Package com.google.gerrit.server.notedb

Class RepoSequence

java.lang.Object

com.google.gerrit.server.notedb.RepoSequence

All Implemented Interfaces:

Sequence

public class RepoSequence
extends Object
implements Sequence

Class for managing an incrementing sequence backed by a git repository.

The current sequence number is stored as UTF-8 text in a blob pointed to by a ref in the refs/sequences/* namespace. Multiple processes can share the same sequence by incrementing the counter using normal git ref updates. To amortize the cost of these ref updates, processes can increment the counter by a larger number and hand out numbers from that range in memory until they run out. This means concurrent processes will hand out somewhat non-monotonic numbers.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	RepoSequence.DisabledGitRefUpdatedRepoGroupsSequenceProvider	A groups sequence provider that does not fire git reference updates.
static class	RepoSequence.RepoSequenceModule
static interface	RepoSequence.Seed

Nested classes/interfaces inherited from interface com.google.gerrit.server.Sequence

Sequence.LightweightAccounts, Sequence.LightweightGroups, Sequence.SequenceType

Field Summary

Fields inherited from interface com.google.gerrit.server.Sequence

NAME_ACCOUNTS, NAME_CHANGES, NAME_GROUPS

Constructor Summary

Constructors

Constructor	Description
RepoSequence(GitRepositoryManager repoManager, GitReferenceUpdated gitRefUpdated, Project.NameKey projectName, String name, RepoSequence.Seed seed, int batchSize)

Method Summary

Modifier and Type	Method	Description
int	current()	Returns the next available sequence value.
int	last()	Retrieves the last returned sequence number.
int	next()	Retrieves the next available sequence number.
com.google.common.collect.ImmutableList<Integer>	next(int count)	Retrieves the next N available sequence number.
void	storeNew(int value)	Stores a new value to be returned on the next calls for Sequence.next() or Sequence.current().

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

RepoSequence

public RepoSequence(GitRepositoryManager repoManager,
 GitReferenceUpdated gitRefUpdated,
 Project.NameKey projectName,
 String name,
 RepoSequence.Seed seed,
 int batchSize)

Method Details

next

public int next()

Retrieves the next available sequence number.

This method is thread-safe.

Specified by:

next in interface Sequence

Returns:

the next available sequence number

next

public com.google.common.collect.ImmutableList<Integer> next(int count)

Retrieves the next N available sequence number.

This method is thread-safe.

Specified by:

next in interface Sequence

Parameters:

count - the number of sequence numbers which should be returned

Returns:

the next N available sequence numbers

storeNew

public void storeNew(int value)

Description copied from interface: Sequence

Stores a new value to be returned on the next calls for Sequence.next() or Sequence.current().

Specified by:

storeNew in interface Sequence

current

public int current()

Description copied from interface: Sequence

Returns the next available sequence value.

Specified by:

current in interface Sequence

last

public int last()

Retrieves the last returned sequence number.

Explicitly calls next() if this instance didn't return sequence number until now.

Specified by:

last in interface Sequence