public Optional<ContainerPlacementRequestMessage> readContainerPlacementRequestMessage(UUID uuid) {
    Preconditions.checkState(!stopped, "Underlying metadata store not available");
    Preconditions.checkNotNull(uuid, "uuid cannot be null");

    byte[] messageBytes = containerPlacementMessageStore.get(
        toContainerPlacementMessageKey(uuid, ContainerPlacementRequestMessage.class));
    if (ArrayUtils.isNotEmpty(messageBytes)) {
      try {
        ContainerPlacementRequestMessage requestMessage =
            (ContainerPlacementRequestMessage) objectMapper.readValue(messageBytes, ContainerPlacementMessage.class);
        return Optional.of(requestMessage);
      } catch (IOException e) {
        throw new SamzaException(
            String.format("Error reading the ContainerPlacementResponseMessage for uuid: %s", uuid), e);
      }
    }
    return Optional.empty();
  }
Reads a {@link ContainerPlacementRequestMessage} from the underlying metastore
@param uuid uuid of the request
@return ContainerPlacementRequestMessage if present
samza-core/src/main/java/org/apache/samza/clustermanager/container/placement/ContainerPlacementMetadataStore.java