public interface ViewOperations
Modifier and Type | Method and Description |
---|---|
void |
commit(ViewMetadata base,
ViewMetadata metadata)
Replace the base view metadata with a new version.
|
ViewMetadata |
current()
Return the currently loaded view metadata, without checking for updates.
|
ViewMetadata |
refresh()
Return the current view metadata after checking for updates.
|
ViewMetadata current()
ViewMetadata refresh()
void commit(ViewMetadata base, ViewMetadata metadata)
This method should implement and document atomicity guarantees.
Implementations must check that the base metadata is current to avoid overwriting updates. Once the atomic commit operation succeeds, implementations must not perform any operations that may fail because failure in this method cannot be distinguished from commit failure.
Implementations should throw a CommitStateUnknownException
in cases where it cannot be
determined if the commit succeeded or failed. For example if a network partition causes the
confirmation of the commit to be lost, the implementation should throw a
CommitStateUnknownException. An unknown state indicates to downstream users of this API that it
is not safe to perform clean up and remove any files. In general, strict metadata cleanup will
only trigger cleanups when the commit fails with an exception implementing the marker interface
CleanableFailure
. All other exceptions will be treated as
if the commit has failed.
base
- view metadata on which changes were basedmetadata
- new view metadata with updates