msgpack · komamitsu · Sep 14, 2022 · Sep 13, 2022 · Sep 13, 2022 · Sep 13, 2022
diff --git a/msgpack-jackson/README.md b/msgpack-jackson/README.md
@@ -240,9 +240,27 @@ When you want to use non-String value as a key of Map, use `MessagePackKeySerial
  System.out.println(mapper.readValue(converted, Pojo.class));   // => Pojo{value=1234567890.98765432100}
 ```

+### Serialize and deserialize Instant instances as MessagePack extension type
+
+`timestamp` extension type is defined in MessagePack as type:-1. Registering `TimestampExtensionModule.INSTANCE` module enables automatic serialization and deserialization of java.time.Instant to/from the MessagePack extension type.
+
+```java
+    ObjectMapper objectMapper = new ObjectMapper(new MessagePackFactory())
+                                    .registerModule(TimestampExtensionModule.INSTANCE);
+    Pojo pojo = new Pojo();
+    // The type of `timestamp` variable is Instant
+    pojo.timestamp = Instant.now();
+    byte[] bytes = objectMapper.writeValueAsBytes(pojo);
+
+    // The Instant instance is serialized as MessagePack extension type (type: -1)
+
+    Pojo deserialized = objectMapper.readValue(bytes, Pojo.class);
+    System.out.println(deserialized);   // "2022-09-14T08:47:24.922Z"
+```
+
 ### Deserialize extension types with ExtensionTypeCustomDeserializers

-`ExtensionTypeCustomDeserializers` helps you to deserialize extension types easily.
+`ExtensionTypeCustomDeserializers` helps you to deserialize your own custom extension types easily.

 #### Deserialize extension type value directly


diff --git a/msgpack-jackson/src/main/java/org/msgpack/jackson/dataformat/TimestampExtensionModule.java b/msgpack-jackson/src/main/java/org/msgpack/jackson/dataformat/TimestampExtensionModule.java
@@ -0,0 +1,82 @@
+package org.msgpack.jackson.dataformat;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.databind.DeserializationContext;
+import com.fasterxml.jackson.databind.SerializerProvider;
+import com.fasterxml.jackson.databind.deser.std.StdDeserializer;
+import com.fasterxml.jackson.databind.module.SimpleModule;
+import com.fasterxml.jackson.databind.ser.std.StdSerializer;
+import org.msgpack.core.ExtensionTypeHeader;
+import org.msgpack.core.MessagePack;
+import org.msgpack.core.MessagePacker;
+import org.msgpack.core.MessageUnpacker;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.time.Instant;
+
+public class TimestampExtensionModule
+{
+    public static final byte EXT_TYPE = -1;
+    public static final SimpleModule INSTANCE = new SimpleModule("msgpack-ext-timestamp");
+
+    static {
+        INSTANCE.addSerializer(Instant.class, new InstantSerializer(Instant.class));
+        INSTANCE.addDeserializer(Instant.class, new InstantDeserializer(Instant.class));
+    }
+
+    private static class InstantSerializer extends StdSerializer<Instant>
+    {
+        protected InstantSerializer(Class<Instant> t)
+        {
+            super(t);
+        }
+
+        @Override
+        public void serialize(Instant value, JsonGenerator gen, SerializerProvider provider)
+            throws IOException
+        {
+            ByteArrayOutputStream os = new ByteArrayOutputStream();
+            // MEMO: Reusing these MessagePacker and MessageUnpacker instances would improve the performance
+            try (MessagePacker packer = MessagePack.newDefaultPacker(os)) {
+                packer.packTimestamp(value);
+            }
+            try (MessageUnpacker unpacker = MessagePack.newDefaultUnpacker(os.toByteArray())) {
+                ExtensionTypeHeader header = unpacker.unpackExtensionTypeHeader();
+                byte[] bytes = unpacker.readPayload(header.getLength());
+
+                MessagePackExtensionType extensionType = new MessagePackExtensionType(EXT_TYPE, bytes);
+                gen.writeObject(extensionType);
+            }
+        }
+    }
+
+    private static class InstantDeserializer extends StdDeserializer<Instant>
+    {
+        protected InstantDeserializer(Class<?> vc)
+        {
+            super(vc);
+        }
+
+        @Override
+        public Instant deserialize(JsonParser p, DeserializationContext ctxt)
+            throws IOException
+        {
+            MessagePackExtensionType ext = p.readValueAs(MessagePackExtensionType.class);
+            if (ext.getType() != EXT_TYPE) {
+                throw new RuntimeException(
+                        String.format("Unexpected extension type (0x%X) for Instant object", ext.getType()));
+            }
+
+            // MEMO: Reusing this MessageUnpacker instance would improve the performance
+            try (MessageUnpacker unpacker = MessagePack.newDefaultUnpacker(ext.getData())) {
+                return unpacker.unpackTimestamp(new ExtensionTypeHeader(EXT_TYPE, ext.getData().length));
+            }
+        }
+    }
+
+    private TimestampExtensionModule()
+    {
+    }
+}
diff --git a/...ck-jackson/src/test/java/org/msgpack/jackson/dataformat/TimestampExtensionModuleTest.java b/...ck-jackson/src/test/java/org/msgpack/jackson/dataformat/TimestampExtensionModuleTest.java
@@ -0,0 +1,218 @@
+//
+// MessagePack for Java
+//
+//    Licensed under the Apache License, Version 2.0 (the "License");
+//    you may not use this file except in compliance with the License.
