add testcase & refactor & bug fix

benchmark/src/main/java/com/alibaba/fastjson2/benchmark/eishay/mixin/ImageMixin.java

@@ -7,15 +7,14 @@ import com.alibaba.fastjson2.reader.ObjectReaders;
 import com.alibaba.fastjson2.writer.ObjectWriter;
 import com.alibaba.fastjson2.writer.ObjectWriters;
 
-import static com.alibaba.fastjson2.reader.ObjectReaders.fieldReader;
+import static com.alibaba.fastjson2.reader.ObjectReaders.*;
-import static com.alibaba.fastjson2.reader.ObjectReaders.fieldReaderInt;
 
 @JSONAutowired
 public class ImageMixin {
     public static final ObjectWriter<Image> objectWriter = ObjectWriters.objectWriter(
             Image.class,
             ObjectWriters.fieldWriter("height", Image::getHeight),
-            ObjectWriters.fieldWriter("size", Image.Size.class, (Image e) -> e.getSize()),
+            ObjectWriters.fieldWriter("size", Image.Size.class, Image::getSize),
             ObjectWriters.fieldWriter("title", Image::getTitle),
             ObjectWriters.fieldWriter("uri", Image::getUri),
             ObjectWriters.fieldWriter("width", Image::getWidth)
@@ -24,9 +23,9 @@ public class ImageMixin {
     public static final ObjectReader<Image> objectReader = ObjectReaders.of(
             Image::new,
             fieldReaderInt("height", Image::setHeight),
-            fieldReader("size", Image.Size.class, (Image o, Image.Size v) -> o.setSize(v)),
+            fieldReader("size", Image.Size.class, Image::setSize),
-            fieldReader("title", String.class, (Image o, String v) -> o.setTitle(v)),
+            fieldReaderString("title", Image::setTitle),
-            fieldReader("uri", String.class, (Image o, String v) -> o.setUri(v)),
+            fieldReaderString("uri", Image::setUri),
             fieldReaderInt("width", Image::setWidth)
     );
 }

benchmark/src/main/java/com/alibaba/fastjson2/benchmark/eishay/mixin/MediaContentMixin.java

@@ -10,7 +10,6 @@ import com.alibaba.fastjson2.writer.ObjectWriter;
 import com.alibaba.fastjson2.writer.ObjectWriters;
 
 import java.util.ArrayList;
-import java.util.List;
 
 import static com.alibaba.fastjson2.reader.ObjectReaders.*;
 
@@ -18,13 +17,13 @@ import static com.alibaba.fastjson2.reader.ObjectReaders.*;
 public class MediaContentMixin {
     public static final ObjectWriter<MediaContent> objectWriter = ObjectWriters.objectWriter(
             MediaContent.class,
-            ObjectWriters.fieldWriter("media", Media.class, (MediaContent e) -> e.getMedia()),
+            ObjectWriters.fieldWriter("media", Media.class, MediaContent::getMedia),
-            ObjectWriters.fieldWriterList("images", Image.class, (MediaContent e) -> e.getImages())
+            ObjectWriters.fieldWriterList("images", Image.class, MediaContent::getImages)
     );
 
     public static final ObjectReader<MediaContent> objectReader = ObjectReaders.of(
             MediaContent::new,
-            fieldReader("media", Media.class, (MediaContent o, Media v) -> o.setMedia(v)),
+            fieldReader("media", Media.class, MediaContent::setMedia),
-            fieldReaderList("images", Image.class, ArrayList::new, (MediaContent o, List<Image> v) -> o.setImages(v))
+            fieldReaderList("images", Image.class, ArrayList::new, MediaContent::setImages)
     );
 }

benchmark/src/main/java/com/alibaba/fastjson2/benchmark/eishay/mixin/MediaMixin.java

@@ -7,26 +7,23 @@ import com.alibaba.fastjson2.reader.ObjectReaders;
 import com.alibaba.fastjson2.writer.ObjectWriter;
 import com.alibaba.fastjson2.writer.ObjectWriters;
 
-import java.util.ArrayList;
-import java.util.List;
-
 import static com.alibaba.fastjson2.reader.ObjectReaders.*;
 
