Adding optional support for serialisation. (#346)

Adding optional support for serialisation.

Author: msailes

.github/workflows/aws-lambda-java-serialization.yml

@@ -24,10 +24,11 @@ jobs:
       uses: actions/setup-java@v1
       with:
         java-version: 1.8
-    
+
+    # Package target module
+    - name: Install serialization with Maven
+      run: mvn -B install --file aws-lambda-java-serialization/pom.xml
     # Install base module
     - name: Install events with Maven
       run: mvn -B install --file aws-lambda-java-events/pom.xml
-    # Package target module
-    - name: Package serialization with Maven
-      run: mvn -B package --file aws-lambda-java-serialization/pom.xml
+

aws-lambda-java-serialization/pom.xml

@@ -49,6 +49,11 @@
             <artifactId>jackson-datatype-jsr310</artifactId>
             <version>${jackson.jsr10.version}</version>
         </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.datatype</groupId>
+            <artifactId>jackson-datatype-jdk8</artifactId>
+            <version>${jackson.jsr10.version}</version>
+        </dependency>
         <dependency>
             <groupId>com.google.code.gson</groupId>
             <artifactId>gson</artifactId>

aws-lambda-java-serialization/src/main/java/com/amazonaws/services/lambda/serialization/JacksonPojoSerializer.java

@@ -2,28 +2,22 @@
 
 package com.amazonaws.services.lambda.serialization;
 
-import com.amazonaws.services.lambda.serialization.PojoSerializer;
-import com.amazonaws.services.lambda.serialization.CustomPojoSerializer;
 import com.fasterxml.jackson.core.JsonFactory;
 import com.fasterxml.jackson.core.JsonParser;
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.annotation.JsonInclude.Include;
 import com.fasterxml.jackson.core.json.JsonReadFeature;
 import com.fasterxml.jackson.core.json.JsonWriteFeature;
-import com.fasterxml.jackson.core.StreamWriteFeature;
-import com.fasterxml.jackson.core.StreamReadFeature;
 import com.fasterxml.jackson.databind.DeserializationConfig;
 import com.fasterxml.jackson.databind.DeserializationContext;
 import com.fasterxml.jackson.databind.DeserializationFeature;
-import com.fasterxml.jackson.databind.JavaType;
 import com.fasterxml.jackson.databind.JsonDeserializer;
 import com.fasterxml.jackson.databind.MapperFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
-import com.fasterxml.jackson.databind.ObjectReader;
-import com.fasterxml.jackson.databind.ObjectWriter;
 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 com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
 
 import java.io.IOException;
@@ -126,8 +120,8 @@ private static ObjectMapper createObjectMapper() {
         module.addDeserializer(Void.class, new VoidDeserializer());
         mapper.registerModule(module);
 
-        JavaTimeModule javaTimeModule = new JavaTimeModule();
-        mapper.registerModule(javaTimeModule);
+        mapper.registerModule(new JavaTimeModule());
+        mapper.registerModule(new Jdk8Module());
 
         return mapper;
     }

aws-lambda-java-serialization/src/test/java/com/amazonaws/services/lambda/serialization/JacksonPojoSerializerTest.java

@@ -1,16 +1,53 @@
 package com.amazonaws.services.lambda.serialization;
 
-import com.amazonaws.services.lambda.serialization.JacksonPojoSerializer;
-
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
 import org.junit.jupiter.api.Test;
-import org.junit.jupiter.api.Assertions;
+
+import java.util.Optional;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 public class JacksonPojoSerializerTest {
 
+    private static final ObjectMapper MAPPER = JacksonPojoSerializer.getInstance().getMapper();
+
     @Test
     public void deserializeVoidAsNonNull() throws Exception {
-        JacksonPojoSerializer instance = JacksonPojoSerializer.getInstance();
-        Void actual = instance.getMapper().readValue("{}", Void.class);
-        Assertions.assertNotNull(actual);
+        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;
+        }
     }
 }