public static OperationFuture recursiveDelete()

in twill-zookeeper/src/main/java/org/apache/twill/zookeeper/ZKOperations.java [221:282]
45 lines of code
6 McCabe index (conditional complexity)

  public static OperationFuture<String> recursiveDelete(final ZKClient zkClient, final String path) {
    final SettableOperationFuture<String> resultFuture =
      SettableOperationFuture.create(path, Threads.SAME_THREAD_EXECUTOR);

    // Try to delete the given path.
    Futures.addCallback(zkClient.delete(path), new FutureCallback<String>() {
      private final FutureCallback<String> deleteCallback = this;

      @Override
      public void onSuccess(String result) {
        // Path deleted successfully. Operation done.
        resultFuture.set(result);
      }

      @Override
      public void onFailure(Throwable t) {
        // Failed to delete the given path
        if (!(t instanceof KeeperException.NotEmptyException || t instanceof KeeperException.NoNodeException)) {
          // For errors other than NotEmptyException, treat the operation as failed.
          resultFuture.setException(t);
          return;
        }

        // If failed because of NotEmptyException, get the list of children under the given path
        Futures.addCallback(zkClient.getChildren(path), new FutureCallback<NodeChildren>() {

          @Override
          public void onSuccess(NodeChildren result) {
            // Delete all children nodes recursively.
            final List<OperationFuture<String>> deleteFutures = Lists.newLinkedList();
            for (String child :result.getChildren()) {
              deleteFutures.add(recursiveDelete(zkClient, path + "/" + child));
            }

            // When deletion of all children succeeded, delete the given path again.
            Futures.successfulAsList(deleteFutures).addListener(new Runnable() {
              @Override
              public void run() {
                for (OperationFuture<String> deleteFuture : deleteFutures) {
                  try {
                    // If any exception when deleting children, treat the operation as failed.
                    deleteFuture.get();
                  } catch (Exception e) {
                    resultFuture.setException(e.getCause());
                  }
                }
                Futures.addCallback(zkClient.delete(path), deleteCallback, Threads.SAME_THREAD_EXECUTOR);
              }
            }, Threads.SAME_THREAD_EXECUTOR);
          }

          @Override
          public void onFailure(Throwable t) {
            // If failed to get list of children, treat the operation as failed.
            resultFuture.setException(t);
          }
        }, Threads.SAME_THREAD_EXECUTOR);
      }
    }, Threads.SAME_THREAD_EXECUTOR);

    return resultFuture;
  }