 @JSONAutowired
 public class MediaMixin {
     public static final ObjectWriter<Media> objectWriter = ObjectWriters.objectWriter(
             Media.class,
-            ObjectWriters.fieldWriter("bitrate", (Media e) -> e.getBitrate()),
+            ObjectWriters.fieldWriter("bitrate", Media::getBitrate),
-            ObjectWriters.fieldWriter("duration", (Media e) -> e.getDuration()),
+            ObjectWriters.fieldWriter("duration", Media::getDuration),
-            ObjectWriters.fieldWriter("format", (Media e) -> e.getFormat()),
+            ObjectWriters.fieldWriter("format", Media::getFormat),
-            ObjectWriters.fieldWriter("height", (Media e) -> e.getHeight()),
+            ObjectWriters.fieldWriter("height", Media::getHeight),
-            ObjectWriters.fieldWriterList("persons", String.class, (Media e) -> e.getPersons()),
+            ObjectWriters.fieldWriterListString("persons", Media::getPersons),
-            ObjectWriters.fieldWriter("player", Media.Player.class, (Media e) -> e.getPlayer()),
+            ObjectWriters.fieldWriter("player", Media.Player.class, Media::getPlayer),
-            ObjectWriters.fieldWriter("size", (Media e) -> e.getSize()),
+            ObjectWriters.fieldWriter("size", Media::getSize),
-            ObjectWriters.fieldWriter("title", (Media e) -> e.getTitle()),
+            ObjectWriters.fieldWriter("title", Media::getTitle),
-            ObjectWriters.fieldWriter("uri", (Media e) -> e.getUri()),
+            ObjectWriters.fieldWriter("uri", Media::getUri),
-            ObjectWriters.fieldWriter("width", (Media e) -> e.getWidth()),
+            ObjectWriters.fieldWriter("width", Media::getWidth),
-            ObjectWriters.fieldWriter("copyright", (Media e) -> e.getCopyright())
+            ObjectWriters.fieldWriter("copyright", Media::getCopyright)
     );
 
     public static final ObjectReader<Media> objectReader = ObjectReaders.of(
@@ -35,8 +32,8 @@ public class MediaMixin {
             fieldReaderLong("duration", Media::setDuration),
             fieldReaderString("format", Media::setFormat),
             fieldReaderInt("height", Media::setHeight),
-            fieldReaderList("persons", String.class, ArrayList::new, (Media o, List<String> v) -> o.setPersons(v)),
+            fieldReaderListStr("persons", Media::setPersons),
-            fieldReader("player", Media.Player.class, (Media o, Media.Player v) -> o.setPlayer(v)),
+            fieldReader("player", Media.Player.class, Media::setPlayer),
             fieldReaderLong("size", Media::setSize),
             fieldReaderString("title", Media::setTitle),
             fieldReaderString("uri", Media::setUri),

core/src/main/java/com/alibaba/fastjson2/reader/ObjectReaderCreator.java

@@ -2508,7 +2508,13 @@ public class ObjectReaderCreator {
         Class fieldClassResolved = null;
 
         if (!(fieldType instanceof Class)) {
-            fieldTypeResolved = BeanUtils.getFieldType(TypeReference.get(objectType), objectClass, method, fieldType);
+            TypeReference<?> objectTypeReference;
+            if (objectType == null) {
+                objectTypeReference = null;
+            } else {
+                objectTypeReference = TypeReference.get(objectType);
+            }
+            fieldTypeResolved = BeanUtils.getFieldType(objectTypeReference, objectClass, method, fieldType);
             fieldClassResolved = TypeUtils.getMapping(fieldTypeResolved);
         }
 

core/src/main/java/com/alibaba/fastjson2/reader/ObjectReaders.java

@@ -56,7 +56,11 @@ public class ObjectReaders {
     public static <T> ObjectReader<T> objectReader(
             Function<Map<Long, Object>, T> creator,
             FieldReader... fieldReaders) {
-        return ObjectReaderCreator.INSTANCE.createObjectReaderNoneDefaultConstructor(null, creator, fieldReaders);
+        return ObjectReaderCreator.INSTANCE.createObjectReaderNoneDefaultConstructor(
+                null,
+                creator,
+                fieldReaders
+        );
     }
 
     public static FieldReader fieldReader(String fieldName, Class fieldClass) {
@@ -151,6 +155,13 @@ public class ObjectReaders {
         return new FieldReaderListFuncImpl<>(listCreator, null, function, itemType, fieldName);
     }
 
