Initial version of merging-property-deser (#1399)

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

@@ -745,15 +745,6 @@ public AnnotationIntrospector getAnnotationIntrospector()
         return NopAnnotationIntrospector.instance;
     }
 
-    /**
-     * Accessor for getting bean description that only contains class
-     * annotations: useful if no getter/setter/creator information is needed.
-     */
-    @Override
-    public BeanDescription introspectClassAnnotations(JavaType type) {
-        return getClassIntrospector().forClassAnnotations(this, type, this);
-    }
-
     /**
      * Accessor for getting bean description that only contains immediate class
      * annotations: ones from the class, and its direct mix-in, if any, but
@@ -775,32 +766,6 @@ public JsonInclude.Value getDefaultPropertyInclusion() {
         return EMPTY_INCLUDE;
     }
 
-    @Override
-    public JsonInclude.Value getDefaultPropertyInclusion(Class<?> baseType) {
-        ConfigOverride overrides = findConfigOverride(baseType);
-        if (overrides != null) {
-            JsonInclude.Value v = overrides.getInclude();
-            if (v != null) {
-                return v;
-            }
-        }
-        return EMPTY_INCLUDE;
-    }
-
-    @Override
-    public JsonInclude.Value getDefaultPropertyInclusion(Class<?> baseType,
-            JsonInclude.Value defaultIncl)
-    {
-        ConfigOverride overrides = findConfigOverride(baseType);
-        if (overrides != null) {
-            JsonInclude.Value v = overrides.getInclude();
-            if (v != null) {
-                return v;
-            }
-        }
-        return defaultIncl;
-    }
-
     /*
     /**********************************************************
     /* MapperConfig implementation/overrides: other

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

@@ -847,15 +847,6 @@ public AnnotationIntrospector getAnnotationIntrospector()
         return AnnotationIntrospector.nopInstance();
     }
 
-    /**
-     * Accessor for getting bean description that only contains class
-     * annotations: useful if no getter/setter/creator information is needed.
-     */
-    @Override
-    public BeanDescription introspectClassAnnotations(JavaType type) {
-        return getClassIntrospector().forClassAnnotations(this, type, this);
-    }
-
     /**
      * Accessor for getting bean description that only contains immediate class
      * annotations: ones from the class, and its direct mix-in, if any, but
@@ -887,32 +878,6 @@ public JsonInclude.Value getDefaultPropertyInclusion() {
         return _serializationInclusion;
     }
 
-    @Override
-    public JsonInclude.Value getDefaultPropertyInclusion(Class<?> baseType) {
-        ConfigOverride overrides = findConfigOverride(baseType);
-        if (overrides != null) {
-            JsonInclude.Value v = overrides.getInclude();
-            if (v != null) {
-                return v;
-            }
-        }
-        return _serializationInclusion;
-    }
-
-    @Override
-    public JsonInclude.Value getDefaultPropertyInclusion(Class<?> baseType,
-            JsonInclude.Value defaultIncl)
-    {
-        ConfigOverride overrides = findConfigOverride(baseType);
-        if (overrides != null) {
-            JsonInclude.Value v = overrides.getInclude();
-            if (v != null) {
-                return v;
-            }
-        }
-        return defaultIncl;
-    }
-
     /*
     /**********************************************************
     /* Configuration: other

src/main/java/com/fasterxml/jackson/databind/cfg/MapperConfig.java

@@ -319,12 +319,14 @@ public JavaType constructSpecializedType(JavaType baseType, Class<?> subclass) {
     public BeanDescription introspectClassAnnotations(Class<?> cls) {
         return introspectClassAnnotations(constructType(cls));
     }
-    
+
     /**
      * Accessor for getting bean description that only contains class
      * annotations: useful if no getter/setter/creator information is needed.
      */
-    public abstract BeanDescription introspectClassAnnotations(JavaType type);
+    public final BeanDescription introspectClassAnnotations(JavaType type) {
+        return getClassIntrospector().forClassAnnotations(this, type, this);
+    }
 
     /**
      * Accessor for getting bean description that only contains immediate class
@@ -363,7 +365,16 @@ public BeanDescription introspectDirectClassAnnotations(Class<?> cls) {
      *
      * @since 2.7
      */
-    public abstract JsonInclude.Value getDefaultPropertyInclusion(Class<?> baseType);
+    public JsonInclude.Value getDefaultPropertyInclusion(Class<?> baseType) {
+        ConfigOverride overrides = findConfigOverride(baseType);
+        if (overrides != null) {
+            JsonInclude.Value v = overrides.getInclude();
+            if (v != null) {
+                return v;
+            }
+        }
+        return getDefaultPropertyInclusion();
+    }
 