+//    You may obtain a copy of the License at
+//
+//        http://www.apache.org/licenses/LICENSE-2.0
+//
+//    Unless required by applicable law or agreed to in writing, software
+//    distributed under the License is distributed on an "AS IS" BASIS,
+//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//    See the License for the specific language governing permissions and
+//    limitations under the License.
+//
+package org.msgpack.jackson.dataformat;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.junit.Before;
+import org.junit.Test;
+import org.msgpack.core.MessagePack;
+import org.msgpack.core.MessagePacker;
+import org.msgpack.core.MessageUnpacker;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.time.Instant;
+
+import static org.junit.Assert.assertEquals;
+
+public class TimestampExtensionModuleTest
+{
+    private final ObjectMapper objectMapper = new ObjectMapper(new MessagePackFactory());
+    private final SingleInstant singleInstant = new SingleInstant();
+    private final TripleInstants tripleInstants = new TripleInstants();
+
+    private static class SingleInstant
+    {
+        public Instant instant;
+    }
+
+    private static class TripleInstants
+    {
+        public Instant a;
+        public Instant b;
+        public Instant c;
+    }
+
+    @Before
+    public void setUp()
+            throws Exception
+    {
+        objectMapper.registerModule(TimestampExtensionModule.INSTANCE);
+    }
+
+    @Test
+    public void testSingleInstantPojo()
+            throws IOException
+    {
+        singleInstant.instant = Instant.now();
+        byte[] bytes = objectMapper.writeValueAsBytes(singleInstant);
+        SingleInstant deserialized = objectMapper.readValue(bytes, SingleInstant.class);
+        assertEquals(singleInstant.instant, deserialized.instant);
+    }
+
+    @Test
+    public void testTripleInstantsPojo()
+            throws IOException
+    {
+        Instant now = Instant.now();
+        tripleInstants.a = now.minusSeconds(1);
+        tripleInstants.b = now;
+        tripleInstants.c = now.plusSeconds(1);
+        byte[] bytes = objectMapper.writeValueAsBytes(tripleInstants);
+        TripleInstants deserialized = objectMapper.readValue(bytes, TripleInstants.class);
+        assertEquals(now.minusSeconds(1), deserialized.a);
+        assertEquals(now, deserialized.b);
+        assertEquals(now.plusSeconds(1), deserialized.c);
+    }
+
+    @Test
+    public void serialize32BitFormat()
+            throws IOException
+    {
+        singleInstant.instant = Instant.ofEpochSecond(Instant.now().getEpochSecond());
+
+        byte[] bytes = objectMapper.writeValueAsBytes(singleInstant);
+
+        // Check the size of serialized data first
+        try (MessageUnpacker unpacker = MessagePack.newDefaultUnpacker(bytes)) {
+            unpacker.unpackMapHeader();
+            assertEquals("instant", unpacker.unpackString());
+            assertEquals(4, unpacker.unpackExtensionTypeHeader().getLength());
+        }
+
+        try (MessageUnpacker unpacker = MessagePack.newDefaultUnpacker(bytes)) {
+            unpacker.unpackMapHeader();
+            unpacker.unpackString();
+            assertEquals(singleInstant.instant, unpacker.unpackTimestamp());
+        }
+    }
+
+    @Test
+    public void serialize64BitFormat()
+            throws IOException
+    {
+        singleInstant.instant = Instant.ofEpochSecond(Instant.now().getEpochSecond(), 1234);
+
+        byte[] bytes = objectMapper.writeValueAsBytes(singleInstant);
+
+        // Check the size of serialized data first
+        try (MessageUnpacker unpacker = MessagePack.newDefaultUnpacker(bytes)) {
+            unpacker.unpackMapHeader();
+            assertEquals("instant", unpacker.unpackString());
+            assertEquals(8, unpacker.unpackExtensionTypeHeader().getLength());
