Issue 2761 (#2762)

Implement #2761 (support multiple type names for `@JsonSubtypes.Type`)

Author: swayamraina

src/main/java/com/fasterxml/jackson/databind/introspect/JacksonAnnotationIntrospector.java

@@ -610,6 +610,9 @@ public List<NamedType> findSubtypes(MapperConfig<?> config, Annotated a)
         ArrayList<NamedType> result = new ArrayList<NamedType>(types.length);
         for (JsonSubTypes.Type type : types) {
             result.add(new NamedType(type.value(), type.name()));
+            for (String name : type.names()) {
+                result.add(new NamedType(type.value(), name));
+            }
         }
         return result;
     }

src/test/java/com/fasterxml/jackson/databind/jsontype/TestMultipleTypeNames.java

@@ -0,0 +1,146 @@
+package com.fasterxml.jackson.databind.jsontype;
+
+import com.fasterxml.jackson.annotation.JsonSubTypes;
+import com.fasterxml.jackson.annotation.JsonTypeInfo;
+import com.fasterxml.jackson.databind.BaseMapTest;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException;
+import org.junit.Assert;
+
+import java.util.List;
+
+
+/**
+ * Tests for sub-types id user uses,
+ *      1. only names in all sub-types
+ *      2. 'names' for multi-keys while 'name' for singular keys
+ *
+ * [ annotations#171 ]
+ * As per this feature, keys holding similar java object types can be incorporated
+ * within the same annotation.
+ * See this <a href="https://github.com/FasterXML/jackson-annotations/issues/171">issue/improvement</a>
+ */
+public class TestMultipleTypeNames extends BaseMapTest {
+
+    // serializer-deserializer
+    private final ObjectMapper MAPPER = objectMapper();
+
+
+    // common classes
+    static class MultiTypeName { }
+
+    static class A extends MultiTypeName {
+        private long x;
+        public long getX() { return x; }
+    }
+
+    static class B extends MultiTypeName {
+        private float y;
+        public float getY() { return y; }
+    }
+
+
+
+
+
+    // data for test 1
+    static class WrapperForNamesTest {
+        private List<BaseForNamesTest> base;
+        public List<BaseForNamesTest> getBase() { return base; }
+    }
+
+    static class BaseForNamesTest {
+        private String type;
+        public String getType() { return type; }
+
+        @JsonTypeInfo (
+                use = JsonTypeInfo.Id.NAME,
+                include = JsonTypeInfo.As.EXTERNAL_PROPERTY,
+                property = "type"
+        )
+        @JsonSubTypes (value = {
+                @JsonSubTypes.Type(value = A.class, names = "a"),
+                @JsonSubTypes.Type(value = B.class, names = {"b","c"}),
+        })
+        private MultiTypeName data;
+        public MultiTypeName getData() { return data; }
+    }
+
+    public void testOnlyNames () throws Exception {
+        String json;
+        WrapperForNamesTest w;
+
+        // TC 1 : all KV serialisation
+        json = "{\"base\": [{\"type\":\"a\", \"data\": {\"x\": 5}}, {\"type\":\"b\", \"data\": {\"y\": 3.1}}, {\"type\":\"c\", \"data\": {\"y\": 33.8}}]}";
+        w = MAPPER.readValue(json, WrapperForNamesTest.class);
+        Assert.assertNotNull(w);
+        Assert.assertEquals(3, w.base.size());
+        Assert.assertTrue(w.base.get(0).data instanceof A);
+        Assert.assertEquals(5l, ((A) w.base.get(0).data).x);
+        Assert.assertTrue(w.base.get(1).data instanceof B);
+        Assert.assertEquals(3.1f, ((B) w.base.get(1).data).y, 0);
+        Assert.assertTrue(w.base.get(2).data instanceof B);
+        Assert.assertEquals(33.8f, ((B) w.base.get(2).data).y, 0);
+
+
+        // TC 2 : incorrect serialisation
+        json = "{\"data\": [{\"type\":\"a\", \"data\": {\"x\": 2.2}}, {\"type\":\"b\", \"data\": {\"y\": 5.3}}, {\"type\":\"c\", \"data\": {\"y\": 9.8}}]}";
+        try  {
+            MAPPER.readValue(json, WrapperForNamesTest.class);
+            Assert.fail("This serialisation should fail 'coz of x being float");
+        } catch (UnrecognizedPropertyException e) {}
+    }
+
+
+
+
+
+    // data for test 2
+    static class WrapperForNameAndNamesTest {
+        private List<BaseForNameAndNamesTest> base;
+        public List<BaseForNameAndNamesTest> getBase() { return base; }
+    }
+
+    static class BaseForNameAndNamesTest {
+        private String type;
+        public String getType() { return type; }
+
+        @JsonTypeInfo (
+                use = JsonTypeInfo.Id.NAME,
+                include = JsonTypeInfo.As.EXTERNAL_PROPERTY,
+                property = "type"
+        )
+        @JsonSubTypes (value = {
+                @JsonSubTypes.Type(value = A.class, name = "a"),
+                @JsonSubTypes.Type(value = B.class, names = {"b","c"}),
+        })
+        private MultiTypeName data;
+        public MultiTypeName getData() { return data; }
+    }
+
+    public void testNameAndNames () throws Exception {
+        String json;
+        WrapperForNameAndNamesTest w;
+
+        // TC 1 : all KV serialisation
+        json = "{\"base\": [{\"type\":\"a\", \"data\": {\"x\": 5}}, {\"type\":\"b\", \"data\": {\"y\": 3.1}}, {\"type\":\"c\", \"data\": {\"y\": 33.8}}]}";
+        w = MAPPER.readValue(json, WrapperForNameAndNamesTest.class);
+        Assert.assertNotNull(w);
+        Assert.assertEquals(3, w.base.size());
+        Assert.assertTrue(w.base.get(0).data instanceof A);
+        Assert.assertEquals(5l, ((A) w.base.get(0).data).x);
+        Assert.assertTrue(w.base.get(1).data instanceof B);
+        Assert.assertEquals(3.1f, ((B) w.base.get(1).data).y, 0);
+        Assert.assertTrue(w.base.get(2).data instanceof B);
+        Assert.assertEquals(33.8f, ((B) w.base.get(2).data).y, 0);
+
+
+        // TC 2 : incorrect serialisation
+        json = "{\"data\": [{\"type\":\"a\", \"data\": {\"x\": 2.2}}, {\"type\":\"b\", \"data\": {\"y\": 5.3}}, {\"type\":\"c\", \"data\": {\"y\": 9.8}}]}";
+        try  {
+            MAPPER.readValue(json, WrapperForNameAndNamesTest.class);
+            Assert.fail("This serialisation should fail 'coz of x being float");
+        } catch (UnrecognizedPropertyException e) {}
+    }
+
+}