Demonstrate how to write a single iterator which calls jclouds BlobStore.list until it lists all blobs.

gistfile1.java

public class PageSetIterableTest {
   private class PageSetIterable implements Iterator<StorageMetadata> {
      private final String container;
      private ListContainerOptions options;
      private PageSet<? extends StorageMetadata> set;
      private Iterator<? extends StorageMetadata> iterator;

      private PageSetIterable(String container, ListContainerOptions options) {
         this.container = checkNotNull(container);
         advanceList(options);
      }

      @Override
      public boolean hasNext() {
         if (iterator.hasNext()) {
            return true;
         }
         String marker = set.getNextMarker();
         if (marker == null) {
            return false;
         }
         advanceList(options.afterMarker(marker));
         return iterator.hasNext();
      }

      @Override
      public StorageMetadata next() {
         if (hasNext()) {
            return iterator.next();
         } else {
            throw new NoSuchElementException();
         }
      }

      @Override
      public void remove() {
         throw new UnsupportedOperationException();
      }

      private void advanceList(ListContainerOptions options) {
         this.options = options;
         this.set = list(container, options);
         this.iterator = set.iterator();
      }
   }

   public static Iterator<? extends StorageMetadata> listAll(String container, ListContainerOptions options) {
      return new PageSetIterable(container, options);
   }
}