From c06fabf99466dfee6f001c660702fe5b4cefdccc Mon Sep 17 00:00:00 2001
From: Ben Makusha <btmakusha@duck.com>
Date: Mon, 17 Nov 2025 22:12:00 -0500
Subject: [PATCH] chore: [UPDATE] Request Executor implementation <> failed to
 code the solution in interview

---
 .../java/interview/wise/RequestExecutor.java  | 123 ++++++++++++++++++
 1 file changed, 123 insertions(+)
 create mode 100644 src/main/java/interview/wise/RequestExecutor.java

diff --git a/src/main/java/interview/wise/RequestExecutor.java b/src/main/java/interview/wise/RequestExecutor.java
new file mode 100644
index 0000000..60f8304
--- /dev/null
+++ b/src/main/java/interview/wise/RequestExecutor.java
@@ -0,0 +1,123 @@
+package interview.wise;
+
+import java.time.Clock;
+import java.time.ZoneId;
+import java.util.*;
+
+/** WISE Interview Question || This is a classic Circuit Breaker / Rate Limiter pattern!
+ * 
+ * You are given a RequestExecutor class that executes requests to various services.
+ *
+ * public Response execute(Request request) {
+ *     // perform your error tracking here
+ *     return request.call();
+ * }
+ *
+ * with the following helper method for tracking timestamps of service s coming in:
+ *
+ * public int getCurrentTimeInMins() {
+ *     return Clock.getCurrentTimeStamp(); // this method returns the integer value that the request came in.
+ *     For example, if request came in at 12:04 pm, it returns 4
+ * }
+ * There are two objects in relation to this problem:
+ *
+ * class Request {
+ *     String name;
+ *     Response response;
+ *     public Response call() {
+ *         return response;
+ *     }
+ * }
+ *
+ *
+ * class Response {
+ *     int status;
+ *     String message;
+ * }
+ *
+ * Example Walkthrough:
+ * ServiceA   -->    Status 200 ("Success")
+ * ServiceB   -->    Status 500 ("Failed")         // first failure
+ * ServiceB   -->   Status 500 ("Failed")       // second failure
+ * ServiceB   -->    Status 500 ("Failed").     // third failure
+ * ServiceB  --->    ("Blocked - [service has hit threshold limit within allotted time]")
+ * ... wait 10 mins...
+ * ServiceC   -->   Status 200 ("Success")
+ * ServiceB  -->    Status 200 ("Success")
+ */
+public class RequestExecutor {
+    private class ServiceState {
+        List<Integer> failureTimestamps = new ArrayList<>();
+        Integer blockedAt = null;
+    }
+
+    public class Response {
+        int status;
+        String message;
+    }
+
+    public class Request {
+        String name;
+        Response response;
+
+        public Response call() {
+            return response;
+        }
+    }
+
+    private static final int FAILURE_THRESHOLD = 3;
+    private static final int FAILURE_WINDOW_MINS = 10;
+    private static final int BLOCK_DURATION_MINS = 5;
+
+    private Map<String, ServiceState> serviceStates = new HashMap<>();
+
+    public Response execute(Request request) {
+        String serviceName = request.name;
+        int currentTime = getCurrentTimeInMinutes();
+
+        serviceStates.putIfAbsent(serviceName, new ServiceState());
+        ServiceState state = serviceStates.get(serviceName);
+
+        if (state.blockedAt != null) {
+            if (currentTime - state.blockedAt < BLOCK_DURATION_MINS) {
+                Response blockedResponse = new Response();
+                blockedResponse.status = 429; // Too Many Requests
+                blockedResponse.message = "Blocked - service has hit threshold limit within alloted time frame.";
+                return blockedResponse;
+            } else {
+                state.blockedAt = null; // Unblock the service
+                state.failureTimestamps.clear();
+            }
+        }
+
+        // Execute the actual request
+        Response response = request.call();
+
+        if (response.status != 200) {
+            // track current failure
+            state.failureTimestamps.add(currentTime);
+
+            if (state.failureTimestamps.size() >= FAILURE_THRESHOLD) {
+                // Get the timestamp of the 3rd most recent failure
+                int thirdMostRecnt = state.failureTimestamps.get(
+                        state.failureTimestamps.size() - FAILURE_THRESHOLD
+                );
+
+                if (currentTime - thirdMostRecnt <= FAILURE_WINDOW_MINS)
+                    state.blockedAt = currentTime;
+            }
+
+            while (!state.failureTimestamps.isEmpty() &&
+                    currentTime - state.failureTimestamps.get(0) > FAILURE_WINDOW_MINS) {
+                state.failureTimestamps.remove(0);
+            }
+        }
+
+        return response;
+    }
+
+    private int getCurrentTimeInMinutes() {
+        return Math.toIntExact(Clock.tickMinutes(ZoneId.of("UTC")).instant().getEpochSecond() / 60);
+        //return (int) (System.currentTimeMillis() / 60000);
+    }
+}