     /**
      * Accessor for default property inclusion to use for serialization,
@@ -374,8 +385,18 @@ public BeanDescription introspectDirectClassAnnotations(Class<?> cls) {
      * 
      * @since 2.8.2
      */
-    public abstract JsonInclude.Value getDefaultPropertyInclusion(Class<?> baseType,
-            JsonInclude.Value defaultIncl);
+    public JsonInclude.Value getDefaultPropertyInclusion(Class<?> baseType,
+            JsonInclude.Value defaultIncl)
+    {
+        ConfigOverride overrides = findConfigOverride(baseType);
+        if (overrides != null) {
+            JsonInclude.Value v = overrides.getInclude();
+            if (v != null) {
+                return v;
+            }
+        }
+        return defaultIncl;
+    }
 
     /**
      * Accessor for default format settings to use for serialization (and, to a degree

src/main/java/com/fasterxml/jackson/databind/deser/BeanDeserializerFactory.java

@@ -509,11 +509,27 @@ protected void addBeanProps(DeserializationContext ctxt,
              *   other types, and only then create constructor parameter, if any.
              */
             if (propDef.hasSetter()) {
-                JavaType propertyType = propDef.getSetter().getParameterType(0);
+                AnnotatedMethod setter = propDef.getSetter();
+                JavaType propertyType = setter.getParameterType(0);
                 prop = constructSettableProperty(ctxt, beanDesc, propDef, propertyType);
+                if (_isMergeableProperty(ctxt, setter, propertyType)) {
+                    AnnotatedMember accessor = propDef.getAccessor();
+                    if (accessor != null) {
+                        accessor.fixAccess(ctxt.isEnabled(MapperFeature.OVERRIDE_PUBLIC_ACCESS_MODIFIERS));
+                        prop = MergingSettableBeanProperty.construct(prop, accessor);
+                    }
+                }
             } else if (propDef.hasField()) {
-                JavaType propertyType = propDef.getField().getType();
+                AnnotatedField field = propDef.getField();
+                JavaType propertyType = field.getType();
                 prop = constructSettableProperty(ctxt, beanDesc, propDef, propertyType);
+                if (_isMergeableProperty(ctxt, field, propertyType)) {
+                    AnnotatedMember accessor = propDef.getAccessor();
+                    if (accessor != null) {
+                        accessor.fixAccess(ctxt.isEnabled(MapperFeature.OVERRIDE_PUBLIC_ACCESS_MODIFIERS));
+                        prop = MergingSettableBeanProperty.construct(prop, accessor);
+                    }
+                }
             } else if (useGettersAsSetters && propDef.hasGetter()) {
                 /* May also need to consider getters
                  * for Map/Collection properties; but with lowest precedence
@@ -570,6 +586,22 @@ protected void addBeanProps(DeserializationContext ctxt,
         }
     }
 
+    protected boolean _isMergeableProperty(DeserializationContext ctxt,
+            AnnotatedMember accessor, JavaType type)
+    {
+        AnnotationIntrospector ai = ctxt.getAnnotationIntrospector();
+        if (ai != null) {
+            JsonSetter.Value setter = ai.findSetterInfo(accessor);
+            if (setter != null) {
+                Boolean b = setter.getMerge();
+                if (b != null) {
+                    return b.booleanValue();
+                }
+            }
+        }
+        return false;
+    }
+
     /**
      * Helper method called to filter out explicit ignored properties,
      * as well as properties that have "ignorable types".

src/main/java/com/fasterxml/jackson/databind/deser/SettableBeanProperty.java

@@ -371,7 +371,7 @@ public boolean hasValueDeserializer() {
     }
 
     public boolean hasValueTypeDeserializer() { return (_valueTypeDeserializer != null); }
-    
+
     public JsonDeserializer<Object> getValueDeserializer() {
         JsonDeserializer<Object> deser = _valueDeserializer;
         if (deser == MISSING_VALUE_DESERIALIZER) {
@@ -485,6 +485,29 @@ public final Object deserialize(JsonParser p, DeserializationContext ctxt) throw
         return _valueDeserializer.deserialize(p, ctxt);
     }
 
+    /**
+     * @since 2.9
+     */
+    public final Object deserializeWith(JsonParser p, DeserializationContext ctxt,
+            Object toUpdate) throws IOException
+    {
+        JsonToken t = p.getCurrentToken();
+
+        // 20-Oct-2016, tatu: Not 100% sure what to do; probably best to simply return
+        //   null value and let caller decide what to do
+        if (t == JsonToken.VALUE_NULL) {
+            return _valueDeserializer.getNullValue(ctxt);
+        }
+        // 20-Oct-2016, tatu: Also tricky -- for now, report an erro
+        if (_valueTypeDeserializer != null) {
+            ctxt.reportBadDefinition(getType(),
+                    String.format("Can not merge polymorphic property '%s'",
+                            getName()));
+//            return _valueDeserializer.deserializeWithType(p, ctxt, _valueTypeDeserializer);
+        }
+        return _valueDeserializer.deserialize(p, ctxt, toUpdate);
+    }
+
     /*
     /**********************************************************
     /* Helper methods

src/main/java/com/fasterxml/jackson/databind/deser/impl/MergingSettableBeanProperty.java

