code: @Override
      public Map<String, String> getContentProperties(String spaceID,
                                                      String contentID,
                                                      String storeID)
          throws ResourceException {
          try {
              StorageProvider storage =
                  storageProviderFactory.getStorageProvider(storeID);
              return storage.getContentProperties(spaceID, contentID);
          } catch (NotFoundException e) {
              throw new ResourceNotFoundException("get properties for content",
                                                  spaceID,
                                                  contentID,
                                                  e);
          } catch (Exception e) {
              storageProviderFactory.expireStorageProvider(storeID);
              throw new ResourceException("get properties for content",
                                          spaceID,
                                          contentID,
                                          e);
          }
      }
docs: Retrieves the properties of a piece of content.
  
  @param spaceID
  @param contentID
  @return Map of content properties