+    public static <T> FieldReader fieldReaderListStr(
+            String fieldName,
+            BiConsumer<T, List<String>> function
+    ) {
+        return new FieldReaderListFuncImpl<>(ArrayList::new, null, function, String.class, fieldName);
+    }
+
     public static <T, V> FieldReader fieldReaderList(
             String fieldName,
             Type itemType,

core/src/main/java/com/alibaba/fastjson2/util/BeanUtils.java

@@ -1480,15 +1480,21 @@ public abstract class BeanUtils {
         }
     }
 
-    public static Type getFieldType(TypeReference type, Class<?> raw, Member field, Type fieldType) {
+    public static Type getFieldType(TypeReference typeReference, Class<?> raw, Member field, Type fieldType) {
-        Class<?> declaringClass = field.getDeclaringClass();
+        Class<?> declaringClass;
+        if (field == null) {
+            declaringClass = null;
+        } else {
+            declaringClass = field.getDeclaringClass();
+        }
 
         while (raw != Object.class) {
+            Type type = typeReference == null ? null : typeReference.getType();
             if (declaringClass == raw) {
-                return resolve(type.getType(), declaringClass, fieldType);
+                return resolve(type, declaringClass, fieldType);
             }
-            type = TypeReference.get(resolve(type.getType(), raw, raw.getGenericSuperclass()));
+            typeReference = TypeReference.get(resolve(type, raw, raw.getGenericSuperclass()));
-            raw = type.getRawType();
+            raw = typeReference.getRawType();
         }
         return null;
     }

core/src/main/java/com/alibaba/fastjson2/writer/ObjectWriters.java

@@ -5,7 +5,9 @@ import com.alibaba.fastjson2.function.ToByteFunction;
 import com.alibaba.fastjson2.function.ToFloatFunction;
 import com.alibaba.fastjson2.function.ToShortFunction;
 import com.alibaba.fastjson2.util.ParameterizedTypeImpl;
+import com.alibaba.fastjson2.util.TypeUtils;
 
+import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
 import java.util.List;
 import java.util.function.*;
@@ -25,7 +27,7 @@ public class ObjectWriters {
         return INSTANCE.createObjectWriter(objectType, fieldWriters);
     }
 
-    public static ObjectWriter of(Class objectType, FieldWriter... fieldWriters) {
+    public static <T> ObjectWriter<T> of(Class<T> objectType, FieldWriter... fieldWriters) {
         return INSTANCE.createObjectWriter(objectType, fieldWriters);
     }
 
@@ -124,6 +126,16 @@ public class ObjectWriters {
     }
 
     public static <T, V> FieldWriter fieldWriterList(String fieldName, Class<V> itemType, Function<T, List<V>> function) {
-        return INSTANCE.createFieldWriter(fieldName, new ParameterizedTypeImpl(List.class, itemType), List.class, function);
+        ParameterizedType listType;
+        if (itemType == String.class) {
+            listType = TypeUtils.PARAM_TYPE_LIST_STR;
+        } else {
+            listType = new ParameterizedTypeImpl(List.class, itemType);
+        }
+        return INSTANCE.createFieldWriter(fieldName, listType, List.class, function);
+    }
+
+    public static <T> FieldWriter fieldWriterListString(String fieldName, Function<T, List<String>> function) {
+        return INSTANCE.createFieldWriter(fieldName, TypeUtils.PARAM_TYPE_LIST_STR, List.class, function);
     }
 }

core/src/test/java/com/alibaba/fastjson2/reader/ObjectReadersTest.java

@@ -2,8 +2,10 @@ package com.alibaba.fastjson2.reader;
 
 import com.alibaba.fastjson2.JSONReader;
 import com.alibaba.fastjson2.util.Fnv;
+import com.alibaba.fastjson2.util.TypeUtils;
 import org.junit.jupiter.api.Test;
 
+import java.util.List;
 import java.util.Map;
 import java.util.function.Function;
 
@@ -143,6 +145,17 @@ public class ObjectReadersTest {
         assertEquals("12.34", bean.value);
     }
 
+    @Test
+    public void testString_1() {
+        ObjectReader<Bean5> objectReader = ObjectReaders.objectReader(
+                Bean5.class,
+                Bean5::new,
+                fieldReader("value", String.class, String.class, Bean5::setValue)
+        );
+        Bean5 bean = objectReader.readObject(JSONReader.of("{\"value\":\"12.34\"}"));
+        assertEquals("12.34", bean.value);
+    }
+
     static class Bean5 {
         private String value;
 