@@ -1,12 +1,9 @@
 package com.fasterxml.jackson.databind.deser.impl;
 
 import java.io.IOException;
-import java.lang.annotation.Annotation;
 
 import com.fasterxml.jackson.core.JsonParser;
 import com.fasterxml.jackson.databind.DeserializationContext;
-import com.fasterxml.jackson.databind.JsonDeserializer;
-import com.fasterxml.jackson.databind.PropertyName;
 import com.fasterxml.jackson.databind.deser.*;
 import com.fasterxml.jackson.databind.introspect.AnnotatedMember;
 
@@ -19,65 +16,44 @@
  * @since 2.9
  */
 public class MergingSettableBeanProperty
-    extends SettableBeanProperty
+    extends SettableBeanProperty.Delegating
 {
     private static final long serialVersionUID = 1L;
 
     /**
-     * Underlying actual property (field- or member-backed).
+     * Member (field, method) used for accessing existing value.
      */
-    protected final SettableBeanProperty _delegate;
+    protected final AnnotatedMember _accessor;
 
     /*
     /**********************************************************
     /* Life-cycle
     /**********************************************************
      */
 
-    public MergingSettableBeanProperty(SettableBeanProperty delegate)
+    protected MergingSettableBeanProperty(SettableBeanProperty delegate,
+            AnnotatedMember accessor)
     {
         super(delegate);
-        _delegate = delegate;
+        _accessor = accessor;
     }
 
     protected MergingSettableBeanProperty(MergingSettableBeanProperty src,
             SettableBeanProperty delegate)
     {
-        super(src);
-        _delegate = src._delegate;
-    }
-
-    @Override
-    public SettableBeanProperty withValueDeserializer(JsonDeserializer<?> deser) {
-        return _new(_delegate.withValueDeserializer(deser));
-    }
-
-    @Override
-    public SettableBeanProperty withName(PropertyName newName) {
-        return _new(_delegate.withName(newName));
-    }
-
-    protected MergingSettableBeanProperty _new(SettableBeanProperty newDelegate) {
-        if (newDelegate == _delegate) {
-            return this;
-        }
-        return new MergingSettableBeanProperty(this, newDelegate);
+        super(delegate);
+        _accessor = src._accessor;
     }
 
-    /*
-    /**********************************************************
-    /* BeanProperty impl
-    /**********************************************************
-     */
-
-    @Override
-    public AnnotatedMember getMember() {
-        return _delegate.getMember();
+    public static MergingSettableBeanProperty construct(SettableBeanProperty delegate,
+            AnnotatedMember accessor)
+    {
+        return new MergingSettableBeanProperty(delegate, accessor);
     }
 
     @Override
-    public <A extends Annotation> A getAnnotation(Class<A> acls) {
-        return _delegate.getAnnotation(acls);
+    protected SettableBeanProperty withDelegate(SettableBeanProperty d) {
+        return new MergingSettableBeanProperty(d, _accessor);
     }
 
     /*
@@ -90,25 +66,39 @@ public <A extends Annotation> A getAnnotation(Class<A> acls) {
     public void deserializeAndSet(JsonParser p, DeserializationContext ctxt,
             Object instance) throws IOException
     {
-        // TODO Auto-generated method stub
+        delegate.set(instance, _deserialize(p, ctxt, instance));
     }
 
     @Override
     public Object deserializeSetAndReturn(JsonParser p,
             DeserializationContext ctxt, Object instance) throws IOException {
-        // TODO Auto-generated method stub
-        return null;
+        return delegate.setAndReturn(instance, _deserialize(p, ctxt, instance));
     }
 
     @Override
     public void set(Object instance, Object value) throws IOException {
-        // TODO Auto-generated method stub
+        delegate.set(instance, value);
     }
 
     @Override
     public Object setAndReturn(Object instance, Object value)
-            throws IOException {
-        // TODO Auto-generated method stub
-        return null;
+            throws IOException
+    {
+        return delegate.setAndReturn(instance, value);
+    }
+
+    protected Object _deserialize(JsonParser p, DeserializationContext ctxt,
+            Object instance) throws IOException
+    {
+        Object value = _accessor.getValue(instance);
+        // 20-Oct-2016, tatu: Couple of possibilities of how to proceed; for
+        //    now, default to "normal" handling without merging
+        if (value == null) {
+            return delegate.deserialize(p, ctxt);
+        }
+        Object result = delegate.deserializeWith(p,  ctxt,  value);
+        // 20-Oct-2016, tatu: Similarly, we may get same object or different one;
+        //   whether to return original or new is an open question.
+        return result;
     }
 }