FasterXML · May 17, 2018 · 69416ee · 69416ee
1 parent 324b2d7
commit 69416ee
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diff --git a/src/main/java/com/fasterxml/jackson/databind/DeserializationFeature.java b/src/main/java/com/fasterxml/jackson/databind/DeserializationFeature.java
@@ -459,6 +459,14 @@ public enum DeserializationFeature implements ConfigFeature
      */
     ADJUST_DATES_TO_CONTEXT_TIME_ZONE(true),
 
+    /**
+     * Feature that specifies whether the given concrete class is used
+     * if type property is missing.
+     *
+     * @since 2.9
+     */
+    USE_BASE_TYPE_AS_DEFAULT(false),
+
     /*
     /******************************************************
     /* Other

diff --git a/src/main/java/com/fasterxml/jackson/databind/jsontype/impl/StdTypeResolverBuilder.java b/src/main/java/com/fasterxml/jackson/databind/jsontype/impl/StdTypeResolverBuilder.java
@@ -120,10 +120,36 @@ public TypeDeserializer buildTypeDeserializer(DeserializationConfig config,
 
         TypeIdResolver idRes = idResolver(config, baseType, subtypes, false, true);
 
-        JavaType defaultImpl;
+        JavaType defaultImpl = defineDefaultImpl(config, baseType);
 
+        // First, method for converting type info to type id:
+        switch (_includeAs) {
+        case WRAPPER_ARRAY:
+            return new AsArrayTypeDeserializer(baseType, idRes,
+                    _typeProperty, _typeIdVisible, defaultImpl);
+        case PROPERTY:
+        case EXISTING_PROPERTY: // as per [#528] same class as PROPERTY
+            return new AsPropertyTypeDeserializer(baseType, idRes,
+                    _typeProperty, _typeIdVisible, defaultImpl, _includeAs);
+        case WRAPPER_OBJECT:
+            return new AsWrapperTypeDeserializer(baseType, idRes,
+                    _typeProperty, _typeIdVisible, defaultImpl);
+        case EXTERNAL_PROPERTY:
+            return new AsExternalTypeDeserializer(baseType, idRes,
+                    _typeProperty, _typeIdVisible, defaultImpl);
+        }
+        throw new IllegalStateException("Do not know how to construct standard type serializer for inclusion type: "+_includeAs);
+    }
+
+    protected JavaType defineDefaultImpl(DeserializationConfig config, JavaType baseType) {
+        JavaType defaultImpl;
         if (_defaultImpl == null) {
-            defaultImpl = null;
+            //Fis of issue #955
+            if (config.isEnabled(DeserializationFeature.USE_BASE_TYPE_AS_DEFAULT) && !baseType.isAbstract()) {
+                defaultImpl = baseType;
+            } else {
+                defaultImpl = null;
+            }
         } else {
             // 20-Mar-2016, tatu: It is important to do specialization go through
             //   TypeFactory to ensure proper resolution; with 2.7 and before, direct
@@ -132,7 +158,7 @@ public TypeDeserializer buildTypeDeserializer(DeserializationConfig config,
             //   if so, need to add explicit checks for marker types. Not ideal, but
             //   seems like a reasonable compromise.
             if ((_defaultImpl == Void.class)
-                     || (_defaultImpl == NoClass.class)) {
+                    || (_defaultImpl == NoClass.class)) {
                 defaultImpl = config.getTypeFactory().constructType(_defaultImpl);
             } else {
                 if (baseType.hasRawClass(_defaultImpl)) { // common enough to check
@@ -156,24 +182,7 @@ public TypeDeserializer buildTypeDeserializer(DeserializationConfig config,
                 }
             }
         }
-
-        // First, method for converting type info to type id:
-        switch (_includeAs) {
-        case WRAPPER_ARRAY:
-            return new AsArrayTypeDeserializer(baseType, idRes,
-                    _typeProperty, _typeIdVisible, defaultImpl);
-        case PROPERTY:
-        case EXISTING_PROPERTY: // as per [#528] same class as PROPERTY
-            return new AsPropertyTypeDeserializer(baseType, idRes,
-                    _typeProperty, _typeIdVisible, defaultImpl, _includeAs);
-        case WRAPPER_OBJECT:
-            return new AsWrapperTypeDeserializer(baseType, idRes,
-                    _typeProperty, _typeIdVisible, defaultImpl);
-        case EXTERNAL_PROPERTY:
-            return new AsExternalTypeDeserializer(baseType, idRes,
-                    _typeProperty, _typeIdVisible, defaultImpl);
-        }
-        throw new IllegalStateException("Do not know how to construct standard type serializer for inclusion type: "+_includeAs);
+        return defaultImpl;
     }
 
