org.eclipse.jgit.storage.file
Class ObjectDirectory

java.lang.Object
  org.eclipse.jgit.lib.ObjectDatabase
      org.eclipse.jgit.storage.file.ObjectDirectory

public class ObjectDirectory
extends ObjectDatabase

Traditional file system based ObjectDatabase.

This is the classical object database representation for a Git repository, where objects are stored loose by hashing them into directories by their ObjectId, or are stored in compressed containers known as PackFiles.

Optionally an object database can reference one or more alternates; other ObjectDatabase instances that are searched in addition to the current database.

Databases are divided into two halves: a half that is considered to be fast to search (the PackFiles), and a half that is considered to be slow to search (loose objects). When alternates are present the fast half is fully searched (recursively through all alternates) before the slow half is considered.

Constructor Summary

ObjectDirectory(Config cfg, File dir, File[] alternatePaths, FS fs)
Initialize a reference to an on-disk object directory.

Method Summary

void	close() Close any resources held by this database.
void	create() Initialize a new object database at this location.
boolean	exists() Does this database exist yet?
File	fileFor(AnyObjectId objectId) Compute the location of a loose object file.
File	getDirectory()
Collection<PackFile>	getPacks()
boolean	has(AnyObjectId objectId) Does the requested object exist in this database?
ObjectDatabase	newCachedDatabase() Create a new cached database instance over this database.
org.eclipse.jgit.storage.file.ObjectDirectoryInserter	newInserter() Create a new ObjectInserter to insert new objects.
ObjectReader	newReader() Create a new ObjectReader to read existing objects.
PackFile	openPack(File pack, File idx) Add a single existing pack to the list of available pack files.
String	toString()

Methods inherited from class org.eclipse.jgit.lib.ObjectDatabase

open, open

Methods inherited from class java.lang.Object

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

Constructor Detail

ObjectDirectory

public ObjectDirectory(Config cfg,
                       File dir,
                       File[] alternatePaths,
                       FS fs)
                throws IOException

Initialize a reference to an on-disk object directory.

Parameters:

cfg - configuration this directory consults for write settings.

dir - the location of the objects directory.

alternatePaths - a list of alternate object directories

fs - the file system abstraction which will be necessary to perform certain file system operations.

Throws:

IOException - an alternate object cannot be opened.

Method Detail

getDirectory

public final File getDirectory()

Returns:

the location of the objects directory.

exists

public boolean exists()

Description copied from class: ObjectDatabase

Does this database exist yet?

Overrides:

exists in class ObjectDatabase

Returns:

true if this database is already created; false if the caller should invoke ObjectDatabase.create() to create this database location.

create

public void create()
            throws IOException

Description copied from class: ObjectDatabase

Initialize a new object database at this location.

Overrides:

create in class ObjectDatabase

Throws:

IOException - the database could not be created.

newInserter

public org.eclipse.jgit.storage.file.ObjectDirectoryInserter newInserter()

Description copied from class: ObjectDatabase

Create a new ObjectInserter to insert new objects.

The returned inserter is not itself thread-safe, but multiple concurrent inserter instances created from the same ObjectDatabase must be thread-safe.

Returns:

writer the caller can use to create objects in this database.

close

public void close()

Description copied from class: ObjectDatabase

Close any resources held by this database.

Specified by:

close in class ObjectDatabase

fileFor

public File fileFor(AnyObjectId objectId)

Compute the location of a loose object file.

Parameters:

objectId - identity of the loose object to map to the directory.

Returns:

location of the object, if it were to exist as a loose object.

getPacks

public Collection<PackFile> getPacks()

Returns:

unmodifiable collection of all known pack files local to this directory. Most recent packs are presented first. Packs most likely to contain more recent objects appear before packs containing objects referenced by commits further back in the history of the repository.

openPack

public PackFile openPack(File pack,
                         File idx)
                  throws IOException

Add a single existing pack to the list of available pack files.

Parameters:

pack - path of the pack file to open.

idx - path of the corresponding index file.

Returns:

the pack that was opened and added to the database.

Throws:

IOException - index file could not be opened, read, or is not recognized as a Git pack file index.

toString

public String toString()

Overrides:

toString in class Object

newCachedDatabase

public ObjectDatabase newCachedDatabase()

Description copied from class: ObjectDatabase

Create a new cached database instance over this database. This instance might optimize queries by caching some information about database. So some modifications done after instance creation might fail to be noticed.

Overrides:

newCachedDatabase in class ObjectDatabase

Returns:

new cached database instance

newReader

public ObjectReader newReader()

Description copied from class: ObjectDatabase

Create a new ObjectReader to read existing objects.

The returned reader is not itself thread-safe, but multiple concurrent reader instances created from the same ObjectDatabase must be thread-safe.

Specified by:

newReader in class ObjectDatabase

Returns:

reader the caller can use to load objects from this database.

has

public boolean has(AnyObjectId objectId)

Does the requested object exist in this database?

Alternates (if present) are searched automatically.

Overrides:

has in class ObjectDatabase

Parameters:

objectId - identity of the object to test for existence of.

Returns:

true if the specified object is stored in this database, or any of the alternate databases.