SOLR-7285: ActionThrottle will not pause if getNanoTime first returns 0.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1668370 13f79535-47bb-0310-9956-ffa450edef68

solr/core/src/java/org/apache/solr/cloud/ActionThrottle.java

@@ -26,25 +26,45 @@ import org.slf4j.LoggerFactory;
 public class ActionThrottle {
   private static Logger log = LoggerFactory.getLogger(ActionThrottle.class);
   
-  private volatile long lastActionStartedAt;
+  private volatile Long lastActionStartedAt;
-  private volatile long minMsBetweenActions;
+  private volatile Long minMsBetweenActions;
 
   private final String name;
 
+  private final NanoTimeSource nanoTimeSource;
+  
+  public interface NanoTimeSource {
+    long getTime();
+  }
+  
+  private static class DefaultNanoTimeSource implements NanoTimeSource {
+    @Override
+    public long getTime() {
+      return System.nanoTime();
+    }
+  }
+  
   public ActionThrottle(String name, long minMsBetweenActions) {
     this.name = name;
     this.minMsBetweenActions = minMsBetweenActions;
+    this.nanoTimeSource = new DefaultNanoTimeSource();
+  }
+  
+  public ActionThrottle(String name, long minMsBetweenActions, NanoTimeSource nanoTimeSource) {
+    this.name = name;
+    this.minMsBetweenActions = minMsBetweenActions;
+    this.nanoTimeSource = nanoTimeSource;
   }
   
   public void markAttemptingAction() {
-    lastActionStartedAt = System.nanoTime();
+    lastActionStartedAt = nanoTimeSource.getTime();
   }
   
   public void minimumWaitBetweenActions() {
-    if (lastActionStartedAt == 0) {
+    if (lastActionStartedAt == null) {
       return;
     }
-    long diff = System.nanoTime() - lastActionStartedAt;
+    long diff = nanoTimeSource.getTime() - lastActionStartedAt;
     int diffMs = (int) TimeUnit.MILLISECONDS.convert(diff, TimeUnit.NANOSECONDS);
     long minNsBetweenActions = TimeUnit.NANOSECONDS.convert(minMsBetweenActions, TimeUnit.MILLISECONDS);
     log.info("The last {} attempt started {}ms ago.", name, diffMs);
@@ -53,7 +73,7 @@ public class ActionThrottle {
     if (diffMs > 0 && diff < minNsBetweenActions) {
       sleep = (int) TimeUnit.MILLISECONDS.convert(minNsBetweenActions - diff, TimeUnit.NANOSECONDS);
     } else if (diffMs == 0) {
-      sleep = (int) minMsBetweenActions;
+      sleep = minMsBetweenActions.intValue();
     }
     
     if (sleep > 0) {

solr/core/src/test/org/apache/solr/cloud/ActionThrottleTest.java

@@ -17,9 +17,12 @@ package org.apache.solr.cloud;
  * limitations under the License.
  */
 
+import java.util.Arrays;
+import java.util.List;
 import java.util.concurrent.TimeUnit;
 
 import org.apache.solr.SolrTestCaseJ4;
+import org.apache.solr.cloud.ActionThrottle.NanoTimeSource;
 import org.junit.Test;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -27,6 +30,21 @@ import org.slf4j.LoggerFactory;
 public class ActionThrottleTest extends SolrTestCaseJ4 {
   protected static Logger log = LoggerFactory.getLogger(ActionThrottleTest.class);
   
+  static class TestNanoTimeSource implements NanoTimeSource {
+    
+    private List<Long> returnValues;
+    private int index = 0;
+
+    public TestNanoTimeSource(List<Long> returnValues) {
+      this.returnValues = returnValues;
+    }
+
+    @Override
+    public long getTime() {
+      return returnValues.get(index++);
+    }
+    
+  }
   
   @Test
   public void testBasics() throws Exception {
@@ -60,4 +78,20 @@ public class ActionThrottleTest extends SolrTestCaseJ4 {
     assertTrue(elaspsedTime + "ms", elaspsedTime >= 995);
   }
   
+  @Test
+  public void testAZeroNanoTimeReturnInWait() throws Exception {
+
+    ActionThrottle at = new ActionThrottle("test", 1000, new TestNanoTimeSource(Arrays.asList(new Long[]{0L, 10L})));
+    long start = System.nanoTime();
+    
+    at.markAttemptingAction();
+    
+    at.minimumWaitBetweenActions();
+    
+    long elaspsedTime = TimeUnit.MILLISECONDS.convert(System.nanoTime() - start, TimeUnit.NANOSECONDS);
+    
+    assertTrue(elaspsedTime + "ms", elaspsedTime >= 995);
+
+  }
+
 }