Reading Entries

Configuration files can contain entries for anything from primitive types up to complex hierarchies of POJOs consisting of Maps, Collections, and/or beans.

Entries are accessed via the Config.get(String) method which returns the following bean:

Entry get() isNotEmpty() isPresent() orElse(String) orElseGet(Supplier) as(Class) as(Parser,Class) as(Parser,Type,Type...) as(Type,Type...) asBoolean() asBytes() asDouble() asFloat() asInteger() asList() asList(Parser) asLong() asMap() asMap(Parser) asString() asStringArray() getComment() getKey() getModifiers() getPreLines() getValue()

The most common case for configuration values are primitives.

# A string
key1 = foo

# A boolean
key2 = true

# An integer
key3 = 123

# A long
key4 = 10000000000

# Doubles
key5 = 6.67e−11
key6 = Infinity

On integers and longs, "K", "M", and "G" can be used to identify kilo, mega, and giga.

key1 = 100K  # Same as 1024000
key2 = 100M  # Same as 104857600

Numbers can also use hexadecimal and octal notation:

hex1 = 0x12FE
hex2 = 0X12FE
octal1 = 01234

Strings with newlines are treated as multi-line values that get broken into separate lines:

key1 = This is a particularly long sentence that we want to split
    onto separate lines.

Typically, multi-line values are started on the next line for clarity like so:

key1 =
    This is a particularly long sentence that we want to split
    onto separate lines.

POJOs

Entries can also be read as POJOs.

In theory, any parsable POJO type can be represented as a config value. However in practice, we're typically talking about the following:

• Objects convertible from Strings.
• Beans.

An example of an object convertible from a String was already shown in an example above. In that case, it was a URL which has a public constructor that takes in a String:

# A POJO
key4 = http://bar

// Read values from section #1
URL key4 = config.get("Section1/key4").as(URL.class).orElse(null);

Beans are represented as JSON 5 by default:

// Contact information
[ContactInfo]
address =
    {
        street: '123 Main Street',
        city: 'Anywhere',
        state: 'NY',
        zip: 12345
    }

// Example bean
public class Address {
    public String street, city;
    public StateEnum state;
    public int zip;
}

// Example usage
Config config = Config.create("MyConfig.cfg").build();
Address myAddress = config.get("ContactInfo/address").as(Address.class).orElse(null);

The default serializer and parser is registered on the Config through the following methods:

Config.Builderserializer(WriterSerializer)parser(ReaderParser)

Arrays

The asStringArray() method allows you to retrieve comma-delimited lists of values:

key1 = foo, bar, baz

String[] key1 = config.get("key1").asStringArray().orElse(null);

String arrays can also be represented in JSON when the registered parser is a JSON parser:

key1 = ['foo','bar','baz']

String[] key1 = config.get("key1").asStringArray().orElse(null);

Primitive arrays can also be retrieved using the as() methods:

key1 = [1,2,3]

int[] key1 = config.get("key1").as(int[].class).orElse(null);

Arrays of POJOs can also be retrieved using the methods as well:

addresses =
    [
        {
            street: '123 Main Street',
            city: 'Anywhere',
            state: 'NY',
            zip: 12345
        },
        {
            street: '456 Main Street',
            city: 'Anywhere',
            state: 'NY',
            zip: 12345
        }
    ]

Address[] addresses = config.get("addresses").as(Address[].class).orElse(null);

Binary data

Entries can also be accessed as binary data.

Binary data can be represented in 3 formats:

Format	Example
BASE-64 (default)	Zm9vYmFycw==
Hexadecimal	666F6F62617273
Spaced hexadecimal	66 6F 6F 62 61 72 73

The binary data format is controlled via the following setting:

Config.BuilderbinaryFormat(BinaryFormat)

Example

key = Zm9vYmFycw==

byte[] bytes = config.get("key").asBytes().orElse(null);

Binary lines can be split up into separate lines for readability:

key =
    Zm9vYm
    Fycw==

Binary data line wrapping can be controlled via the following setting:

Config.BuilderbinaryLineLength(int)

In This Section

📄️ 2.5.2.1. Java Collection Framework Objects

Entries can also be read as Java Collection Framework objects.