Merge pull request #358 from marenzo/array_format_support

adding helper for serialization format of object mapper to be array

Author: xerial

msgpack-jackson/README.md

@@ -83,3 +83,15 @@ Java
   // xs => [zero, 1, 2.0, null]
 ```
 
+### Serialization format
+
+By default, the serialization format is object, which means it includes the schema of the serialized entity (POJO).
+To serialize an entity without the schema, only as array, you can add the annotation `@JsonFormat(shape=JsonFormat.Shape.ARRAY)` to the entity definition.
+Also, it's possible to set the serialization format for the object mapper instance to be array by changing the annotation inspector of object mapper to `JsonArrayFormat`:
+
+```
+  ObjectMapper objectMapper = new ObjectMapper(new MessagePackFactory());
+  objectMapper.setAnnotationIntrospector(new JsonArrayFormat());
+```
+
+This format provides compatibility with msgpack-java 0.6.x serialization api.

msgpack-jackson/src/main/java/org/msgpack/jackson/dataformat/JsonArrayFormat.java

@@ -0,0 +1,31 @@
+package org.msgpack.jackson.dataformat;
+
+import com.fasterxml.jackson.annotation.JsonFormat;
+import com.fasterxml.jackson.databind.introspect.Annotated;
+import com.fasterxml.jackson.databind.introspect.JacksonAnnotationIntrospector;
+
+import static com.fasterxml.jackson.annotation.JsonFormat.Shape.ARRAY;
+
+/**
+ * Provides the ability of serializing POJOs without their schema.
+ * Similar to @JsonFormat annotation with JsonFormat.Shape.ARRAY, but in a programmatic
+ * way.
+ *
+ * This also provides same behavior as msgpack-java 0.6.x serialization api.
+ */
+public class JsonArrayFormat extends JacksonAnnotationIntrospector
+{
+  private static final JsonFormat.Value ARRAY_FORMAT = new JsonFormat.Value().withShape(ARRAY);
+
+  @Override
+  public JsonFormat.Value findFormat(Annotated ann)
+  {
+    // If the entity contains JsonFormat annotation, give it higher priority.
+    JsonFormat.Value precedenceFormat = super.findFormat(ann);
+    if (precedenceFormat != null) {
+      return precedenceFormat;
+    }
+
+    return ARRAY_FORMAT;
+  }
+}

msgpack-jackson/src/test/java/org/msgpack/jackson/dataformat/MessagePackDataformatForPojoTest.java

@@ -15,13 +15,18 @@
 //
 package org.msgpack.jackson.dataformat;
 
+import com.fasterxml.jackson.databind.ObjectMapper;
 import org.junit.Test;
 
 import java.io.IOException;
-import java.util.Arrays;
+import java.nio.charset.Charset;
+
+import static org.hamcrest.CoreMatchers.not;
+import static org.hamcrest.CoreMatchers.containsString;
 
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.assertThat;
+import static org.junit.Assert.assertArrayEquals;
 
 public class MessagePackDataformatForPojoTest
         extends MessagePackDataformatTestBase
@@ -38,7 +43,7 @@ public void testNormal()
         assertEquals(normalPojo.l, value.l);
         assertEquals(normalPojo.f, value.f, 0.000001f);
         assertEquals(normalPojo.d, value.d, 0.000001f);
-        assertTrue(Arrays.equals(normalPojo.b, value.b));
+        assertArrayEquals(normalPojo.b, value.b);
         assertEquals(normalPojo.bi, value.bi);
         assertEquals(normalPojo.suit, Suit.HEART);
     }
@@ -50,7 +55,7 @@ public void testNestedList()
         byte[] bytes = objectMapper.writeValueAsBytes(nestedListPojo);
         NestedListPojo value = objectMapper.readValue(bytes, NestedListPojo.class);
         assertEquals(nestedListPojo.s, value.s);
-        assertTrue(Arrays.equals(nestedListPojo.strs.toArray(), value.strs.toArray()));
+        assertArrayEquals(nestedListPojo.strs.toArray(), value.strs.toArray());
     }
 
     @Test
@@ -99,4 +104,20 @@ public void testChangingPropertyNames()
         ChangingPropertyNamesPojo value = objectMapper.readValue(bytes, ChangingPropertyNamesPojo.class);
         assertEquals("komamitsu", value.getTheName());
     }
+
+    @Test
+    public void testSerializationWithoutSchema()
+            throws IOException
+    {
+        ObjectMapper objectMapper = new ObjectMapper(factory); // to not affect shared objectMapper state
+        objectMapper.setAnnotationIntrospector(new JsonArrayFormat());
+        byte[] bytes = objectMapper.writeValueAsBytes(complexPojo);
+        String scheme = new String(bytes, Charset.forName("UTF-8"));
+        assertThat(scheme, not(containsString("name"))); // validating schema doesn't contains keys, that's just array
+        ComplexPojo value = objectMapper.readValue(bytes, ComplexPojo.class);
+        assertEquals("komamitsu", value.name);
+        assertEquals(20, value.age);
+        assertArrayEquals(complexPojo.values.toArray(), value.values.toArray());
+        assertEquals(complexPojo.grades.get("math"), value.grades.get("math"));
+    }
 }

msgpack-jackson/src/test/java/org/msgpack/jackson/dataformat/MessagePackDataformatTestBase.java

@@ -32,6 +32,8 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Map;
+import java.util.Collections;
 
 public class MessagePackDataformatTestBase
 {
@@ -43,6 +45,7 @@ public class MessagePackDataformatTestBase
     protected NestedListPojo nestedListPojo;
     protected NestedListComplexPojo nestedListComplexPojo;
     protected TinyPojo tinyPojo;
+    protected ComplexPojo complexPojo;
 
     @Before
     public void setup()
@@ -65,14 +68,21 @@ public void setup()
 
         nestedListPojo = new NestedListPojo();
         nestedListPojo.s = "a string";
-        nestedListPojo.strs = Arrays.asList(new String[] {"string", "another string", "another string"});
+        nestedListPojo.strs = Arrays.asList("string", "another string", "another string");
 
         tinyPojo = new TinyPojo();
         tinyPojo.t = "t string";
+
         nestedListComplexPojo = new NestedListComplexPojo();
         nestedListComplexPojo.s = "a string";
         nestedListComplexPojo.foos = new ArrayList<TinyPojo>();
         nestedListComplexPojo.foos.add(tinyPojo);
+
+        complexPojo = new ComplexPojo();
+        complexPojo.name = "komamitsu";
+        complexPojo.age = 20;
+        complexPojo.grades = Collections.singletonMap("math", 97);
+        complexPojo.values = Arrays.asList("one", "two", "three");
     }
 
     @After
@@ -108,6 +118,14 @@ public static class NestedListPojo
         public List<String> strs;
     }
 
+    public static class ComplexPojo
+    {
+        public String name;
+        public int age;
+        public List<String> values;
+        public Map<String, Integer> grades;
+    }
+
     public static class TinyPojo
     {
         public String t;