code: protected Set<String> getPermissionStrings(CustomData customData) {
          return new CustomDataPermissionsEditor(customData)
                  .setFieldName(getCustomDataFieldName())
                  .getPermissionStrings();
      }
docs: Returns a {@code Set&lt;String&gt;} of permission strings that are stored in the specified
  {@link CustomData} instance (under the {@link #getCustomDataFieldName() customDataFieldName} key), or an
  empty collection if no permissions are stored.
  <p/>
  This implementation internally delegates field access and Set construction to a
  {@link CustomDataPermissionsEditor} instance, e.g.
  <pre>
  return new CustomDataPermissionsEditor(customData)
  .setFieldName(getCustomDataFieldName())
  .getPermissionStrings();
  </pre>
  
  @param customData the custom data instance that might have a {@code Set&lt;String&gt;} of permissions stored in
  a key named {@link #getCustomDataFieldName()}.
  @return a {@code Set&lt;String&gt;} of permission strings that are stored in the specified
  {@link CustomData} instance (under the {@link #getCustomDataFieldName() customDataFieldName} key), or an
  empty collection if no permissions are stored.
  @see CustomDataPermissionsEditor