Polished PR #4 and documentation.

Reverted ea29311 for now.

src/main/java/com/github/jonpeterson/jackson/module/versioning/JsonVersionedModel.java

@@ -44,11 +44,17 @@
     String currentVersion();
 
     /**
-     * @return the version to convert the model to during serialization; this can be overridden by using
-     *         {@link JsonSerializeToVersion}
+     * @return the default version to convert the model to during serialization when no field or getter method is
+     *         annotated with {@link JsonSerializeToVersion}; if not set, the current version is used
      */
     String defaultSerializeToVersion() default "";
 
+    /**
+     * @return the default version to convert the model to during deserialization when no model version property is
+     *         present; if not set, an exception is thrown when the model version property is missing
+     */
+    String defaultDeserializeToVersion() default "";
+
     /**
      * @return class of the converter to use when resolving versioning to the current version; not specifying will cause
      *         models to not be converted at all
@@ -71,9 +77,4 @@
      * @return name of property in which the model's version is stored in JSON
      */
     String propertyName() default "modelVersion";
-
-    /**
-     * @return the default version to use if the propertyName() attribute is not available.
-     */
-    String defaultDeserializeToVersion() default "";
 }

src/main/java/com/github/jonpeterson/jackson/module/versioning/VersionedModelDeserializer.java

@@ -48,18 +48,7 @@ class VersionedModelDeserializer<T> extends StdDeserializer<T> implements Resolv
         this.delegate = delegate;
         this.jsonVersionedModel = jsonVersionedModel;
         this.serializeToVersionProperty = serializeToVersionProperty;
-
-        if(serializeToVersionProperty != null) {
-            JsonSerializeToVersion annotatedJsonSerializeToVersion = serializeToVersionProperty.getAccessor().getAnnotation(JsonSerializeToVersion.class);
-
-            //Allow the field to be annotated and not just the accessor
-            if(annotatedJsonSerializeToVersion == null) {
-                annotatedJsonSerializeToVersion = serializeToVersionProperty.getField().getAnnotation(JsonSerializeToVersion.class);
-            }
-            this.serializeToVersionAnnotation = annotatedJsonSerializeToVersion;
-        } else {
-            this.serializeToVersionAnnotation = null;
-        }
+        this.serializeToVersionAnnotation = serializeToVersionProperty != null ? serializeToVersionProperty.getAccessor().getAnnotation(JsonSerializeToVersion.class) : null;
 
         Class<? extends VersionedModelConverter> converterClass = jsonVersionedModel.toCurrentConverterClass();
         if(converterClass != VersionedModelConverter.class)
@@ -88,15 +77,16 @@ public T deserialize(JsonParser parser, DeserializationContext context) throws I
         ObjectNode modelData = (ObjectNode)jsonNode;
 
         JsonNode modelVersionNode = modelData.remove(jsonVersionedModel.propertyName());
-        String modelVersion;
-        if(modelVersionNode == null) {
-            modelVersion = jsonVersionedModel.defaultDeserializeToVersion();
-        } else {
+
+        String modelVersion = null;
+        if(modelVersionNode != null)
             modelVersion = modelVersionNode.asText();
-        }
-
+
         if(modelVersion == null)
-            throw context.mappingException("'" + jsonVersionedModel.propertyName() + "' property was null");
+            modelVersion = jsonVersionedModel.defaultDeserializeToVersion();
+
+        if(modelVersion.isEmpty())
+            throw context.mappingException("'" + jsonVersionedModel.propertyName() + "' property was null and defaultDeserializeToVersion was not set");
 
         // convert the model if converter specified and model needs converting
         if(converter != null && (jsonVersionedModel.alwaysConvert() || !modelVersion.equals(jsonVersionedModel.currentVersion())))

src/main/java/com/github/jonpeterson/jackson/module/versioning/VersionedModelSerializer.java

@@ -111,11 +111,9 @@ private void doSerialize(T value, JsonGenerator generator, SerializerProvider pr
         if(converter != null && (jsonVersionedModel.alwaysConvert() || !targetVersion.equals(jsonVersionedModel.currentVersion())))
             modelData = converter.convert(modelData, jsonVersionedModel.currentVersion(), targetVersion, JsonNodeFactory.instance);
 
-        // add target version to model data if it wasn't the default
-        if(!targetVersion.equals(jsonVersionedModel.defaultDeserializeToVersion())) {
-            modelData.put(jsonVersionedModel.propertyName(), targetVersion);
-        }
-
+        // add target version to model data
+        modelData.put(jsonVersionedModel.propertyName(), targetVersion);
+
         // write node
         generator.writeTree(modelData);
     }

src/main/java/com/github/jonpeterson/jackson/module/versioning/VersionedModelUtils.java

