Updated README to include Java

Author: katiewest820

README.md

@@ -31,6 +31,12 @@ cd nodejs;
 cd ..
 ```
 
+```
+cd java;
+./publish-layers.sh
+cd ..
+```
+
 ## Attaching Custom Lambda Layer ARNs
 
 The layers published to your account may be used directly within SAM, Cloudformation Templates, Serverless.yml, or other configuration methods that allow specifying the use of layers by ARN.
@@ -56,6 +62,9 @@ These steps will help you configure the layers correctly:
 3. Update your functions handler to point to the newly attached layer in the console for your function:
   * Python: newrelic_lambda_wrapper.handler
   * Node: newrelic-lambda-wrapper.handler
+  * Java:
+    * RequestHandler implementation: com.newrelic.java.HandlerWrapper::handleRequest
+    * RequestStreamHandlerWrapper implementation: RequestHandler implementation: com.newrelic.java.HandlerWrapper::handleStreamsRequest
 4. Add these environment variables to your Lambda console:
   * NEW_RELIC_ACCOUNT_ID: Your New Relic account ID
   * NEW_RELIC_LAMBDA_HANDLER: Path to your initial handler.

java/src/main/java/com/newrelic/java/RequestHandlerWrapper.java renamed to java/src/main/java/com/newrelic/java/HandlerWrapper.java

@@ -2,12 +2,19 @@
 
 import com.amazonaws.services.lambda.runtime.Context;
 import com.amazonaws.services.lambda.runtime.RequestHandler;
+import com.amazonaws.services.lambda.runtime.RequestStreamHandler;
 import com.newrelic.opentracing.LambdaTracer;
 import com.newrelic.opentracing.aws.LambdaTracing;
+import com.newrelic.opentracing.aws.StreamLambdaTracing;
 import io.opentracing.Tracer;
 import io.opentracing.util.GlobalTracer;
 
-public class RequestHandlerWrapper implements RequestHandler<Object, Object> {
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+public class HandlerWrapper {
+
     static JavaClassLoader javaClassLoader;
     static {
         // Obtain an instance of the OpenTracing Tracer of your choice
@@ -21,19 +28,26 @@ public class RequestHandlerWrapper implements RequestHandler<Object, Object> {
         String handlerMethod = parts.length == 2 ? parts[1] : "handleRequest";
 
         try {
-             javaClassLoader = JavaClassLoader.initializeClassLoader(handlerClass, handlerMethod);
+            javaClassLoader = JavaClassLoader.initializeClass(handlerClass, handlerMethod);
         } catch (ReflectiveOperationException e) {
             throw new RuntimeException("Error occurred during initialization of javaClassLoader: " + e);
         }
     }
 
-    // Instrumentation for RequestHandler
-    @Override
     public Object handleRequest(Object input, Context context) {
         return LambdaTracing.instrument(
                 input,
                 context,
                 (event, ctx) -> javaClassLoader.invokeClassMethod(input, context)
         );
     }
+
+    public void handleStreamsRequest(InputStream input, OutputStream output, Context context) throws IOException {
+        StreamLambdaTracing.instrument(
+                input,
+                output,
+                context,
+                javaClassLoader.getClassInstance()
+        );
+    }
 }

java/src/main/java/com/newrelic/java/JavaClassLoader.java

@@ -1,6 +1,7 @@
 package com.newrelic.java;
 
 import com.amazonaws.services.lambda.runtime.Context;
+import com.amazonaws.services.lambda.runtime.RequestHandler;
 import com.amazonaws.services.lambda.runtime.RequestStreamHandler;
 import com.amazonaws.services.lambda.runtime.serialization.PojoSerializer;
 import com.amazonaws.services.lambda.runtime.serialization.events.LambdaEventSerializers;
@@ -29,14 +30,21 @@ public class JavaClassLoader {
     private static MethodHandle methodHandle;
     private static RequestStreamHandler classInstance;
 
+    static JavaClassLoader initializeClass(String className, String methodName) throws ReflectiveOperationException {
+        Class loadedClass = classLoader.loadClass(className);
+        if (RequestStreamHandler.class.isAssignableFrom(loadedClass)) {
+            return initializeRequestStreamHandler(className, loadedClass);
+        }
+        return initializeRequestHandler(className, methodName, loadedClass);
+    }
+
     // RequestStreamHandler implementation constructor
     private JavaClassLoader(RequestStreamHandler classInstance) {
         this.classInstance = classInstance;
     }
 
     // RequestStreamHandler initializeClassLoader
-    static JavaClassLoader initializeClassLoader(String className) throws ReflectiveOperationException {
-        Class loadedClass = classLoader.loadClass(className);
+    static JavaClassLoader initializeRequestStreamHandler(String className, Class loadedClass) throws ReflectiveOperationException {
         RequestStreamHandler classInstance = (RequestStreamHandler) loadedClass.getDeclaredConstructor().newInstance();
         return new JavaClassLoader(classInstance);
     }
@@ -52,8 +60,7 @@ private JavaClassLoader(Class inputType, MethodHandle methodHandle) {
     }
 
     // RequestHandler initializeClassLoader
-    static JavaClassLoader initializeClassLoader(String className, String methodName) throws ReflectiveOperationException {
-        Class loadedClass = classLoader.loadClass(className);
+    static JavaClassLoader initializeRequestHandler(String className, String methodName, Class loadedClass) throws ReflectiveOperationException {
         Class methodInputType = null;
         for (Method method : loadedClass.getMethods()) {
             if (isUserHandlerMethod(method, className, methodName) == true) {