     /*

diff --git a/src/test/java/com/fasterxml/jackson/databind/jsontype/TestBaseTypeAsDefault.java b/src/test/java/com/fasterxml/jackson/databind/jsontype/TestBaseTypeAsDefault.java
@@ -0,0 +1,93 @@
+package com.fasterxml.jackson.databind.jsontype;
+
+import com.fasterxml.jackson.annotation.JsonTypeInfo;
+import com.fasterxml.jackson.databind.BaseMapTest;
+import com.fasterxml.jackson.databind.DeserializationFeature;
+import com.fasterxml.jackson.databind.JsonMappingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import java.io.IOException;
+
+public class TestBaseTypeAsDefault extends BaseMapTest {
+
+    private ObjectMapper objectMapper;
+
+    @Override
+    public void setUp() {
+        objectMapper = new ObjectMapper();
+        objectMapper.enable(DeserializationFeature.USE_BASE_TYPE_AS_DEFAULT);
+    }
+
+    public void testPositiveForParent() throws IOException {
+        Object o = objectMapper.readerFor(Parent.class).readValue("{}");
+
+        assertEquals(o.getClass(), Parent.class);
+    }
+
+    public void testPositiveForChild() throws IOException {
+        Object o = objectMapper.readerFor(Child.class).readValue("{}");
+
+        assertEquals(o.getClass(), Child.class);
+    }
+
+    public void testNegativeForParent() throws IOException {
+        objectMapper.disable(DeserializationFeature.USE_BASE_TYPE_AS_DEFAULT);
+
+        try {
+            Object o = objectMapper.readerFor(Parent.class).readValue("{}");
+        } catch (JsonMappingException ex) {
+            assertTrue(ex.getMessage().contains("missing type id property '@class'"));
+        }
+    }
+
+    public void testNegativeForChild() throws IOException {
+        objectMapper.disable(DeserializationFeature.USE_BASE_TYPE_AS_DEFAULT);
+
+        try {
+            Object o = objectMapper.readerFor(Child.class).readValue("{}");
+        } catch (JsonMappingException ex) {
+            assertTrue(ex.getMessage().contains("missing type id property '@class'"));
+        }
+    }
+
+    public void testNegativeConversionForAbstract() throws IOException {
+        try {
+            Object o = objectMapper.readerFor(AbstractParentWithDefault.class).readValue("{}");
+        } catch (JsonMappingException ex) {
+            assertTrue(ex.getMessage().contains("missing property '@class'"));
+        }
+    }
+
+    public void testPositiveWithTypeSpecification() throws IOException {
+        Object o = objectMapper.readerFor(Parent.class)
+                .readValue("{\"@class\":\"com.fasterxml.jackson.databind.jsontype.TestBaseTypeAsDefault$Child\"}");
+
+        assertEquals(o.getClass(), Child.class);
+    }
+
+    public void testPositiveWithManualDefault() throws IOException {
+        Object o = objectMapper.readerFor(ChildOfAbstract.class).readValue("{}");
+
+        assertEquals(o.getClass(), ChildOfChild.class);
+    }
+
+    @JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, property = "@class")
+    static class Parent {
+    }
+
+
+    static class Child extends Parent {
+    }
+
+
+    @JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, property = "@class", defaultImpl = ChildOfChild.class)
+    static abstract class AbstractParentWithDefault {
+    }
+
+
+    static class ChildOfAbstract extends AbstractParentWithDefault {
+    }
+
+    static class ChildOfChild extends ChildOfAbstract {
+    }
+}