+        }
+
+        try (MessageUnpacker unpacker = MessagePack.newDefaultUnpacker(bytes)) {
+            unpacker.unpackMapHeader();
+            unpacker.unpackString();
+            assertEquals(singleInstant.instant, unpacker.unpackTimestamp());
+        }
+    }
+
+    @Test
+    public void serialize96BitFormat()
+            throws IOException
+    {
+        singleInstant.instant = Instant.ofEpochSecond(19880866800L /* 2600-01-01 */, 1234);
+
+        byte[] bytes = objectMapper.writeValueAsBytes(singleInstant);
+
+        // Check the size of serialized data first
+        try (MessageUnpacker unpacker = MessagePack.newDefaultUnpacker(bytes)) {
+            unpacker.unpackMapHeader();
+            assertEquals("instant", unpacker.unpackString());
+            assertEquals(12, unpacker.unpackExtensionTypeHeader().getLength());
+        }
+
+        try (MessageUnpacker unpacker = MessagePack.newDefaultUnpacker(bytes)) {
+            unpacker.unpackMapHeader();
+            unpacker.unpackString();
+            assertEquals(singleInstant.instant, unpacker.unpackTimestamp());
+        }
+    }
+
+    @Test
+    public void deserialize32BitFormat()
+            throws IOException
+    {
+        Instant instant = Instant.ofEpochSecond(Instant.now().getEpochSecond());
+
+        ByteArrayOutputStream os = new ByteArrayOutputStream();
+        try (MessagePacker packer = MessagePack.newDefaultPacker(os)) {
+            packer.packMapHeader(1)
+                    .packString("instant")
+                    .packTimestamp(instant);
+        }
+
+        byte[] bytes = os.toByteArray();
+        try (MessageUnpacker unpacker = MessagePack.newDefaultUnpacker(bytes)) {
+            unpacker.unpackMapHeader();
+            unpacker.unpackString();
+            assertEquals(4, unpacker.unpackExtensionTypeHeader().getLength());
+        }
+
+        SingleInstant deserialized = objectMapper.readValue(bytes, SingleInstant.class);
+        assertEquals(instant, deserialized.instant);
+    }
+
+    @Test
+    public void deserialize64BitFormat()
+            throws IOException
+    {
+        Instant instant = Instant.ofEpochSecond(Instant.now().getEpochSecond(), 1234);
+
+        ByteArrayOutputStream os = new ByteArrayOutputStream();
+        try (MessagePacker packer = MessagePack.newDefaultPacker(os)) {
+            packer.packMapHeader(1)
+                    .packString("instant")
+                    .packTimestamp(instant);
+        }
+
+        byte[] bytes = os.toByteArray();
+        try (MessageUnpacker unpacker = MessagePack.newDefaultUnpacker(bytes)) {
+            unpacker.unpackMapHeader();
+            unpacker.unpackString();
+            assertEquals(8, unpacker.unpackExtensionTypeHeader().getLength());
+        }
+
+        SingleInstant deserialized = objectMapper.readValue(bytes, SingleInstant.class);
+        assertEquals(instant, deserialized.instant);
+    }
+
+    @Test
+    public void deserialize96BitFormat()
+            throws IOException
+    {
+        Instant instant = Instant.ofEpochSecond(19880866800L /* 2600-01-01 */, 1234);
+
+        ByteArrayOutputStream os = new ByteArrayOutputStream();
+        try (MessagePacker packer = MessagePack.newDefaultPacker(os)) {
+            packer.packMapHeader(1)
+                    .packString("instant")
+                    .packTimestamp(instant);
+        }
+
+        byte[] bytes = os.toByteArray();
+        try (MessageUnpacker unpacker = MessagePack.newDefaultUnpacker(bytes)) {
+            unpacker.unpackMapHeader();
+            unpacker.unpackString();
+            assertEquals(12, unpacker.unpackExtensionTypeHeader().getLength());
+        }
+
+        SingleInstant deserialized = objectMapper.readValue(bytes, SingleInstant.class);
+        assertEquals(instant, deserialized.instant);
+    }
+}