Fix #1017 (add InvalidTypeIdException)

Author: cowtowncoder

release-notes/VERSION

@@ -15,6 +15,8 @@ Project: jackson-databind
 #990: Allow failing on `null` values for creator (add 
   `DeserializationFeature.FAIL_ON_NULL_CREATOR_PROPERTIES`)
  (contributed by mkokho@github)
+#1017: Add new mapping exception type ('InvalidTypeIdException') for subtype resolution errors
+ (suggested by natnan@github)
 #1082: Can not use static Creator factory methods for `Enum`s, with JsonCreator.Mode.PROPERTIES
  (contributed by Lokesh K)
 #1084: Change `TypeDeserializerBase` to take `JavaType` for `defaultImpl`, NOT `Class`

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

@@ -15,6 +15,7 @@
 import com.fasterxml.jackson.databind.deser.impl.ReadableObjectId;
 import com.fasterxml.jackson.databind.deser.impl.TypeWrappedDeserializer;
 import com.fasterxml.jackson.databind.exc.InvalidFormatException;
+import com.fasterxml.jackson.databind.exc.InvalidTypeIdException;
 import com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException;
 import com.fasterxml.jackson.databind.introspect.Annotated;
 import com.fasterxml.jackson.databind.jsontype.TypeDeserializer;
@@ -893,12 +894,12 @@ public JavaType handleUnknownTypeId(JavaType baseType, String id,
                 if (type.isTypeOrSubTypeOf(baseType.getRawClass())) {
                     return type;
                 }
-                throw unknownTypeException(baseType, id,
+                throw unknownTypeIdException(baseType, id,
                         "problem handler tried to resolve into non-subtype: "+type);
             }
             h = h.next();
         }
-        throw unknownTypeException(baseType, id, extraDesc);
+        throw unknownTypeIdException(baseType, id, extraDesc);
     }
 
     /*
@@ -1072,7 +1073,7 @@ public JsonMappingException mappingException(String msgTemplate, Object... args)
     /*
     /**********************************************************
     /* Methods for constructing semantic exceptions; usually not
-    /* to be called direclty, call `handleXxx()` instead
+    /* to be called directly, call `handleXxx()` instead
     /**********************************************************
      */
 
@@ -1090,17 +1091,20 @@ public JsonMappingException weirdKeyException(Class<?> keyClass, String keyValue
     }
 
     /**
-     * Helper method for constructing exception to indicate that end-of-input was
-     * reached while still expecting more tokens to deserialize value of specified type.
-     *
-     * @deprecated Since 2.8; currently no way to catch EOF at databind level
+     * Helper method for constructing exception to indicate that given JSON
+     * Object field name was not in format to be able to deserialize specified
+     * key type.
      */
-    @Deprecated
-    public JsonMappingException endOfInputException(Class<?> instClass) {
-        return JsonMappingException.from(_parser, "Unexpected end-of-input when trying to deserialize a "
-                +instClass.getName());
+    public JsonMappingException unknownTypeIdException(JavaType baseType, String typeId,
+            String extraDesc) {
+        String msg = String.format("Could not resolve type id '%s' into a subtype of %s",
+                typeId, baseType);
+        if (extraDesc != null) {
+            msg = msg + ": "+extraDesc;
+        }
+        return InvalidTypeIdException.from(_parser, msg, baseType, typeId);
     }
-    
+
     /*
     /**********************************************************
     /* Methods for constructing semantic exceptions; mostly
@@ -1200,6 +1204,18 @@ public JsonMappingException unknownTypeException(JavaType type, String id,
         return JsonMappingException.from(_parser, msg);
     }
 
+    /**
+     * Helper method for constructing exception to indicate that end-of-input was
+     * reached while still expecting more tokens to deserialize value of specified type.
+     *
+     * @deprecated Since 2.8; currently no way to catch EOF at databind level
+     */
+    @Deprecated
+    public JsonMappingException endOfInputException(Class<?> instClass) {
+        return JsonMappingException.from(_parser, "Unexpected end-of-input when trying to deserialize a "
+                +instClass.getName());
+    }
+
     /*
     /**********************************************************
     /* Overridable internal methods

src/main/java/com/fasterxml/jackson/databind/exc/InvalidTypeIdException.java

@@ -0,0 +1,53 @@
+package com.fasterxml.jackson.databind.exc;
+
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.databind.JavaType;
+import com.fasterxml.jackson.databind.JsonMappingException;
+
+/**
+ * Exception thrown when resolution of a type id fails.
+ *
+ * @since 2.8
+ */
+public class InvalidTypeIdException extends JsonMappingException
+{
+    private static final long serialVersionUID = 1L; // silly Eclipse, warnings
+
+    /**
+     * Basetype for which subtype was to be resolved
+     */
+    protected final JavaType _baseType;
+
+    /**
+     * Type id that failed to be resolved to a subtype
+     */
+    protected final String _typeId;
+
+    /*
+    /**********************************************************
+    /* Life-cycle
+    /**********************************************************
+     */
+
+    public InvalidTypeIdException(JsonParser p, String msg,
+            JavaType baseType, String typeId)
+    {
+        super(p, msg);
+        _baseType = baseType;
+        _typeId = typeId;
+    }
+
+    public static InvalidTypeIdException from(JsonParser p, String msg,
+            JavaType baseType, String typeId) {
+        return new InvalidTypeIdException(p, msg, baseType, typeId);
+    }
+
+    /*
+    /**********************************************************
+    /* Accessors
+    /**********************************************************
+     */
+
+    public JavaType getBaseType() { return _baseType; }
+    public String getTypeId() { return _typeId; }
+}

src/test/java/com/fasterxml/jackson/databind/filter/ProblemHandlerTest.java

@@ -6,6 +6,7 @@
 import com.fasterxml.jackson.annotation.JsonTypeInfo;
 import com.fasterxml.jackson.databind.*;
 import com.fasterxml.jackson.databind.deser.DeserializationProblemHandler;
+import com.fasterxml.jackson.databind.exc.InvalidTypeIdException;
 
 /**
  * Tests to exercise handler methods of {@link DeserializationProblemHandler}.
@@ -66,6 +67,8 @@ static class BaseWrapper {
     /**********************************************************
      */
 
+    private final ObjectMapper MAPPER = new ObjectMapper();
+
     public void testWeirdKeyHandling() throws Exception
     {
         ObjectMapper mapper = new ObjectMapper()
@@ -86,4 +89,18 @@ public void testInvalidTypeId() throws Exception
                 BaseWrapper.class);
         assertNotNull(w);
     }
+
+    // verify that by default we get special exception type
+    public void testInvalidTypeIdFail() throws Exception
+    {
+        try {
+            MAPPER.readValue("{\"value\":{\"type\":\"foo\",\"a\":4}}",
+                BaseWrapper.class);
+            fail("Should not pass");
+        } catch (InvalidTypeIdException e) {
+            verifyException(e, "Could not resolve type id 'foo'");
+            assertEquals(Base.class, e.getBaseType().getRawClass());
+            assertEquals("foo", e.getTypeId());
+        }
+    }
 }