Adding the Optional support to the JacksonFactory

aws-lambda-java-runtime-interface-client/src/test/java/com/amazonaws/services/lambda/runtime/serialization/factories/JacksonFactoryTest.java

@@ -2,17 +2,55 @@
 
 package com.amazonaws.services.lambda.runtime.serialization.factories;
 
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
 import org.junit.jupiter.api.Test;
 
+import java.util.Optional;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 public class JacksonFactoryTest {
 
+    private JacksonFactory jacksonFactory = JacksonFactory.getInstance();
+    private ObjectMapper mapper = jacksonFactory.getMapper();
+
     @Test
     public void deserializeVoidAsNonNull() throws Exception {
-        JacksonFactory instance = JacksonFactory.getInstance();
-        Void actual = instance.getMapper().readValue("{}", Void.class);
+        Void actual = mapper.readValue("{}", Void.class);
         assertNotNull(actual);
     }
 
+    @Test
+    public void testOptionalAsEmpty() throws JsonProcessingException {
+        Contact emptyEmail = new Contact("Example Co.", Optional.empty());
+        String emptyEmailJson = mapper.writeValueAsString(emptyEmail);
+        assertEquals("{\"name\":\"Example Co.\",\"email\":null}", emptyEmailJson);
+    }
+
+    @Test
+    public void testOptionalWithValue() throws JsonProcessingException {
+        Contact withEmail = new Contact("Example Co.", Optional.of("[email protected]"));
+        String withEmailJson = mapper.writeValueAsString(withEmail);
+        assertEquals("{\"name\":\"Example Co.\",\"email\":\"[email protected]\"}", withEmailJson);
+    }
+
+    static class Contact {
+        private final String name;
+        private final Optional<String> email;
+
+        public Contact(String name, Optional<String> email) {
+            this.name = name;
+            this.email = email;
+        }
+
+        public String getName() {
+            return name;
+        }
+
+        public Optional<String> getEmail() {
+            return email;
+        }
+    }
 }

aws-lambda-java-serialization/pom.xml

@@ -32,15 +32,22 @@
         <maven.compiler.source>1.8</maven.compiler.source>
         <maven.compiler.target>1.8</maven.compiler.target>
         <relocation.prefix>com.amazonaws.lambda.thirdparty</relocation.prefix>
+        <jackson.version>2.10.0</jackson.version>
     </properties>
 
     <!-- If you're adding a new dependency, make sure it and its dependencies are relocated in the shade stage below -->
     <dependencies>
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-databind</artifactId>
-            <version>2.10.0</version>
+            <version>${jackson.version}</version>
         </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.datatype</groupId>
+            <artifactId>jackson-datatype-jdk8</artifactId>
+            <version>${jackson.version}</version>
+        </dependency>
+
         <dependency>
             <groupId>com.google.code.gson</groupId>
             <artifactId>gson</artifactId>

aws-lambda-java-serialization/src/main/java/com/amazonaws/services/lambda/runtime/serialization/factories/JacksonFactory.java

@@ -20,6 +20,7 @@
 import com.fasterxml.jackson.databind.SerializationConfig;
 import com.fasterxml.jackson.databind.SerializationFeature;
 import com.fasterxml.jackson.databind.module.SimpleModule;
+import com.fasterxml.jackson.datatype.jdk8.Jdk8Module;
 
 import java.io.IOException;
 import java.io.OutputStream;
@@ -112,6 +113,7 @@ private static ObjectMapper createObjectMapper() {
         SimpleModule module = new SimpleModule();
         module.addDeserializer(Void.class, new VoidDeserializer());
         mapper.registerModule(module);
+        mapper.registerModule(new Jdk8Module());
 
         return mapper;
     }