INI Config Format

A config file's on-disk syntax is handled by a ConfigFormat. IniConfigFormat is the INI implementation and the default. The other built-in implementation is YamlConfigFormat (see YAML Config Files).

See the guide: Externalize config with INI/YAML and variables

Selecting the format

Config.Builderini()yaml()format(ConfigFormat)

If no format is set explicitly, it is auto-detected from the config name: a name ending in .yaml or .yml (case-insensitive) selects YAML, and anything else selects INI. So MyConfig.cfg, MyConfig.properties or a name with no extension all use INI.

Example

// INI by name (default).
Config c1 = Config.create("MyConfig.cfg").build();

// Force INI explicitly, e.g. for a file whose name would otherwise look like YAML.
Config c2 = Config.create("MyConfig.yaml").ini().build();

// Equivalent, passing the singleton directly.
Config c3 = Config.create("MyConfig.yaml").format(IniConfigFormat.INSTANCE).build();

The INI syntax

INI is the native syntax of the juneau-config module: [Section] headers, key = value entries, # comments, imports, and value modifiers. Because it is the native syntax, the INI format passes the file contents through unchanged when reading, and when writing it emits the in-memory config directly, preserving the comments and whitespace of the original file. See the juneau-config overview and Reading Entries.

# A set of entries
[Section1]

# An integer
key1 = 1

# A boolean
key2 = true

The ConfigFormat contract

ConfigFormat is the extension point for alternative file syntaxes. Every config is held internally as INI-style text; a format translates to and from that representation:

Method	Purpose
id()	Format identifier. IniConfigFormat returns "ini"; YamlConfigFormat returns "yaml".
toInternal(String)	Normalizes source text into the INI-style content used internally.
fromInternal(ConfigMap)	Serializes the config back to this format.

For IniConfigFormat, toInternal returns the input unchanged (an empty string for null), and fromInternal writes the INI text of the config. The singleton is available as IniConfigFormat.INSTANCE.