Directories

Introduction

• a tiny library (12kB) with a minimal API
• that provides the platform-specific, user-accessible locations
• for retrieving and storing configuration, cache and other data
• on Linux, Windows (≥ 7), macOS and BSD

The library provides the location of these directories by leveraging the mechanisms defined by

• the XDG base directory and the XDG user directory specifications on Linux
• the Known Folder API on Windows
• the Standard Directories guidelines on macOS

Platforms

This library is written in Java, and runs on the JVM (≥ 6).

A version of this library implemented in Rust is provided by directories-rs.

Usage

Dependency

Add the library as a dependency to your project:

Maven

<dependency>
  <groupId>io.github.soc</groupId>
  <artifactId>directories</artifactId>
  <version>11</version>
</dependency>

Gradle

compile 'io.github.soc:directories:11'

SBT

"io.github.soc" % "directories" % "11"

The library itself is built against Java 6 to allow for the widest possible usage scenarios. It can be used on any Java version >= 6.

Example

Library run by user Alice:

import io.github.soc.directories.ProjectDirectories;
import io.github.soc.directories.BaseDirectories;
import io.github.soc.directories.UserDirectories;

ProjectDirectories myProjDirs = ProjectDirectories.from("com", "Foo Corp", "Bar App");
myProjDirs.configDir;
// Lin: /home/alice/.config/barapp
// Mac: /Users/Alice/Library/Preferences/com.Foo-Corp.Bar-App
// Win: C:\Users\Alice\AppData\Roaming\Foo Corp\Bar App\config

BaseDirectories baseDirs = BaseDirectories.get();
baseDirs.executableDir;
// Lin: /home/alice/.local/bin
// Mac: null
// Win: null

UserDirectories userDirs = UserDirectories.get();
userDirs.audioDir;
// Lin: /home/alice/Music
// Mac: /Users/Alice/Music
// Win: C:\Users\Alice\Music

Design Goals

• The directories library is designed to provide an accurate snapshot of the system's state at the point of invocation of BaseDirectories.get(), UserDirectories.get() or ProjectDirectories.from(). Subsequent changes to the state of the system are not reflected in instances created prior to such a change.
• This library does not create directories or check for their existence. The library only provides information on what the path to a certain directory should be. How this information is used is a decision that developers need to make based on the requirements of each individual application.
• This library is intentionally focused on providing information on user-writable directories only. There is no discernible benefit in returning a path that points to a user-level, writable directory on one operating system, but a system-level, read-only directory on another, that would outweigh the confusion and unexpected failures such an approach would cause.
  • executableDir is specified to provide the path to a user-writable directory for binaries.
    As such a directory only commonly exists on Linux, it returns null on macOS and Windows.
  • fontDir is specified to provide the path to a user-writable directory for fonts.
    As such a directory only exists on Linux and macOS, it returns null Windows.
  • runtimeDir is specified to provide the path to a directory for non-essential runtime data. It is required that this directory is created when the user logs in, is only accessible by the user itself, is deleted when the user logs out, and supports all filesystem features of the operating system.
    As such a directory only commonly exists on Linux, it returns null on macOS and Windows.

Features

BaseDirectories

The intended use-case for BaseDirectories is to query the paths of user-invisible standard directories that have been defined according to the conventions of the operating system the library is running on.

If you want to compute the location of cache, config or data folders for your own application or project, use ProjectDirectories instead.

Field name	Value on Linux / BSD	Value on Windows	Value on macOS
homeDir	$HOME	{FOLDERID_UserProfile}	$HOME
cacheDir	$XDG_CACHE_HOME or $HOME/.cache	{FOLDERID_LocalApplicationData}	$HOME/Library/Caches
configDir	$XDG_CONFIG_HOME or $HOME/.config	{FOLDERID_ApplicationData}	$HOME/Library/Preferences
dataDir	$XDG_DATA_HOME or $HOME/.local/share	{FOLDERID_ApplicationData}	$HOME/Library/Application Support
dataLocalDir	$XDG_DATA_HOME or $HOME/.local/share	{FOLDERID_LocalApplicationData}	$HOME/Library/Application Support
executableDir	$XDG_BIN_HOME or $XDG_DATA_HOME/../bin or $HOME/.local/bin	null	null
runtimeDir	$XDG_RUNTIME_DIR or null	null	null

UserDirectories

The intended use-case for UserDirectories is to query the paths of user-facing standard directories that have been defined according to the conventions of the operating system the library is running on.

Field name	Value on Linux / BSD	Value on Windows	Value on macOS
homeDir	$HOME	{FOLDERID_UserProfile}	$HOME
audioDir	XDG_MUSIC_DIR	{FOLDERID_Music}	$HOME/Music
desktopDir	XDG_DESKTOP_DIR	{FOLDERID_Desktop}	$HOME/Desktop
documentDir	XDG_DOCUMENTS_DIR	{FOLDERID_Documents}	$HOME/Documents
downloadDir	XDG_DOWNLOAD_DIR	{FOLDERID_Downloads}	$HOME/Downloads
fontDir	$XDG_DATA_HOME/fonts or $HOME/.local/share/fonts	null	$HOME/Library/Fonts
pictureDir	XDG_PICTURES_DIR	{FOLDERID_Pictures}	$HOME/Pictures
publicDir	XDG_PUBLICSHARE_DIR	{FOLDERID_Public}	$HOME/Public
templateDir	XDG_TEMPLATES_DIR	{FOLDERID_Templates}	null
videoDir	XDG_VIDEOS_DIR	{FOLDERID_Videos}	$HOME/Movies

ProjectDirectories

The intended use-case for BaseDirectories is to compute the location of cache, config or data folders for your own application or project, which are derived from the standard directories.