@@ -154,4 +167,55 @@ public class ObjectReadersTest {
             this.value = value;
         }
     }
+
+    @Test
+    public void testList() {
+        ObjectReader<Bean6> objectReader = ObjectReaders.objectReader(
+                Bean6.class,
+                Bean6::new,
+                fieldReaderListStr("value", Bean6::setValues)
+        );
+        Bean6 bean = objectReader.readObject(JSONReader.of("{\"value\":[\"12\",\"34\"]}"));
+        assertEquals(2, bean.values.size());
+        assertEquals("12", bean.values.get(0));
+        assertEquals("34", bean.values.get(1));
+    }
+
+    @Test
+    public void testList_1() {
+        ObjectReader<Bean6> objectReader = ObjectReaders.objectReader(
+                Bean6.class,
+                Bean6::new,
+                fieldReaderList("value", String.class, Bean6::setValues)
+        );
+        Bean6 bean = objectReader.readObject(JSONReader.of("{\"value\":[\"12\",\"34\"]}"));
+        assertEquals(2, bean.values.size());
+        assertEquals("12", bean.values.get(0));
+        assertEquals("34", bean.values.get(1));
+    }
+
+    @Test
+    public void testList_2() {
+        ObjectReader<Bean6> objectReader = ObjectReaders.objectReader(
+                Bean6.class,
+                Bean6::new,
+                fieldReader("value", TypeUtils.PARAM_TYPE_LIST_STR, List.class, Bean6::setValues)
+        );
+        Bean6 bean = objectReader.readObject(JSONReader.of("{\"value\":[\"12\",\"34\"]}"));
+        assertEquals(2, bean.values.size());
+        assertEquals("12", bean.values.get(0));
+        assertEquals("34", bean.values.get(1));
+    }
+
+    static class Bean6 {
+        private List<String> values;
+
+        public List<String> getValues() {
+            return values;
+        }
+
+        public void setValues(List<String> values) {
+            this.values = values;
+        }
+    }
 }

core/src/test/java/com/alibaba/fastjson2/writer/ObjectWritersTest.java

@@ -1,13 +1,15 @@
 package com.alibaba.fastjson2.writer;
 
 import com.alibaba.fastjson2.JSONWriter;
+import com.alibaba.fastjson2.util.TypeUtils;
 import org.junit.jupiter.api.Test;
 
+import java.util.ArrayList;
+import java.util.List;
 import java.util.function.ToIntFunction;
 import java.util.function.ToLongFunction;
 
