Make FilteredIterator::hasNext idempotent

Unidata · May 2, 2023 · e61f325 · e61f325
1 parent 98258e9
commit e61f325
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Showing 2 changed files with 20 additions and 2 deletions.
diff --git a/cdm/s3/src/main/java/thredds/filesystem/s3/ControllerS3.java b/cdm/s3/src/main/java/thredds/filesystem/s3/ControllerS3.java
@@ -141,24 +141,27 @@ private static class FilteredIterator implements Iterator<MFile> {
       this.mc = mc;
       this.wantDirs = wantDirs;
       this.fullInventory = false;
+      this.next = nextFilteredFile();
     }
 
     FilteredIterator(CollectionConfig mc, Iterator<MFile> iter, boolean wantDirs, boolean fullInventory) {
       this.orgIter = iter;
       this.mc = mc;
       this.wantDirs = wantDirs;
       this.fullInventory = fullInventory;
+      this.next = nextFilteredFile();
     }
 
     public boolean hasNext() {
-      next = nextFilteredFile();
       return (next != null);
     }
 
     public MFile next() {
       if (next == null)
         throw new NoSuchElementException();
-      return next;
+      final MFile mFile = next;
+      next = nextFilteredFile();
+      return mFile;
     }
 
     public void remove() {

diff --git a/cdm/s3/src/test/java/thredds/filesystem/s3/TestControllerS3.java b/cdm/s3/src/test/java/thredds/filesystem/s3/TestControllerS3.java
@@ -64,6 +64,21 @@ public static void setup() {
 
   }
 
+  @Test
+  public void shouldReturnSameValueFromHasNext() throws URISyntaxException {
+    final CdmS3Uri uri = new CdmS3Uri("cdms3:thredds-test-data");
+    final MFileFilter filter = new WildcardMatchOnName("testData.nc");
+    final CollectionConfig collectionConfig = new CollectionConfig(uri.getBucket(), uri.toString(), true, filter, null);
+    final ControllerS3 controller = new ControllerS3();
+    final Iterator<MFile> iterator = controller.getInventoryTop(collectionConfig, false);
+
+    assertThat(iterator.hasNext()).isTrue();
+    assertThat(iterator.hasNext()).isTrue();
+    iterator.next();
+    assertThat(iterator.hasNext()).isFalse();
+    assertThat(iterator.hasNext()).isFalse();
+  }
+
   //////////////////////
   // getInventoryTop() tests
   //