Fixes the exponential backoff for small delay values

core/src/main/java/org/jclouds/http/handlers/BackoffLimitedRetryHandler.java

@@ -16,6 +16,7 @@
  */
 package org.jclouds.http.handlers;
 
+import static java.lang.Math.max;
 import static org.jclouds.http.HttpUtils.releasePayload;
 
 import java.io.IOException;
@@ -124,10 +125,16 @@ public class BackoffLimitedRetryHandler implements HttpRetryHandler, IOException
 
    public void imposeBackoffExponentialDelay(long period, long maxPeriod, int pow, int failureCount, int max,
             String commandDescription) {
+      if (period == 0) {
+         // Essentially disables the exponential backoff
+         logger.debug("Retry %d/%d: delaying for %d ms: %s", failureCount, max, 0, commandDescription);
+         return;
+      }
       long delayMs = (long) (period * Math.pow(failureCount, pow));
       // Add random delay to avoid thundering herd problem when multiple
       // simultaneous failed requests retry after sleeping for the same delay.
-      delayMs += new Random().nextInt((int) (delayMs / 10));
+      // Throws an exception for a value of 0
+      delayMs += new Random().nextInt((int) (max(delayMs / 10, 1) ));
       delayMs = delayMs > maxPeriod ? maxPeriod : delayMs;
       logger.debug("Retry %d/%d: delaying for %d ms: %s", failureCount, max, delayMs, commandDescription);
       try {
@@ -136,5 +143,4 @@ public class BackoffLimitedRetryHandler implements HttpRetryHandler, IOException
          Throwables.propagate(e);
       }
    }
-
 }

core/src/test/java/org/jclouds/http/handlers/BackoffLimitedRetryHandlerTest.java

@@ -80,6 +80,42 @@ public class BackoffLimitedRetryHandlerTest {
 
    }
 
+   @Test
+   void testExponentialBackoffDelaySmallInterval5() throws InterruptedException {
+      long period = 5;
+      long acceptableDelay = period - 1;
+
+      long startTime = System.nanoTime();
+      handler.imposeBackoffExponentialDelay(period, 2, 1, 5, "TEST FAILURE: 1");
+      long elapsedTime = (System.nanoTime() - startTime) / 1000000;
+      assert elapsedTime >= period - 1 : elapsedTime;
+      assertTrue(elapsedTime < period + acceptableDelay);
+   }
+
+   @Test
+   void testExponentialBackoffDelaySmallInterval1() throws InterruptedException {
+      long period = 1;
+      long acceptableDelay = 5;
+
+      long startTime = System.nanoTime();
+      handler.imposeBackoffExponentialDelay(period, 2, 1, 5, "TEST FAILURE: 1");
+      long elapsedTime = (System.nanoTime() - startTime) / 1000000;
+      assert elapsedTime >= period - 1 : elapsedTime;
+      assertTrue(elapsedTime < period + acceptableDelay);
+   }
+
+   @Test
+   void testExponentialBackoffDelaySmallInterval0() throws InterruptedException {
+      long period = 0;
+      long acceptableDelay = 5;
+
+      long startTime = System.nanoTime();
+      handler.imposeBackoffExponentialDelay(period, 2, 1, 5, "TEST FAILURE: 1");
+      long elapsedTime = (System.nanoTime() - startTime) / 1000000;
+      assert elapsedTime >= period - 1 : elapsedTime;
+      assertTrue(elapsedTime < period + acceptableDelay);
+   }
+
    @Test
    void testClosesInputStream() throws InterruptedException, IOException, SecurityException, NoSuchMethodException {
       HttpCommand command = createCommand();