-import static com.alibaba.fastjson2.writer.ObjectWriters.fieldWriter;
+import static com.alibaba.fastjson2.writer.ObjectWriters.*;
-import static com.alibaba.fastjson2.writer.ObjectWriters.objectWriter;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 public class ObjectWritersTest {
@@ -114,4 +116,173 @@ public class ObjectWritersTest {
             return id;
         }
     }
+
+    @Test
+    public void test3() throws Exception {
+        ObjectWriter<Bean3> objectWriter = ObjectWriters.of(
+                Bean3.class,
+                fieldWriterListString("names", Bean3::getNames)
+        );
+
+        Bean3 bean = new Bean3();
+        bean.names = new ArrayList<>();
+        bean.names.add("1");
+        bean.names.add("2");
+        JSONWriter jsonWriter = JSONWriter.of();
+        objectWriter.write(jsonWriter, bean);
+        assertEquals("{\"names\":[\"1\",\"2\"]}", jsonWriter.toString());
+    }
+
+    @Test
+    public void test3_1() throws Exception {
+        ObjectWriter<Bean3> objectWriter = ObjectWriters.of(
+                Bean3.class,
+                fieldWriterList("names", String.class, Bean3::getNames)
+        );
+
+        Bean3 bean = new Bean3();
+        bean.names = new ArrayList<>();
+        bean.names.add("1");
+        bean.names.add("2");
+        JSONWriter jsonWriter = JSONWriter.of();
+        objectWriter.write(jsonWriter, bean);
+        assertEquals("{\"names\":[\"1\",\"2\"]}", jsonWriter.toString());
+    }
+
+    @Test
+    public void test3_2() throws Exception {
+        ObjectWriter<Bean3> objectWriter = ObjectWriters.of(
+                Bean3.class,
+                fieldWriter("names", TypeUtils.PARAM_TYPE_LIST_STR, List.class, Bean3::getNames)
+        );
+
+        Bean3 bean = new Bean3();
+        bean.names = new ArrayList<>();
+        bean.names.add("1");
+        bean.names.add("2");
+        JSONWriter jsonWriter = JSONWriter.of();
+        objectWriter.write(jsonWriter, bean);
+        assertEquals("{\"names\":[\"1\",\"2\"]}", jsonWriter.toString());
+    }
+
+    public static class Bean3 {
+        private List<String> names;
+
+        public List<String> getNames() {
+            return names;
+        }
+
+        public void setNames(List<String> names) {
+            this.names = names;
+        }
+    }
+
+    @Test
+    public void test4() throws Exception {
+        ObjectWriter<Bean4> objectWriter = ObjectWriters.of(
+                Bean4.class,
+                fieldWriterList("names", Long.class, Bean4::getNames)
+        );
+
+        Bean4 bean = new Bean4();
+        bean.names = new ArrayList<>();
+        bean.names.add(1L);
+        bean.names.add(2L);
+        JSONWriter jsonWriter = JSONWriter.of();
+        objectWriter.write(jsonWriter, bean);
+        assertEquals("{\"names\":[1,2]}", jsonWriter.toString());
+    }
+
+    public static class Bean4 {
+        private List<Long> names;
+
+        public List<Long> getNames() {
+            return names;
+        }
+
+        public void setNames(List<Long> names) {
+            this.names = names;
+        }
+    }
+
+    @Test
+    public void testFloat() throws Exception {
+        ObjectWriter<Bean5> objectWriter = ObjectWriters.of(
+                Bean5.class,
+                fieldWriter("value", Bean5::getValue)
+        );
+
+        Bean5 bean = new Bean5();
+        bean.value = 12.0F;
+        JSONWriter jsonWriter = JSONWriter.of();
+        objectWriter.write(jsonWriter, bean);
+        assertEquals("{\"value\":12.0}", jsonWriter.toString());
+    }
+
+    public static class Bean5 {
+        private Float value;
+
+        public Float getValue() {
+            return value;
+        }
+    }
+
+    @Test
+    public void testDouble() throws Exception {
+        ObjectWriter<Bean6> objectWriter = ObjectWriters.of(
+                Bean6.class,
+                fieldWriter("value", Bean6::getValue)
+        );
+
+        Bean6 bean = new Bean6();
+        bean.value = 12.0D;
+        JSONWriter jsonWriter = JSONWriter.of();
+        objectWriter.write(jsonWriter, bean);
+        assertEquals("{\"value\":12.0}", jsonWriter.toString());
+    }
+
+    public static class Bean6 {
+        private Double value;
+
+        public Double getValue() {
+            return value;
+        }
+    }
+
+    @Test
+    public void testBoolean() throws Exception {
+        ObjectWriter<Bean7> objectWriter = ObjectWriters.of(
+                Bean7.class,
+                fieldWriter("value", Bean7::getValue)
+        );
+
+        Bean7 bean = new Bean7();
+        bean.value = true;
+        JSONWriter jsonWriter = JSONWriter.of();
+        objectWriter.write(jsonWriter, bean);
+        assertEquals("{\"value\":true}", jsonWriter.toString());
+    }
+
+    @Test
+    public void testBoolean_1() throws Exception {
+        ObjectWriter<Bean7> objectWriter = ObjectWriters.objectWriter(
+                Bean7.class,
+                0,
+                fieldWriter("value", Bean7::getValue)
+        );
+
+        Bean7 bean = new Bean7();
+        bean.value = true;
+        JSONWriter jsonWriter = JSONWriter.of();
+        objectWriter.write(jsonWriter, bean);
+        assertEquals("{\"value\":true}", jsonWriter.toString());
+    }
+
+    public static class Bean7 {
+        private Boolean value;
+
+        public Boolean getValue() {
+            return value;
+        }
+    }
 }

example-graalvm-native/src/main/java/com/alibaba/fastjson2/example/graalvm_native/App.java

@@ -69,29 +69,29 @@ public class App {
     private static void registerReaderAndWriter() {
         JSON.register(MediaContent.class, ObjectWriters.objectWriter(
                 MediaContent.class,
-                ObjectWriters.fieldWriter("media", Media.class, (MediaContent e) -> e.getMedia()),
+                ObjectWriters.fieldWriter("media", Media.class, MediaContent::getMedia),
-                ObjectWriters.fieldWriterList("images", Image.class, (MediaContent e) -> e.getImages())
+                ObjectWriters.fieldWriterList("images", Image.class, MediaContent::getImages)
         ));
 
