Update HandlerStream code to show deserialization of custom Record object

Code courtesy of @msailes , thanks!

Author: yualexan

.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+    "java.configuration.updateBuildConfiguration": "interactive"
+}

sample-apps/java-basic/build.gradle

@@ -9,6 +9,7 @@ repositories {
 dependencies {
     implementation 'com.amazonaws:aws-lambda-java-core:1.2.1'
     implementation 'org.slf4j:slf4j-nop:2.0.6'
+    implementation 'com.fasterxml.jackson.core:jackson-databind:2.17.0'
     testImplementation 'org.junit.jupiter:junit-jupiter-api:5.8.2'
     testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.8.2'
 }
@@ -26,8 +27,9 @@ task buildZip(type: Zip) {
 }
 
 java {
-    sourceCompatibility = JavaVersion.VERSION_11
-    targetCompatibility = JavaVersion.VERSION_11
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(21)
+    }
 }
 
 build.dependsOn buildZip

sample-apps/java-basic/pom.xml

@@ -8,8 +8,10 @@
   <name>java-basic-function</name>
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <maven.compiler.source>11</maven.compiler.source>
-    <maven.compiler.target>11</maven.compiler.target>
+    <java.version>21</java.version>
+    <maven.compiler.source>${java.version}</maven.compiler.source>
+    <maven.compiler.target>${java.version}</maven.compiler.target>
+    <maven.compiler.release>${java.version}</maven.compiler.release>
   </properties>
   <dependencies>
     <dependency>
@@ -22,6 +24,11 @@
       <artifactId>slf4j-nop</artifactId>
       <version>2.0.6</version>
     </dependency>
+    <dependency>
+      <groupId>com.fasterxml.jackson.core</groupId>
+      <artifactId>jackson-databind</artifactId>
+      <version>2.17.0</version>
+  </dependency>
     <dependency>
       <groupId>org.junit.jupiter</groupId>
       <artifactId>junit-jupiter-api</artifactId>

sample-apps/java-basic/src/main/java/example/HandlerStream.java

@@ -1,44 +1,39 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: MIT-0
+
 package example;
 
 import com.amazonaws.services.lambda.runtime.Context;
-import com.amazonaws.services.lambda.runtime.LambdaLogger;
 import com.amazonaws.services.lambda.runtime.RequestStreamHandler;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.databind.ObjectMapper;
 
-import java.io.InputStream;
-import java.io.InputStreamReader;
-import java.io.BufferedReader;
-import java.io.BufferedWriter;
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.OutputStream;
-import java.io.OutputStreamWriter;
-import java.io.PrintWriter;
-import java.nio.charset.Charset;
+import java.util.List;
 
-// Handler value: example.HandlerStream
 public class HandlerStream implements RequestStreamHandler {
 
-  @Override
-  /*
-   * Takes an InputStream and an OutputStream. Reads from the InputStream,
-   * and copies all characters to the OutputStream.
-   */
-  public void handleRequest(InputStream inputStream, OutputStream outputStream, Context context) throws IOException
-  {
-    LambdaLogger logger = context.getLogger();
-    BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, Charset.forName("US-ASCII")));
-    PrintWriter writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream, Charset.forName("US-ASCII"))));
-    int nextChar;
-    try {
-      while ((nextChar = reader.read()) != -1) {
-        outputStream.write(nextChar);
-      }
-    } catch (IOException e) {
-      e.printStackTrace();
-    } finally {
-      reader.close();
-      String finalString = writer.toString();
-      logger.log("Final string result: " + finalString);
-      writer.close();
+    private static final ObjectMapper objectMapper = new ObjectMapper();
+
+    @Override
+    public void handleRequest(InputStream input, OutputStream output, Context context) throws IOException {
+        Order order = objectMapper.readValue(input, Order.class);
+
+        processOrder(order);
+        OrderAccepted orderAccepted = new OrderAccepted(order.orderId);
+
+        objectMapper.writeValue(output, orderAccepted);
     }
-  }
+
+    private void processOrder(Order order) {
+        // business logic
+    }
+
+    public record Order(@JsonProperty("orderId") String orderId, @JsonProperty("items") List<Item> items) { }
+
+    public record Item(@JsonProperty("name") String name, @JsonProperty("quantity") Integer quantity) { }
+
+    public record OrderAccepted(@JsonProperty("orderId") String orderId) { }
 }

sample-apps/java-basic/src/test/java/example/InvokeTest.java

@@ -1,6 +1,5 @@
 package example;
 
-import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
@@ -14,6 +13,7 @@
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.io.OutputStream;
 import java.nio.charset.StandardCharsets;
 import java.util.HashMap;
 import java.util.List;
@@ -58,20 +58,27 @@ void testHandlerList() {
   }
 
   @Test
-  void testHandlerStream() throws IOException {
-    logger.info("Invoke TEST - HandlerStream");
-    String inputStr = "Hello world";
-    byte[] inputBytes = inputStr.getBytes();
-    ByteArrayInputStream inputStream = new ByteArrayInputStream(inputBytes);
-    ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
-    Context context = new TestContext();
-    HandlerStream handler = new HandlerStream();
-    handler.handleRequest(inputStream, outputStream, context);
-    byte[] outputBytes = outputStream.toByteArray();
-    assertArrayEquals(inputBytes, outputBytes);
-    String outputStr = new String(outputBytes, StandardCharsets.UTF_8);
-    assertEquals(inputStr, outputStr);
-  }
+    public void testHandlerStream() throws IOException {
+        HandlerStream orderProcessor = new HandlerStream();
+        String input = """
+                {
+                    "orderId": "123",
+                    "items": [
+                        {
+                            "name": "widgets",
+                            "quantity": 10
+                        }
+                    ]
+                }
+                """;
+        Context context = null;
+        ByteArrayInputStream inputStream = new ByteArrayInputStream(input.getBytes(StandardCharsets.UTF_8));
+        OutputStream outputStream = new ByteArrayOutputStream();
+
+        orderProcessor.handleRequest(inputStream, outputStream, context);
+
+        assertEquals("{\"orderId\":\"123\"}", outputStream.toString());
+    }
 
   @Test
   void testHandlerString() {

sample-apps/java-basic/template-mvn.yml

@@ -7,7 +7,7 @@ Resources:
     Properties:
       CodeUri: target/java-basic-1.0-SNAPSHOT.jar
       Handler: example.Handler
-      Runtime: java11
+      Runtime: java21
       Description: Java function
       MemorySize: 2048
       Timeout: 10

sample-apps/java-basic/template.yml

@@ -7,7 +7,7 @@ Resources:
     Properties:
       CodeUri: build/distributions/java-basic.zip
       Handler: example.Handler
-      Runtime: java11
+      Runtime: java21
       Description: Java function
       MemorySize: 2048
       Timeout: 10