NIFI-2268: Instead of allowing HandleHttpRequest to run constantly calling BlockingQueue.poll() as fast as possible, call BlockingQueue.poll(2, TimeUnit.MILLISECONDS) to avoid overutilization of CPU when there is no work to be done

This closes #1762.

Signed-off-by: Bryan Bende <bbende@apache.org>

nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/main/java/org/apache/nifi/processors/standard/HandleHttpRequest.java

@@ -484,7 +484,14 @@ public class HandleHttpRequest extends AbstractProcessor {
             throw new ProcessException("Failed to initialize the server",e);
         }
 
-        final HttpRequestContainer container = containerQueue.poll();
+        HttpRequestContainer container;
+        try {
+            container = containerQueue.poll(2, TimeUnit.MILLISECONDS);
+        } catch (final InterruptedException e1) {
+            Thread.currentThread().interrupt();
+            return;
+        }
+
         if (container == null) {
             return;
         }