tagObject Clean-up on Unexpected Failure

[doulikecookiedough]

If tagObject fails to tag a pid with a cid, we should try to remove orphaned files and revert any changes. Currently, only specific scenarios of whether reference files exist or not are accounted for.

[doulikecookiedough]

To make this process transparent, we will refactor tagObject by having it only synchronize the tagging process. When it is safe to proceed with tagging, we will call a new protected method: storeHashStoreRefs. This method will absorb the main functionality of tagObject.

Should any exception be raised, tagObject will have a new protected method to call: unTagObject. This will revert the process (remove the pid & then attempt to delete the cid refs file, and then delete the pid refs file).

So tagObject itself will handle any clean-up work related to refs files for an unexpected exception raised, before re-raising it to the client.

plantUML Syntax

Actor "Client" as DOU
Participant "tagObject" as TO
Participant "storeHashStoreRefs" as TOS
Participant "untagObject" as UO

DOU -> TO: tagObject(pid, cid)
activate TO
TO -> TO: Start synchronization code
TO -> TOS: storeHashStoreRefs(pid, cid)
deactivate TO

Alt There are no issues
activate TOS
note over TOS: \nNormal Process\n
TOS --[#green]> TO: return
deactivate TOS
activate TO
TO -> TO: Exit synchronization code
TO --[#green]> DOU: return
deactivate TO
Else Something happens which we have no control over
activate TOS
note over TOS: \nUnexpected Exception\n
TOS --[#red]> TO: Raise Exception
deactivate TOS
activate TO
TO -> UO: untagObject(pid, cid)
deactivate TO
activate UO
UO -> UO: Revert the tagging process
UO --> TO: return
deactivate UO
activate TO
TO -> TO: Exit synchronization code
TO --[#red]> DOU: Raise Exception
deactivate TO

End


' change the default styles   
skinparam shadowing false   
skinparam roundcorner 5
skinparam padding 2
skinparam linetype ortho
skinparam bbackgroundColor #000000
skinparam stereotypeCBackgroundColor #C3D3E3


' style sequences
skinparam sequence {
	ArrowColor #1F4260
	LifeLineBorderColor #1F4260
	LifeLineBackgroundColor #428BCA
	ParticipantBorderColor #AAAAAA
	ParticipantBackgroundColor #F5F5F5
  ActorBackgroundColor #DDDDDD
  ActorBorderColor #333333
}

' style notes
skinparam noteFontColor #C49858
skinparam note {
  BackgroundColor #FCF8E4
  BorderColor #FCEED6   
}

[doulikecookiedough]

This has been completed via Feature-83: tagObject Refactor