com.apple.foundationdb.directory

Class DirectorySubspace

java.lang.Object

com.apple.foundationdb.subspace.Subspace

com.apple.foundationdb.directory.DirectorySubspace

All Implemented Interfaces:

Directory

public class DirectorySubspace
extends Subspace
implements Directory

A DirectorySubspace represents the contents of a directory, but it also remembers the path with which it was opened and offers convenience methods to operate on the directory at that path.

An instance of DirectorySubspace can be used for all the usual subspace operations. It can also be used to operate on the directory with which it was opened.

Method Summary

Modifier and Type	Method and Description
java.util.concurrent.CompletableFuture<DirectorySubspace>	create(TransactionContext tcx, java.util.List<java.lang.String> subpath, byte[] otherLayer, byte[] prefix) Creates a subdirectory of this Directory located at subpath (creating parent directories if necessary).
java.util.concurrent.CompletableFuture<DirectorySubspace>	createOrOpen(TransactionContext tcx, java.util.List<java.lang.String> subpath, byte[] otherLayer) Creates or opens the subdirectory of this Directory located at subpath (creating parent directories, if necessary).
boolean	equals(java.lang.Object rhs) Returns whether this DirectorySubspace is equal to rhs.
java.util.concurrent.CompletableFuture<java.lang.Boolean>	exists(ReadTransactionContext tcx, java.util.List<java.lang.String> subpath) Checks if the subdirectory of this Directory located at subpath exists.
DirectoryLayer	getDirectoryLayer() Get the DirectoryLayer that was used to create this Directory.
byte[]	getLayer() Gets the layer byte string that was stored when this Directory was created.
java.util.List<java.lang.String>	getPath() Gets the path represented by this Directory.
int	hashCode() Computes a hash code compatible with the equals() method of this class.
java.util.concurrent.CompletableFuture<java.util.List<java.lang.String>>	list(ReadTransactionContext tcx, java.util.List<java.lang.String> subpath) List the subdirectories of this directory at a given subpath.
java.util.concurrent.CompletableFuture<DirectorySubspace>	move(TransactionContext tcx, java.util.List<java.lang.String> oldSubpath, java.util.List<java.lang.String> newSubpath) Moves the subdirectory of this Directory located at oldSubpath to newSubpath.
java.util.concurrent.CompletableFuture<DirectorySubspace>	moveTo(TransactionContext tcx, java.util.List<java.lang.String> newAbsolutePath) Moves this Directory to the specified newAbsolutePath.
java.util.concurrent.CompletableFuture<DirectorySubspace>	open(ReadTransactionContext tcx, java.util.List<java.lang.String> subpath, byte[] otherLayer) Opens the subdirectory of this Directory located at subpath.
java.util.concurrent.CompletableFuture<java.lang.Void>	remove(TransactionContext tcx, java.util.List<java.lang.String> subpath) Removes the subdirectory of this Directory located at subpath and all of its subdirectories, as well as all of their contents.
java.util.concurrent.CompletableFuture<java.lang.Boolean>	removeIfExists(TransactionContext tcx, java.util.List<java.lang.String> subpath) Removes the subdirectory of this Directory located at subpath and all of its subdirectories, as well as all of their contents.
java.lang.String	toString() Create a human-readable string representation of this subspace.

Methods inherited from class com.apple.foundationdb.subspace.Subspace

contains, get, get, getKey, pack, pack, pack, packWithVersionstamp, range, range, subspace, unpack

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.apple.foundationdb.directory.Directory

create, create, createOrOpen, exists, list, open, remove, removeIfExists

Method Detail

toString

public java.lang.String toString()

Description copied from class: Subspace

Create a human-readable string representation of this subspace. This is really only useful for debugging purposes, but it includes information on what raw prefix the subspace is using.

Overrides:

toString in class Subspace

Returns:

a printable representation of this DirectorySubspace

equals

public boolean equals(java.lang.Object rhs)

Returns whether this DirectorySubspace is equal to rhs. Two DirectorySubspaces are equal if they were created by the same DirectoryLayer and have the same path, layer, and subspace prefix.

