Add rate limiting code

implementations/java/rate_limiting/SlidingWindowLog.java

@@ -0,0 +1,33 @@
+package implementations.java.rate_limiting;
+
+import java.time.Instant;
+import java.util.LinkedList;
+import java.util.Queue;
+
+public class SlidingWindowLog {
+    private final long windowSizeInSeconds;   // Size of the sliding window in seconds
+    private final long maxRequestsPerWindow;  // Maximum number of requests allowed in the window
+    private final Queue<Long> requestLog;     // Log of request timestamps
+
+    public SlidingWindowLog(long windowSizeInSeconds, long maxRequestsPerWindow) {
+        this.windowSizeInSeconds = windowSizeInSeconds;
+        this.maxRequestsPerWindow = maxRequestsPerWindow;
+        this.requestLog = new LinkedList<>();
+    }
+
+    public synchronized boolean allowRequest() {
+        long now = Instant.now().getEpochSecond();
+        long windowStart = now - windowSizeInSeconds;
+
+        // Remove timestamps that are outside of the current window
+        while (!requestLog.isEmpty() && requestLog.peek() <= windowStart) {
+            requestLog.poll();
+        }
+
+        if (requestLog.size() < maxRequestsPerWindow) {
+            requestLog.offer(now);  // Log this request
+            return true;            // Allow the request
+        }
+        return false;  // We've exceeded the limit for this window, deny the request
+    }    
+}