         JSON.register(MediaContent.class, ObjectReaders.of(
                 MediaContent::new,
-                fieldReader("media", Media.class, (MediaContent o, Media v) -> o.setMedia(v)),
+                fieldReader("media", Media.class, MediaContent::setMedia),
-                fieldReaderList("images", Image.class, ArrayList::new, (MediaContent o, List<Image> v) -> o.setImages(v))
+                fieldReaderList("images", Image.class, ArrayList::new, MediaContent::setImages)
         ));
 
         JSON.register(Media.class, ObjectWriters.objectWriter(
                 Media.class,
-                ObjectWriters.fieldWriter("bitrate", (Media e) -> e.getBitrate()),
+                ObjectWriters.fieldWriter("bitrate", Media::getBitrate),
-                ObjectWriters.fieldWriter("duration", (Media e) -> e.getDuration()),
+                ObjectWriters.fieldWriter("duration", Media::getDuration),
-                ObjectWriters.fieldWriter("format", (Media e) -> e.getFormat()),
+                ObjectWriters.fieldWriter("format", Media::getFormat),
-                ObjectWriters.fieldWriter("height", (Media e) -> e.getHeight()),
+                ObjectWriters.fieldWriter("height", Media::getHeight),
-                ObjectWriters.fieldWriterList("persons", String.class, (Media e) -> e.getPersons()),
+                ObjectWriters.fieldWriterList("persons", String.class, Media::getPersons),
-                ObjectWriters.fieldWriter("player", Player.class, (Media e) -> e.getPlayer()),
+                ObjectWriters.fieldWriter("player", Player.class, Media::getPlayer),
-                ObjectWriters.fieldWriter("size", (Media e) -> e.getSize()),
+                ObjectWriters.fieldWriter("size", Media::getSize),
-                ObjectWriters.fieldWriter("title", (Media e) -> e.getTitle()),
+                ObjectWriters.fieldWriter("title", Media::getTitle),
-                ObjectWriters.fieldWriter("uri", (Media e) -> e.getUri()),
+                ObjectWriters.fieldWriter("uri", Media::getUri),
-                ObjectWriters.fieldWriter("width", (Media e) -> e.getWidth()),
+                ObjectWriters.fieldWriter("width", Media::getWidth),
-                ObjectWriters.fieldWriter("copyright", (Media e) -> e.getCopyright())
+                ObjectWriters.fieldWriter("copyright", Media::getCopyright)
         ));
 
         JSON.register(Media.class, ObjectReaders.of(
@@ -100,8 +100,8 @@ public class App {
                 fieldReaderLong("duration", Media::setDuration),
                 fieldReaderString("format", Media::setFormat),
                 fieldReaderInt("height", Media::setHeight),
-                fieldReaderList("persons", String.class, ArrayList::new, (Media o, List<String> v) -> o.setPersons(v)),
+                fieldReaderList("persons", String.class, ArrayList::new, Media::setPersons),
-                fieldReader("player", Player.class, (Media o, Player v) -> o.setPlayer(v)),
+                fieldReader("player", Player.class, Media::setPlayer),
                 fieldReaderLong("size", Media::setSize),
                 fieldReaderString("title", Media::setTitle),
                 fieldReaderString("uri", Media::setUri),
@@ -112,7 +112,7 @@ public class App {
         JSON.register(Image.class, ObjectWriters.objectWriter(
                 Image.class,
                 ObjectWriters.fieldWriter("height", Image::getHeight),
-                ObjectWriters.fieldWriter("size", Size.class, (Image e) -> e.getSize()),
+                ObjectWriters.fieldWriter("size", Size.class, Image::getSize),
                 ObjectWriters.fieldWriter("title", Image::getTitle),
                 ObjectWriters.fieldWriter("uri", Image::getUri),
                 ObjectWriters.fieldWriter("width", Image::getWidth)
@@ -121,9 +121,9 @@ public class App {
         JSON.register(Image.class, ObjectReaders.of(
                 Image::new,
                 fieldReaderInt("height", Image::setHeight),
-                fieldReader("size", Size.class, (Image o, Size v) -> o.setSize(v)),
+                fieldReader("size", Size.class, Image::setSize),
-                fieldReader("title", String.class, (Image o, String v) -> o.setTitle(v)),
+                fieldReaderString("title", Image::setTitle),
-                fieldReader("uri", String.class, (Image o, String v) -> o.setUri(v)),
+                fieldReaderString("uri", Image::setUri),
                 fieldReaderInt("width", Image::setWidth)
         ));
     }