Overrides:

equals in class Subspace

Parameters:

rhs - the Object to test for equality

Returns:

true if this is equal to rhs

hashCode

public int hashCode()

Computes a hash code compatible with the equals() method of this class. In particular, it will produce a hash code that is based off of the hashes of its path, its layer, and its subspace prefix.

Overrides:

hashCode in class Subspace

Returns:

a hash compatible with this class's equals() method

getPath

public java.util.List<java.lang.String> getPath()

Description copied from interface: Directory

Gets the path represented by this Directory.

Specified by:

getPath in interface Directory

Returns:

this Directory's path

getLayer

public byte[] getLayer()

Description copied from interface: Directory

Gets the layer byte string that was stored when this Directory was created.

Specified by:

getLayer in interface Directory

Returns:

this Directory's layer byte string

getDirectoryLayer

public DirectoryLayer getDirectoryLayer()

Description copied from interface: Directory

Get the DirectoryLayer that was used to create this Directory.

Specified by:

getDirectoryLayer in interface Directory

Returns:

the DirectoryLayer that created this Directory

createOrOpen

public java.util.concurrent.CompletableFuture<DirectorySubspace> createOrOpen(TransactionContext tcx,
                                                                              java.util.List<java.lang.String> subpath,
                                                                              byte[] otherLayer)

Description copied from interface: Directory

Creates or opens the subdirectory of this Directory located at subpath (creating parent directories, if necessary). If the directory is new, then the layer byte string will be recorded as its layer. If the directory already exists, the layer byte string will be compared against the layer set when the directory was created.

The returned CompletableFuture can be set to the following errors:

• MismatchedLayerException - if the directory has already been created with a different layer byte string

Specified by:

createOrOpen in interface Directory

Parameters:

tcx - the TransactionContext to execute this operation in

subpath - a List<String> specifying a subpath of this Directory

otherLayer - a byte[] specifying a layer to set on a new directory or check for on an existing directory

Returns:

a CompletableFuture which will be set to the created or opened DirectorySubspace

open

public java.util.concurrent.CompletableFuture<DirectorySubspace> open(ReadTransactionContext tcx,
                                                                      java.util.List<java.lang.String> subpath,
                                                                      byte[] otherLayer)

Description copied from interface: Directory

Opens the subdirectory of this Directory located at subpath. The layer byte string will be compared against the layer set when the directory was created.

The returned CompletableFuture can be set to the following errors:

• MismatchedLayerException - if the directory was created with a different layer byte string
• NoSuchDirectoryException - if the directory does not exist

Specified by:

open in interface Directory

Parameters:

tcx - the ReadTransactionContext to execute this operation in

subpath - a List<String> specifying a subpath of this Directory

otherLayer - a byte[] specifying the expected layer

Returns:

a CompletableFuture which will be set to the opened DirectorySubspace

create

public java.util.concurrent.CompletableFuture<DirectorySubspace> create(TransactionContext tcx,
                                                                        java.util.List<java.lang.String> subpath,
                                                                        byte[] otherLayer,
                                                                        byte[] prefix)

Description copied from interface: Directory

Creates a subdirectory of this Directory located at subpath (creating parent directories if necessary). The layer byte string will be recorded as the new directory's layer and checked by future calls to Directory.open(ReadTransactionContext, List, byte[]). The specified prefix will be used for this directory's contents instead of allocating a prefix automatically.

The returned CompletableFuture can be set to the following errors:

• DirectoryAlreadyExistsException - if the given directory already exists

Specified by:

create in interface Directory

Parameters:

tcx - the TransactionContext to execute this operation in

subpath - a List<String> specifying a subpath of this Directory

otherLayer - a byte[] specifying a layer to set for the directory

prefix - a byte[] specifying the key prefix to use for the directory's contents

Returns:

a CompletableFuture which will be set to the created DirectorySubspace

list

public java.util.concurrent.CompletableFuture<java.util.List<java.lang.String>> list(ReadTransactionContext tcx,
                                                                                     java.util.List<java.lang.String> subpath)

Description copied from interface: Directory

List the subdirectories of this directory at a given subpath.

