Implement WebClient and Aggregator

.gitignore

+target/
+.idea/
+*.iml
+logs/
+out/
\ No newline at end of file

httpclient/src/main/java/Aggregator.java

+import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.CompletableFuture;
 
@@ -11,17 +12,30 @@ public class Aggregator {
 
     /*send task to list of workers*/
     public List<String> sendTasksToWorkers(List<String> workersAddresses, List<String> tasks) {
-       /*
-       Add your code here
-        */
-        throw new UnsupportedOperationException();
+        return sendTasksToWorkers(workersAddresses, tasks, null);
     }
 
     /*send task to list of workers*/
     public List<String> sendTasksToWorkers(List<String> workersAddresses, List<String> tasks, String headers) {
-       /*
-       Add your code here
-        */
-        throw new UnsupportedOperationException();
+        if (workersAddresses.size() != tasks.size()) {
+            throw new IllegalArgumentException(
+                    "Number of workers (" + workersAddresses.size()
+                            + ") must equal number of tasks (" + tasks.size() + ")");
+        }
+
+        List<CompletableFuture<String>> futures = new ArrayList<>();
+        for (int i = 0; i < workersAddresses.size(); i++) {
+            byte[] payload = tasks.get(i).getBytes();
+            CompletableFuture<String> future = (headers == null)
+                    ? webClient.sendTask(workersAddresses.get(i), payload)
+                    : webClient.sendTask(workersAddresses.get(i), payload, headers);
+            futures.add(future);
+        }
+
+        List<String> results = new ArrayList<>();
+        for (CompletableFuture<String> future : futures) {
+            results.add(future.join());
+        }
+        return results;
     }
 }
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httpclient/src/main/java/WebClient.java

+import java.net.URI;
 import java.net.http.HttpClient;
-import java.util.ArrayList;
-import java.util.List;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
 import java.util.concurrent.CompletableFuture;
 
 public class WebClient {
@@ -15,17 +16,29 @@ public class WebClient {
 
     /* send task (post http request) asynchronously */
     public CompletableFuture<String> sendTask(String url, byte[] requestPayload) {
-    /*
-    Add your code here
-     */
-        throw new UnsupportedOperationException();
+        return sendTask(url, requestPayload, null);
     }
 
     /* send task (post http request) asynchronously with custom headers*/
     public CompletableFuture<String> sendTask(String url, byte[] requestPayload, String headers) {
-    /*
-    Add your code here
-     */
-        throw new UnsupportedOperationException();
+        HttpRequest.Builder builder = HttpRequest.newBuilder()
+                .uri(URI.create(url))
+                .POST(HttpRequest.BodyPublishers.ofByteArray(requestPayload));
+
+        if (headers != null && !headers.isBlank()) {
+            int idx = headers.indexOf(':');
+            if (idx <= 0) {
+                throw new IllegalArgumentException(
+                        "Invalid header format, expected 'Name: value' but got: " + headers);
+            }
+            String name = headers.substring(0, idx).trim();
+            String value = headers.substring(idx + 1).trim();
+            builder.header(name, value);
+        }
+
+        HttpRequest request = builder.build();
+
+        return client.sendAsync(request, HttpResponse.BodyHandlers.ofString())
+                .thenApply(HttpResponse::body);
     }
 }
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