Fixed the snipped and README. Removed possible NPE.

Added @throws docs.

gcloud-java-dns/README.md

@@ -300,22 +300,17 @@ while (recordIterator.hasNext()) {
 // Build and apply the change request to our zone if it contains records to delete
 ChangeRequestInfo changeRequest = changeBuilder.build();
 if (!changeRequest.deletions().isEmpty()) {
-  changeRequest = dns.applyChangeRequest(zoneName, changeRequest);
+  ChangeRequest pendingRequest = dns.applyChangeRequest(zoneName, changeRequest);
 
-  // Wait for change to finish, but save data traffic by transferring only ID and status
-  Dns.ChangeRequestOption option =
-      Dns.ChangeRequestOption.fields(Dns.ChangeRequestField.STATUS);
-  while (ChangeRequestInfo.Status.PENDING.equals(changeRequest.status())) {
+  // Wait for the change request to complete
+  while (!pendingRequest.isDone()) {
     System.out.println("Waiting for change to complete. Going to sleep for 500ms...");
     try {
       Thread.sleep(500);
     } catch (InterruptedException e) {
       System.err.println("The thread was interrupted while waiting for change request to be "
           + "processed.");
     }
-
-    // Update the change, but fetch only change ID and status
-    changeRequest = dns.getChangeRequest(zoneName, changeRequest.generatedId(), option);
   }
 }
 

gcloud-java-dns/src/main/java/com/google/gcloud/dns/ChangeRequest.java

@@ -162,25 +162,27 @@ public ChangeRequest applyTo(String zoneName, Dns.ChangeRequestOption... options
    * {@code options} will be {@code null} regardless of whether they are initialized or not in
    * {@code this} instance.
    *
-   * @return an object containing the updated information
+   * @return an object with the updated information or {@code null} if it does not exist
+   * @throws DnsException upon failure of the API call or if the associated zone was not found
    */
   public ChangeRequest reload(Dns.ChangeRequestOption... options) {
     return dns.getChangeRequest(zone, generatedId(), options);
   }
 
   /**
    * Returns {@code true} if the change request has been completed. The function makes an API call
-   * to Google Cloud DNS in order request the status update only if the status of the change request
-   * is {@link Status#PENDING}. If the status is already {@link Status#DONE}, the method returns
-   * {@code true} without an API call.
+   * to Google Cloud DNS in order to request the status update only if the status of the change
+   * request is {@link Status#PENDING}. If the status is already {@link Status#DONE}, the method
+   * returns {@code true} without an API call.
+   *
+   * @throws DnsException upon failure of the API call or if the associated zone was not found
    */
   public boolean isDone() {
     if (status() == Status.DONE) {
       return true;
     }
     ChangeRequest updated = reload(Dns.ChangeRequestOption.fields(Dns.ChangeRequestField.STATUS));
-    return updated.status() == Status.DONE;
-
+    return updated == null || updated.status() == Status.DONE;
   }
 
   @Override

gcloud-java-examples/src/main/java/com/google/gcloud/examples/dns/snippets/DeleteZone.java

@@ -22,6 +22,7 @@
 
 package com.google.gcloud.examples.dns.snippets;
 
+import com.google.gcloud.dns.ChangeRequest;
 import com.google.gcloud.dns.ChangeRequestInfo;
 import com.google.gcloud.dns.Dns;
 import com.google.gcloud.dns.DnsOptions;
@@ -59,21 +60,17 @@ public static void main(String... args) {
     // Build and apply the change request to our zone if it contains records to delete
     ChangeRequestInfo changeRequest = changeBuilder.build();
     if (!changeRequest.deletions().isEmpty()) {
-      changeRequest = dns.applyChangeRequest(zoneName, changeRequest);
+      ChangeRequest pendingRequest = dns.applyChangeRequest(zoneName, changeRequest);
 
-      // Wait for change to finish, but save data traffic by transferring only ID and status
-      Dns.ChangeRequestOption option =
-          Dns.ChangeRequestOption.fields(Dns.ChangeRequestField.STATUS);
-      while (ChangeRequestInfo.Status.PENDING.equals(changeRequest.status())) {
+      // Wait for the change request to complete
+      while (!pendingRequest.isDone()) {
         System.out.println("Waiting for change to complete. Going to sleep for 500ms...");
         try {
           Thread.sleep(500);
         } catch (InterruptedException e) {
           System.err.println("The thread was interrupted while waiting for change request to be "
               + "processed.");
         }
-        // Update the change, but fetch only change ID and status
-        changeRequest = dns.getChangeRequest(zoneName, changeRequest.generatedId(), option);
       }
     }
 

gcloud-java-examples/src/main/java/com/google/gcloud/examples/dns/snippets/ManipulateZonesAndRecordSets.java

@@ -128,22 +128,17 @@ public static void main(String... args) {
     // Build and apply the change request to our zone if it contains records to delete
     changeRequest = changeBuilder.build();
     if (!changeRequest.deletions().isEmpty()) {
-      changeRequest = dns.applyChangeRequest(zoneName, changeRequest);
+      ChangeRequest pendingRequest = dns.applyChangeRequest(zoneName, changeRequest);
 
-      // Wait for change to finish, but save data traffic by transferring only ID and status
-      Dns.ChangeRequestOption option =
-          Dns.ChangeRequestOption.fields(Dns.ChangeRequestField.STATUS);
-      while (ChangeRequest.Status.PENDING.equals(changeRequest.status())) {
+      // Wait for the change request to complete
+      while (!pendingRequest.isDone()) {
         System.out.println("Waiting for change to complete. Going to sleep for 500ms...");
         try {
           Thread.sleep(500);
         } catch (InterruptedException e) {
           System.err.println("The thread was interrupted while waiting for change request to be "
               + "processed.");
         }
-
-        // Update the change, but fetch only change ID and status
-        changeRequest = dns.getChangeRequest(zoneName, changeRequest.generatedId(), option);
       }
     }