/**
* Get the ETag of the stream associated with the entity specified.
*
* @param object $entity The entity instance
* (media resource) associated
* with the stream for which
* the etag is to be obtained.
* @param ResourceStreamInfo $resourceStreamInfo This will be null if
* media resource is MLE,
* if media resource is named
* stream then will be the
* ResourceStreamInfo
* instance holding the
* details of named stream.
*
* @throws InvalidOperationException
* @return String Etag
*/
public function getStreamETag($entity, $resourceStreamInfo)
{
$eTag = null;
$this->_saveContentTypeAndETag();
if (is_null($resourceStreamInfo)) {
$this->_loadAndValidateStreamProvider();
$eTag = $this->_streamProvider->getStreamETag($entity, $this->_service->getOperationContext());
} else {
$this->_loadAndValidateStreamProvider2();
$eTag = $this->_streamProvider->getStreamETag2($entity, $resourceStreamInfo, $this->_service->getOperationContext());
}
$this->_verifyContentTypeOrETagModified('IDSSP::getStreamETag');
if (!self::isETagValueValid($eTag, true)) {
throw new InvalidOperationException(Messages::streamProviderWrapperGetStreamETagReturnedInvalidETagFormat());
}
return $eTag;
}
