NIFI-2754

- Migrating swap to active prior to swapping if necessary.
- This closes #1000.

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-framework-core/src/main/java/org/apache/nifi/controller/StandardFlowFileQueue.java

@@ -389,7 +389,8 @@ public class StandardFlowFileQueue implements FlowFileQueue {
             if (flowFile != null) {
                 incrementActiveQueueSize(-1, -flowFile.getSize());
             }
-        } while (isExpired);
+        }
+        while (isExpired);
 
         if (!expiredRecords.isEmpty()) {
             incrementActiveQueueSize(-expiredRecords.size(), -expiredBytes);
@@ -547,6 +548,8 @@ public class StandardFlowFileQueue implements FlowFileQueue {
             return;
         }
 
+        migrateSwapToActive();
+
         final int numSwapFiles = swapQueue.size() / SWAP_RECORD_POLL_SIZE;
 
         int originalSwapQueueCount = swapQueue.size();

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-framework-core/src/test/java/org/apache/nifi/controller/TestStandardFlowFileQueue.java

@@ -25,6 +25,7 @@ import static org.junit.Assert.assertTrue;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -503,6 +504,29 @@ public class TestStandardFlowFileQueue {
         assertNull(status.getFailureReason());
     }
 
+    @Test(timeout = 5000)
+    public void testListFlowFilesResultsLimitedCollection() throws InterruptedException {
+        Collection<FlowFileRecord> tff = new ArrayList<>();
+        //Swap Size is 10000 records, so 30000 is equal to 3 swap files.
+        for (int i = 0; i < 30000; i++) {
+            tff.add(new TestFlowFile());
+        }
+
+        queue.putAll(tff);
+
+        final ListFlowFileStatus status = queue.listFlowFiles(UUID.randomUUID().toString(), 100);
+        assertNotNull(status);
+        assertEquals(30000, status.getQueueSize().getObjectCount());
+
+        while (status.getState() != ListFlowFileState.COMPLETE) {
+            Thread.sleep(100);
+        }
+
+        assertEquals(100, status.getFlowFileSummaries().size());
+        assertEquals(100, status.getCompletionPercentage());
+        assertNull(status.getFailureReason());
+    }
+
 
     private class TestSwapManager implements FlowFileSwapManager {
         private final Map<String, List<FlowFileRecord>> swappedOut = new HashMap<>();