From 23d98684e460cca2ce1ca474b965af7592db3e9d Mon Sep 17 00:00:00 2001
From: Martin Derka <derka@google.com>
Date: Fri, 4 Mar 2016 09:41:11 -0800
Subject: [PATCH] Added pool of executors instead of spawning one threads.

---
 .../gcloud/dns/testing/LocalDnsHelper.java    | 24 +++++++++----------
 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/gcloud-java-dns/src/main/java/com/google/gcloud/dns/testing/LocalDnsHelper.java b/gcloud-java-dns/src/main/java/com/google/gcloud/dns/testing/LocalDnsHelper.java
index 984d58ef496b..cafbf764db69 100644
--- a/gcloud-java-dns/src/main/java/com/google/gcloud/dns/testing/LocalDnsHelper.java
+++ b/gcloud-java-dns/src/main/java/com/google/gcloud/dns/testing/LocalDnsHelper.java
@@ -69,6 +69,9 @@
 import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.ConcurrentNavigableMap;
 import java.util.concurrent.ConcurrentSkipListMap;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -106,8 +109,11 @@ public class LocalDnsHelper {
   private static final TreeSet<String> FORBIDDEN = Sets.newTreeSet(
       ImmutableList.of("google.com.", "com.", "example.com.", "net.", "org."));
   private static final Pattern ZONE_NAME_RE = Pattern.compile("[a-z][a-z0-9-]*");
+  private static final ScheduledExecutorService EXECUTORS =
+      Executors.newScheduledThreadPool(4, Executors.defaultThreadFactory());
 
   static {
+
     try {
       BASE_CONTEXT = new URI(CONTEXT);
     } catch (URISyntaxException e) {
@@ -741,28 +747,20 @@ Response createChange(String projectId, String zoneName, Change change, String..
   }
 
   /**
-   * Applies change. Uses a new thread which applies the change only if DELAY_CHANGE is > 0.
+   * Applies change. Uses a different pooled thread which applies the change only if {@code
+   * delayChange} is > 0.
    */
-  private Thread invokeChange(final String projectId, final String zoneName,
+  private void invokeChange(final String projectId, final String zoneName,
       final String changeId) {
     if (delayChange > 0) {
-      Thread thread = new Thread() {
+      EXECUTORS.schedule(new Runnable() {
         @Override
         public void run() {
-          try {
-            Thread.sleep(delayChange); // simulate delayed execution
-          } catch (InterruptedException ex) {
-            log.log(Level.WARNING, "Thread was interrupted while sleeping.", ex);
-          }
-          // start applying the changes
           applyExistingChange(projectId, zoneName, changeId);
         }
-      };
-      thread.start();
-      return thread;
+      }, delayChange, TimeUnit.MILLISECONDS);
     } else {
       applyExistingChange(projectId, zoneName, changeId);
-      return null;
     }
   }