Fix FasterXML#998

Author: cowtowncoder

release-notes/VERSION

@@ -30,6 +30,7 @@ Project: jackson-databind
 #957: Merge `datatype-jdk7` stuff in (java.nio.file.Path handling)
 #959: Schema generation: consider active view, discard non-included properties
 #997: Add `MapperFeature.OVERRIDE_PUBLIC_ACCESS_MODIFIERS`
+#998: Allow use of `NON_DEFAULT` for POJOs without default constructor
 - Make `JsonValueFormat` (self-)serializable, deserializable, to/from valid external
   value (as per JSON Schema spec)
 

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

@@ -224,7 +224,7 @@ protected BeanDescription(JavaType type) {
      */
 
     public abstract Map<Object, AnnotatedMember> findInjectables();
-    
+
     /**
      * Method for checking if the POJO type has annotations to
      * indicate that a builder is to be used for instantiating
@@ -237,7 +237,7 @@ protected BeanDescription(JavaType type) {
      * Method for finding configuration for POJO Builder class.
      */
     public abstract JsonPOJOBuilder.Value findPOJOBuilderConfig();
-    
+
     /**
      * Method called to create a "default instance" of the bean, currently
      * only needed for obtaining default field values which may be used for

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

@@ -298,8 +298,7 @@ public List<AnnotatedConstructor> getConstructors() {
     }
 
     @Override
-    public Object instantiateBean(boolean fixAccess)
-    {
+    public Object instantiateBean(boolean fixAccess) {
         AnnotatedConstructor ac = _classInfo.getDefaultConstructor();
         if (ac == null) {
             return null;

src/main/java/com/fasterxml/jackson/databind/ser/PropertyBuilder.java

@@ -14,6 +14,9 @@
  */
 public class PropertyBuilder
 {
+    // @since 2.7
+    private final static Object NO_DEFAULT_MARKER = Boolean.FALSE;
+    
     final protected SerializationConfig _config;
     final protected BeanDescription _beanDesc;
 
@@ -222,22 +225,39 @@ protected JavaType findSerializationType(Annotated a, boolean useStaticTyping, J
 
     protected Object getDefaultBean()
     {
-        if (_defaultBean == null) {
+        Object def = _defaultBean;
+        if (def == null) {
             /* If we can fix access rights, we should; otherwise non-public
              * classes or default constructor will prevent instantiation
              */
-            _defaultBean = _beanDesc.instantiateBean(_config.canOverrideAccessModifiers());
-            if (_defaultBean == null) {
+            def = _beanDesc.instantiateBean(_config.canOverrideAccessModifiers());
+            if (def == null) {
+                // 06-Nov-2015, tatu: As per [databind#998], do not fail.
+                /*
                 Class<?> cls = _beanDesc.getClassInfo().getAnnotated();
                 throw new IllegalArgumentException("Class "+cls.getName()+" has no default constructor; can not instantiate default bean value to support 'properties=JsonSerialize.Inclusion.NON_DEFAULT' annotation");
+                 */
+
+                // And use a marker
+                def = NO_DEFAULT_MARKER;
             }
+            _defaultBean = def;
         }
-        return _defaultBean;
+        return (def == NO_DEFAULT_MARKER) ? null : _defaultBean;
     }
 
     protected Object getDefaultValue(String name, AnnotatedMember member)
     {
         Object defaultBean = getDefaultBean();
+        if (defaultBean == null) {
+            // 06-Nov-2015, tatu: Returning null is fine for Object types; but need special
+            //   handling for primitives since they are never passed as nulls.
+            Class<?> cls = member.getRawType();
+            if (cls.isPrimitive()) {
+                return ClassUtil.defaultValue(cls);
+            }
+            return null;
+        }
         try {
             return member.getValue(defaultBean);
         } catch (Exception e) {

src/test/java/com/fasterxml/jackson/databind/ser/TestNullProperties.java renamed to src/test/java/com/fasterxml/jackson/databind/filter/JsonIncludeTest.java

@@ -1,9 +1,10 @@
-package com.fasterxml.jackson.databind.ser;
+package com.fasterxml.jackson.databind.filter;
 
 import java.io.IOException;
 import java.util.*;
 
 import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 import com.fasterxml.jackson.databind.*;
 import com.fasterxml.jackson.databind.annotation.JsonSerialize;
 
@@ -12,15 +13,9 @@
  * {@link JsonSerialize#include} annotation property work
  * as expected.
  */
-public class TestNullProperties
+public class JsonIncludeTest
     extends BaseMapTest
 {
-    /*
-    /**********************************************************
-    /* Helper beans
-    /**********************************************************
-     */
-
     static class SimpleBean
     {
         public String getA() { return "a"; }
@@ -47,6 +42,23 @@ static class NonDefaultBean
         public String getB() { return _b; }
     }
 
