Add Java wrapper for AWS Lambda benchmarks

Author: mahlashrifi

benchmarks/wrappers/aws/java/Handler.java

@@ -0,0 +1,75 @@
+import com.amazonaws.services.lambda.runtime.Context;
+import com.amazonaws.services.lambda.runtime.RequestHandler;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.core.type.TypeReference;
+
+import faas.App;
+
+import java.io.File;
+import java.io.IOException;
+import java.time.Instant;
+import java.util.HashMap;
+import java.util.Map;
+
+public class Handler implements RequestHandler<Map<String, Object>, String> {
+    private static final ObjectMapper mapper = new ObjectMapper();
+
+    @Override
+    public String handleRequest(Map<String, Object> event, Context context) {
+
+        Map<String, Object> inputData = event;
+
+        // Extract input if trigger is API Gateway (body is a string)
+        if (event.containsKey("body") && event.get("body") instanceof String)
+            try {
+                inputData = mapper.readValue((String) event.get("body"),new TypeReference<Map<String, Object>>() {});
+            } catch (IOException e) {
+                throw new RuntimeException("Failed to parse JSON body", e);
+            }
+
+        App function = new App();
+
+        Instant begin = Instant.now();
+        long start_nano = System.nanoTime();
+
+        Map<String, Object> functionOutput = function.handler(inputData);
+
+        long end_nano = System.nanoTime();
+        Instant end = Instant.now();
+
+        
+        long computeTime = end_nano - start_nano;
+        // Detect cold start
+        boolean isCold = false;
+        String fileName = "/tmp/cold_run"; 
+
+        File file = new File(fileName);
+        if (!file.exists()) {
+            isCold = true;
+            try {
+                file.createNewFile();
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        }
+
+        // Convert to Unix timestamp in seconds.microseconds
+        String formattedBegin = String.format("%d.%06d", begin.getEpochSecond(), begin.getNano() / 1000); // Convert nanoseconds to microseconds
+        String formattedEnd = String.format("%d.%06d", end.getEpochSecond(), end.getNano() / 1000);
+
+ 
+        Map<String, Object> result = new HashMap<>();
+        result.put("begin", formattedBegin); 
+        result.put("end", formattedEnd);
+        result.put("request_id", context.getAwsRequestId());  
+        result.put("compute_time", computeTime);
+        result.put("is_cold", isCold);
+        result.put("result", functionOutput);
+        try {
+            return mapper.writeValueAsString(result);
+        } catch (IOException e) {
+            throw new RuntimeException("Failed to serialize result of benchmark to JSON in Wrapper", e);
+        }
+
+    }
+}