From 6dd9ba49492189ad37065da35786ebfff1f02301 Mon Sep 17 00:00:00 2001
From: Clebert Suconic <clebertsuconic@apache.org>
Date: Thu, 9 Mar 2017 22:34:56 -0500
Subject: [PATCH] ARTEMIS-1029 Cleaning up small possible Exception

treating an exception after the PagingIterator in case of duplicates cleanups
---
 .../management/impl/QueueControlImpl.java     | 41 +++++++++++++------
 .../core/server/impl/ScaleDownHandler.java    |  6 ++-
 2 files changed, 33 insertions(+), 14 deletions(-)

diff --git a/artemis-server/src/main/java/org/apache/activemq/artemis/core/management/impl/QueueControlImpl.java b/artemis-server/src/main/java/org/apache/activemq/artemis/core/management/impl/QueueControlImpl.java
index 5ecea64e5a0..c5f21114220 100644
--- a/artemis-server/src/main/java/org/apache/activemq/artemis/core/management/impl/QueueControlImpl.java
+++ b/artemis-server/src/main/java/org/apache/activemq/artemis/core/management/impl/QueueControlImpl.java
@@ -29,6 +29,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.NoSuchElementException;
 
 import org.apache.activemq.artemis.api.core.ActiveMQException;
 import org.apache.activemq.artemis.api.core.JsonUtil;
@@ -434,12 +435,16 @@ public Map<String, Object>[] listMessages(final String filterStr) throws Excepti
          List<Map<String, Object>> messages = new ArrayList<>();
          queue.flushExecutor();
          try (LinkedListIterator<MessageReference> iterator = queue.browserIterator()) {
-            while (iterator.hasNext()) {
-               MessageReference ref = iterator.next();
-               if (filter == null || filter.match(ref.getMessage())) {
-                  Message message = ref.getMessage();
-                  messages.add(message.toMap());
+            try {
+               while (iterator.hasNext()) {
+                  MessageReference ref = iterator.next();
+                  if (filter == null || filter.match(ref.getMessage())) {
+                     Message message = ref.getMessage();
+                     messages.add(message.toMap());
+                  }
                }
+            } catch (NoSuchElementException ignored) {
+               // this could happen through paging browsing
             }
             return messages.toArray(new Map[messages.size()]);
          }
@@ -524,11 +529,16 @@ public long countMessages(final String filterStr) throws Exception {
          } else {
             try (LinkedListIterator<MessageReference> iterator = queue.browserIterator()) {
                int count = 0;
-               while (iterator.hasNext()) {
-                  MessageReference ref = iterator.next();
-                  if (filter.match(ref.getMessage())) {
-                     count++;
+
+               try {
+                  while (iterator.hasNext()) {
+                     MessageReference ref = iterator.next();
+                     if (filter.match(ref.getMessage())) {
+                        count++;
+                     }
                   }
+               } catch (NoSuchElementException ignored) {
+                  // this could happen through paging browsing
                }
                return count;
             }
@@ -928,13 +938,18 @@ public CompositeData[] browse(String filter) throws Exception {
          Filter thefilter = FilterImpl.createFilter(filter);
          queue.flushExecutor();
          try (LinkedListIterator<MessageReference> iterator = queue.browserIterator()) {
-            while (iterator.hasNext() && currentPageSize++ < pageSize) {
-               MessageReference ref = iterator.next();
-               if (thefilter == null || thefilter.match(ref.getMessage())) {
-                  c.add(OpenTypeSupport.convert(ref));
+            try {
+               while (iterator.hasNext() && currentPageSize++ < pageSize) {
+                  MessageReference ref = iterator.next();
+                  if (thefilter == null || thefilter.match(ref.getMessage())) {
+                     c.add(OpenTypeSupport.convert(ref));
 
+                  }
                }
+            } catch (NoSuchElementException ignored) {
+               // this could happen through paging browsing
             }
+
             CompositeData[] rc = new CompositeData[c.size()];
             c.toArray(rc);
             return rc;
diff --git a/artemis-server/src/main/java/org/apache/activemq/artemis/core/server/impl/ScaleDownHandler.java b/artemis-server/src/main/java/org/apache/activemq/artemis/core/server/impl/ScaleDownHandler.java
index 4590c0bd861..bf0ed0bc406 100644
--- a/artemis-server/src/main/java/org/apache/activemq/artemis/core/server/impl/ScaleDownHandler.java
+++ b/artemis-server/src/main/java/org/apache/activemq/artemis/core/server/impl/ScaleDownHandler.java
@@ -25,6 +25,7 @@
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.NoSuchElementException;
 import java.util.Set;
 import java.util.TreeSet;
 
@@ -210,8 +211,9 @@ public long scaleDownRegularMessages(final SimpleString address,
                   for (QueuesXRefInnerManager queueFound : queuesFound) {
                      ackMessageOnQueue(tx, queueFound.getQueue(), messageReference);
                   }
-
                }
+            } catch (NoSuchElementException ignored) {
+               // this could happen through paging browsing
             }
          }
 
@@ -294,6 +296,8 @@ private long scaleDownSNF(final SimpleString address,
 
                ackMessageOnQueue(tx, queue, messageRef);
             }
+         } catch (NoSuchElementException ignored) {
+            // this could happen through paging browsing
          }
       }