+    // [databind#998]: Do not require no-arg constructor; but if not, defaults check
+    //    has weaker interpretation
+    @JsonPropertyOrder({ "x", "y", "z" })
+    @JsonInclude(JsonInclude.Include.NON_DEFAULT)
+    static class NonDefaultBeanXYZ
+    {
+        public int x;
+        public int y = 3;
+        public int z = 7;
+
+        NonDefaultBeanXYZ(int x, int y, int z) {
+            this.x = x;
+            this.y = y;
+            this.z = z;
+        }
+    }
+    
     static class MixedBean
     {
         String _a = "a", _b = "b";
@@ -76,11 +88,12 @@ static class ArrayBean {
     /* Unit tests
     /**********************************************************
      */
-    
+
+    final private ObjectMapper MAPPER = new ObjectMapper();
+
     public void testGlobal() throws IOException
     {
-        ObjectMapper m = new ObjectMapper();
-        Map<String,Object> result = writeAndMap(m, new SimpleBean());
+        Map<String,Object> result = writeAndMap(MAPPER, new SimpleBean());
         assertEquals(2, result.size());
         assertEquals("a", result.get("a"));
         assertNull(result.get("b"));
@@ -89,8 +102,7 @@ public void testGlobal() throws IOException
 
     public void testNonNullByClass() throws IOException
     {
-        ObjectMapper m = new ObjectMapper();
-        Map<String,Object> result = writeAndMap(m, new NoNullsBean());
+        Map<String,Object> result = writeAndMap(MAPPER, new NoNullsBean());
         assertEquals(1, result.size());
         assertFalse(result.containsKey("a"));
         assertNull(result.get("a"));
@@ -100,48 +112,51 @@ public void testNonNullByClass() throws IOException
 
     public void testNonDefaultByClass() throws IOException
     {
-        ObjectMapper m = new ObjectMapper();
         NonDefaultBean bean = new NonDefaultBean();
         // need to change one of defaults
         bean._a = "notA";
-        Map<String,Object> result = writeAndMap(m, bean);
+        Map<String,Object> result = writeAndMap(MAPPER, bean);
         assertEquals(1, result.size());
         assertTrue(result.containsKey("a"));
         assertEquals("notA", result.get("a"));
         assertFalse(result.containsKey("b"));
         assertNull(result.get("b"));
     }
 
+    // [databind#998]
+    public void testNonDefaultByClassNoCtor() throws IOException
+    {
+        NonDefaultBeanXYZ bean = new NonDefaultBeanXYZ(1, 2, 0);
+        String json = MAPPER.writeValueAsString(bean);
+        assertEquals(aposToQuotes("{'x':1,'y':2}"), json);
+    }
+    
     public void testMixedMethod() throws IOException
     {
-        ObjectMapper m = new ObjectMapper();
-
         MixedBean bean = new MixedBean();
         bean._a = "xyz";
         bean._b = null;
-        Map<String,Object> result = writeAndMap(m, bean);
+        Map<String,Object> result = writeAndMap(MAPPER, bean);
         assertEquals(1, result.size());
         assertEquals("xyz", result.get("a"));
         assertFalse(result.containsKey("b"));
 
         bean._a = "a";
         bean._b = "b";
-        result = writeAndMap(m, bean);
+        result = writeAndMap(MAPPER, bean);
         assertEquals(1, result.size());
         assertEquals("b", result.get("b"));
         assertFalse(result.containsKey("a"));
     }
 
     public void testDefaultForEmptyList() throws IOException
     {
-        ObjectMapper m = new ObjectMapper();
-        assertEquals("{}", m.writeValueAsString(new ListBean()));
+        assertEquals("{}", MAPPER.writeValueAsString(new ListBean()));
     }
 
-    // [JACKSON-531]: make NON_DEFAULT work for arrays too
+    // NON_DEFAULT shoud work for arrays too
     public void testNonEmptyDefaultArray() throws IOException
     {
-        ObjectMapper m = new ObjectMapper();
-        assertEquals("{}", m.writeValueAsString(new ArrayBean()));
+        assertEquals("{}", MAPPER.writeValueAsString(new ArrayBean()));
     }
 }

src/test/java/com/fasterxml/jackson/databind/ser/TestNullSerialization.java renamed to src/test/java/com/fasterxml/jackson/databind/filter/NullSerializationTest.java

@@ -1,22 +1,24 @@
-package com.fasterxml.jackson.databind.ser;
+package com.fasterxml.jackson.databind.filter;
 
 import java.io.*;
 
 import com.fasterxml.jackson.core.*;
 import com.fasterxml.jackson.databind.*;
 import com.fasterxml.jackson.databind.annotation.JsonSerialize;
 import com.fasterxml.jackson.databind.node.ObjectNode;
+import com.fasterxml.jackson.databind.ser.DefaultSerializerProvider;
+import com.fasterxml.jackson.databind.ser.SerializerFactory;
 
-public class TestNullSerialization
+public class NullSerializationTest
     extends BaseMapTest
 {
     static class NullSerializer extends JsonSerializer<Object>
     {
         @Override
-        public void serialize(Object value, JsonGenerator jgen, SerializerProvider provider)
-            throws IOException, JsonProcessingException
+        public void serialize(Object value, JsonGenerator gen, SerializerProvider provider)
+            throws IOException
         {
-            jgen.writeString("foobar");
+            gen.writeString("foobar");
         }
     }