Field name	Value on Linux / BSD	Value on Windows	Value on macOS
cacheDir	$XDG_CACHE_HOME/<project_path> or $HOME/.cache/<project_path>	{FOLDERID_LocalApplicationData}/<project_path>/cache	$HOME/Library/Caches/<project_path>
configDir	$XDG_CONFIG_HOME/<project_path> or $HOME/.config/<project_path>	{FOLDERID_ApplicationData}/<project_path>	$HOME/Library/Preferences/<project_path>
dataDir	$XDG_DATA_HOME/<project_path> or $HOME/.local/share/<project_path>	{FOLDERID_ApplicationData}/<project_path>	$HOME/Library/Application Support/<project_path>
dataLocalDir	$XDG_DATA_HOME/<project_path> or $HOME/.local/share/<project_path>	{FOLDERID_LocalApplicationData}/<project_path>	$HOME/Library/Application Support/<project_path>
runtimeDir	$XDG_RUNTIME_DIR/<project_path>	null	null

The specific value of <project_path> is computed by the

ProjectDirectories.from(String qualifier,
                        String organization,
                        String application)

method and varies across operating systems. As an example, calling

ProjectDirectories.from("org"         /*qualifier*/,
                        "Baz Corp"    /*organization*/,
                        "Foo Bar-App" /*application*/)

results in the following values:

Value on Linux	Value on Windows	Value on macOS
"foobar-app"	"Baz Corp/Foo Bar-App"	"org.Baz-Corp.Foo-Bar-App"

The ProjectDirectories.fromPath method allows the creation of ProjectDirectories instances directly from a project path. This argument is used verbatim and is not adapted to operating system standards. The use of ProjectDirectories.fromPath is strongly discouraged, as its results will not follow operating system standards on at least two of three platforms.

Versioning

The version number of this library consists of a whole number, which is incremented with each release. (Think semantic versioning without minor and patch versions.)

Changelog

11 – current stable version

• Throw RuntimeExceptions instead of catching IOExceptions and returning null if directory lookup on Windows fails. This should make it easier to diagnose issues.
• Add Automatic-Module-Name to manifest file, enabling support for Java 9 modules.
• Some small cleanups.

10

• Full Windows support: downloadDir and publicDir are now supported.
• Improved speed on Windows and Linux.
• Changed static fields in BaseDirectories and UserDirectories to instance fields. Instances can be created with BaseDirectories.get() and UserDirectories.get().

9

• Windows:
  • Fixed the implementation of audioDir, desktopDir, documentDir, pictureDir and videoDir.
  • Clarified that downloadDir and publicDir return null on Windows, as the SpecialFolder enumeration lacks entries for these values.

8

• Windows:
  • Fixed incorrect ProjectDirectories paths for cacheDir, configDir and dataDir.
• Linux:
  • Fixed incorrect ProjectDirectories paths for cacheDir, configDir, dataDir and dataLocalDir if XDG environment variables are set.
  • Fixed incorrect UserDirectories paths for fontDir if XDG environment variables are set.

7

• Split BaseDirectories into BaseDirectories (cache, config, ...) and UserDirectories (audio, video, ...).
• Fields of BaseDirectories and UserDirectories are now public.
• Add substantial amounts of documentation.
• The fields of UserDirectories are now null if no values can be retrieved from xdg-user-dirs, instead of falling back on hard-coded values.
• A user's home directory is now retrieved with System.getProperty("user.home") instead of System.getenv("HOME"), improving reliability and portability.
• Changes to some values of BaseDirectories and ProjectDirectories:

Method	Old value	New Value
BaseDirectories.cacheDir	{SpecialFolder.LocalApplicationData}/cache	{SpecialFolder.LocalApplicationData}
ProjectDirectories#dataDir	{SpecialFolder.ApplicationData}/<project_path>	{SpecialFolder.ApplicationData}/<project_path>/data
ProjectDirectories#dataLocalDir	{SpecialFolder.LocalApplicationData}/<project_path>	{SpecialFolder.LocalApplicationData}/<project_path>/data

6

• More consistent and intuitive naming scheme (all names are singular now):

Old name	New name
dataDir	dataLocalDir
dataRoamingDir	dataDir
executablesDir	executableDir
documentsDir	documentDir
downloadsDir	downloadDir
fontsDir	fontDir
musicDir	audioDir
picturesDir	pictureDir
templatesDir	templateDir
videosDir	videoDir

• ProjectDirectories factory methods have been overhauled and replaced with a single from(String qualifier, String organization, String project) method.

• Changes to the selection of local/roaming data directories:

  • dataDir selects the roaming data directory on Windows (no change on Linux or macOS).
  • dataLocalDir selects the local data directory on Windows (no change on Linux or macOS).

• ProjectDirectories received a runtimeDir field.

• ProjectDirectories field names dropped the project prefix.

• Changes to the directory for executables:

  • Support for executableDir has been dropped on macOS.
  • The value of executableDir considers $XDG_BIN_HOME now, before falling back to $XDG_DATA_HOME/../bin and $HOME/.local/bin.