@@ -24,7 +24,6 @@
 package com.github.jonpeterson.jackson.module.versioning;
 
 import com.fasterxml.jackson.databind.BeanDescription;
-import com.fasterxml.jackson.databind.introspect.AnnotatedField;
 import com.fasterxml.jackson.databind.introspect.AnnotatedMember;
 import com.fasterxml.jackson.databind.introspect.BeanPropertyDefinition;
 
@@ -34,9 +33,7 @@ public static BeanPropertyDefinition getSerializeToVersionProperty(BeanDescripti
         BeanPropertyDefinition serializeToVersionProperty = null;
         for(BeanPropertyDefinition definition: beanDescription.findProperties()) {
             AnnotatedMember accessor = definition.getAccessor();
-            AnnotatedField field = definition.getField();
-
-            if((accessor != null && accessor.hasAnnotation(JsonSerializeToVersion.class)) || (field != null && field.hasAnnotation(JsonSerializeToVersion.class))) {
+            if(accessor != null && accessor.hasAnnotation(JsonSerializeToVersion.class)) {
                 if(serializeToVersionProperty != null)
                     throw new RuntimeException("@" + JsonSerializeToVersion.class.getSimpleName() + " must be present on at most one field or method");
                 if(accessor.getRawType() != String.class || (definition.getField() == null && !definition.hasGetter()))

src/test/groovy/com/github/jonpeterson/jackson/module/versioning/VersioningModuleTest.groovy

@@ -26,6 +26,7 @@ package com.github.jonpeterson.jackson.module.versioning
 import com.fasterxml.jackson.annotation.JsonIgnore
 import com.fasterxml.jackson.annotation.JsonSubTypes
 import com.fasterxml.jackson.annotation.JsonTypeInfo
+import com.fasterxml.jackson.databind.JsonMappingException
 import com.fasterxml.jackson.databind.ObjectMapper
 import com.fasterxml.jackson.databind.node.JsonNodeFactory
 import com.fasterxml.jackson.databind.node.ObjectNode
@@ -58,6 +59,12 @@ class VersioningModuleTest extends Specification {
         String _debugPreDeserializationVersion
     }
 
+    @JsonVersionedModel(currentVersion = '3',
+                        toCurrentConverterClass = ToCurrentCarConverter,
+                        defaultDeserializeToVersion = '1')
+    static class DefaultDeserializeToCar extends Car {
+    }
+
     @JsonVersionedModel(currentVersion = '3',
                         defaultSerializeToVersion = '2',
                         toCurrentConverterClass = ToCurrentCarConverter,
@@ -384,7 +391,7 @@ class VersioningModuleTest extends Specification {
     }
 
     @Unroll
-    def 'abc #clazz.simpleName'() {
+    def 'serialize with source version #clazz.simpleName'() {
         when:
         def car = mapper.readValue('{"model": "toyota:camry", "year": 2012, "new": "false", "_version": "1"}', clazz)
         car.year = 2013
@@ -400,6 +407,31 @@ class VersioningModuleTest extends Specification {
         SourceVersionMethodSerializeToCar | [_version: '1', model: 'toyota:camry', new: 'false', year: 2013, _debugPreDeserializationVersion: '1', _debugPreSerializationVersion: '3']
     }
 
+    @Unroll
+    def 'missing version'() {
+        when: 'no version specified'
+        mapper.readValue('{"model": "toyota:camry", "year": 2012, "new": "false"}', Car)
+
+        then: 'throw exception since no defaultDeserializeToVersion on Car'
+        thrown JsonMappingException
+
+
+        when: 'no version specified'
+        def car = mapper.readValue('{"model": "toyota:camry", "year": 2012, "new": "false"}', DefaultDeserializeToCar)
+
+        then: 'treat it as version 1 as specified by defaultDeserializeToVersion on DefaultDeserializeToCar'
+        // using write->read instead of convert method due to Jackson 2.2 bug
+        mapper.readValue(mapper.writeValueAsString(car), Map) == [
+            make: 'toyota',
+            model: 'camry',
+            modelVersion: '3',
+            used: true,
+            year: 2012,
+            _debugPreDeserializationVersion: '1',
+            _debugPreSerializationVersion: null
+        ]
+    }
+
     def 'errors'() {
         when:
         mapper.writeValueAsString(clazz.newInstance())