The returned CompletableFuture can be set to the following errors:

• NoSuchDirectoryException - if no directory exists at subpath

Specified by:

list in interface Directory

Parameters:

tcx - the ReadTransactionContext to execute this operation in

subpath - a List<String> specifying a subpath of this Directory

Returns:

a CompletableFuture which will be set to a List<String> of names of the subdirectories of the directory at subpath. Each name is a unicode string representing the last component of a subdirectory's path.

move

public java.util.concurrent.CompletableFuture<DirectorySubspace> move(TransactionContext tcx,
                                                                      java.util.List<java.lang.String> oldSubpath,
                                                                      java.util.List<java.lang.String> newSubpath)

Description copied from interface: Directory

Moves the subdirectory of this Directory located at oldSubpath to newSubpath.

There is no effect on the physical prefix of the given directory, or on clients that already have the directory open.

It is invalid to move a directory to:

• A location where a directory already exists
• A location whose parent does not exist
• A subdirectory of itself
• A different partition

The returned CompletableFuture can be set to the following errors:

• NoSuchDirectoryException - if no Directory exists at oldSubpath
• DirectoryAlreadyExistsException - if a directory already exists at newSubpath
• DirectoryMoveException - if an invalid move location is specified

Specified by:

move in interface Directory

Parameters:

tcx - the TransactionContext to execute this operation in

oldSubpath - a List<String> specifying the subpath of the directory to move

newSubpath - a List<String> specifying the subpath to move to

Returns:

a CompletableFuture which will be set to the DirectorySubspace for this Directory at its new location.

moveTo

public java.util.concurrent.CompletableFuture<DirectorySubspace> moveTo(TransactionContext tcx,
                                                                        java.util.List<java.lang.String> newAbsolutePath)

Description copied from interface: Directory

Moves this Directory to the specified newAbsolutePath.

There is no effect on the physical prefix of the given directory, or on clients that already have the directory open.

It is invalid to move a directory to:

• A location where a directory already exists
• A location whose parent does not exist
• A subdirectory of itself
• A different partition

The returned CompletableFuture can be set to the following errors:

• NoSuchDirectoryException - if this Directory doesn't exist
• DirectoryAlreadyExistsException - if a directory already exists at newAbsolutePath
• DirectoryMoveException - if an invalid move location is specified

Specified by:

moveTo in interface Directory

Parameters:

tcx - the TransactionContext to execute this operation in

newAbsolutePath - a List<String> specifying the new absolute path for this Directory

Returns:

a CompletableFuture which will be set to the DirectorySubspace for this Directory at its new location.

remove

public java.util.concurrent.CompletableFuture<java.lang.Void> remove(TransactionContext tcx,
                                                                     java.util.List<java.lang.String> subpath)

Description copied from interface: Directory

Removes the subdirectory of this Directory located at subpath and all of its subdirectories, as well as all of their contents.

Warning: Clients that have already opened the directory might still insert data into its contents after it is removed.

The returned CompletableFuture can be set to the following errors:

• NoSuchDirectoryException - if no directory exists at subpath

Specified by:

remove in interface Directory

Parameters:

tcx - the TransactionContext to execute this operation in

subpath - a List<String> specifying a subpath of this Directory

Returns:

a CompletableFuture which will be set once the Directory has been removed

removeIfExists

public java.util.concurrent.CompletableFuture<java.lang.Boolean> removeIfExists(TransactionContext tcx,
                                                                                java.util.List<java.lang.String> subpath)

Description copied from interface: Directory

Removes the subdirectory of this Directory located at subpath and all of its subdirectories, as well as all of their contents.

Warning: Clients that have already opened the directory might still insert data into its contents after it is removed.

Specified by:

removeIfExists in interface Directory

Parameters:

tcx - the TransactionContext to execute this operation in

subpath - a List<String> specifying a subpath of this Directory

Returns:

a CompletableFuture which will be set to true once the Directory has been removed, or false if it didn't exist.

exists

public java.util.concurrent.CompletableFuture<java.lang.Boolean> exists(ReadTransactionContext tcx,
                                                                        java.util.List<java.lang.String> subpath)

Description copied from interface: Directory

Checks if the subdirectory of this Directory located at subpath exists.

Specified by:

exists in interface Directory

Parameters:

tcx - the TransactionContext to execute this operation in

subpath - a List<String> specifying a subpath of this Directory

Returns:

a CompletableFuture which will be set to true if the specified subdirectory exists, or false if it doesn't