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1011 lines
37 KiB
Markdown
# ConfigLib
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**A Minecraft library for saving, loading, updating, and commenting YAML
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configuration files.**
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This library facilitates creating, saving, loading, updating, and commenting
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YAML configuration files. It does so by automatically mapping instances of
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configuration classes to serializable maps which are first transformed into YAML
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and then saved to some specified file.
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Information on how to [import](#import) this library can be found at the end of
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this documentation. For a step-by-step tutorial that shows most features of this
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library in action check out
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the [Tutorial](https://github.com/Exlll/ConfigLib/wiki/Tutorial) page on the
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wiki!
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## Features
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* Automatic creation, saving, loading, and updating of configuration files
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* Support for comments through annotations
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* Support for all primitive types, their wrapper types, and strings
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* Support for all Java enums, records, and POJOs (+ inheritance!)
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* Support for (nested) lists, sets, arrays, and maps
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* Support for `BigInteger` and `BigDecimal`
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* Support for `LocalDate`, `LocalTime`, `LocalDateTime`, and `Instant`
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* Support for `UUID`, `File`, `Path`, `URL`, and `URI`
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* Support for Bukkit's `ConfigurationSerializable` types (e.g. `ItemStack`)
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* Option to format the names of configuration elements
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* Option to exclude fields from being converted
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* Option to customize null handling
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* Option to customize serialization by providing your own serializers
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* Option to add headers and footers to configuration files
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* ...and a few more!
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## Usage example
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This section contains a short usage example to get you started. The whole range
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of features is discussed in the following sections. Information on how
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to [import](#import) this library is located at the end of this documentation.
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For a step-by-step tutorial with a more advanced example check out
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the [Tutorial](https://github.com/Exlll/ConfigLib/wiki/Tutorial) page on the
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wiki.
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If you want support for Bukkit classes like `ItemStack`, check out
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the [Configuration properties](#configuration-properties) section.
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```java
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public final class Example {
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// * To create a configuration annotate a class with @Configuration and make sure that
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// it has a no-args constructor.
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// * Now add fields to that class and assign them default values.
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// * That's it! Fields can be private; setters are not required.
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@Configuration
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public static class BaseConfiguration {
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private String host = "127.0.0.1";
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private int port = 1234;
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// The library supports lists, sets, and maps.
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private Set<String> blockedAddresses = Set.of("8.8.8.8");
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// Fields can be ignored by making them final, transient, static or by
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// annotating them with @Ignore.
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private final double ignoreMe = 3.14;
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}
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// This library supports records; no @Configuration annotation required
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public record User(
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String username,
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@Comment("Please choose a strong password.")
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String password
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) {}
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// Subclassing of configurations and nesting of configurations in other configurations
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// is also supported. Subclasses don't need to be annotated again.
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public static final class UserConfiguration extends BaseConfiguration {
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// You can add comments with the @Comment annotation. Each string in the comment
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// array is written (as a comment) on a new line.
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@Comment({"The admin user has full access.", "Choose a proper password!"})
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User admin = new User("root", "toor"); // The User class is a record!
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List<User> blockedUsers = List.of(
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new User("user1", null), // null values are supported
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new User("user2", null)
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);
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}
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public static void main(String[] args) {
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var configFile = Paths.get("/tmp/config.yml");
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var config = new UserConfiguration();
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// Save an instance to the configuration file
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YamlConfigurations.save(configFile, UserConfiguration.class, config);
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// Load a new instance from the configuration file
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config = YamlConfigurations.load(configFile, UserConfiguration.class);
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System.out.println(config.admin.username);
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System.out.println(config.blockedUsers);
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// Modify the configuration and save it again
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config.blockedUsers.add(new User("user3", "pass3"));
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YamlConfigurations.save(configFile, UserConfiguration.class, config);
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}
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}
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```
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By running the above code, a new YAML configuration is created
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at `/tmp/config.yml`. Its content looks like this:
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```yaml
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host: 127.0.0.1
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port: 1234
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blockedAddresses:
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- 8.8.8.8
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# The admin user has full access.
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# Choose a proper password!
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admin:
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username: root
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# Please choose a strong password.
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password: toor
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blockedUsers:
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- username: user1
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- username: user2
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- username: user3
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password: pass3
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```
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Two things are noticeable here:
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1. Not every user in the `blockedUsers` list has a `password` mapping. This is
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because null values are not output by default. That behavior can be changed
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by the builder.
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2. The password of the user with username `user3` has no comment. This is due to
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limitations of the YAML library. Configurations in lists, sets, or maps
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cannot have their comments printed.
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## General information
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In the following sections the term _configuration type_ refers to any Java
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record type or to any non-generic class that is directly or indirectly (i.e.
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through subclassing) annotated with`@de.exlll.configlib.Configuration`.
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Accordingly, the term _configuration_ refers to an instance of such a type. A
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_configuration element_ is either a class field or a record component of a
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configuration type.
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### Declaring configuration types
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To declare a configuration type, either define a Java record or annotate a class
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with `@Configuration` and make sure that it has a no-args constructor. The
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no-args constructor can be `private`. Inner classes (i.e. the ones that are
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nested but not `static`) have an implicit synthetic constructor with at least
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one argument and are, therefore, not supported.
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Now simply add components to your record or fields to your class whose type is
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any of the supported types listed in the next section. You can (and should)
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initialize all fields of a configuration class with non-null default values.
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### Supported types
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A configuration type may only contain configuration elements of the following
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types:
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| Type class | Types |
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|-----------------------------|--------------------------------------------------------------------|
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| Boolean types | `boolean`, and `Boolean` |
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| Integer types | `byte`, `short`, `int`, `long`, and their respective wrapper types |
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| Floating point types | `float`, `double`, and their respective wrapper types |
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| Characters and strings | `char`, `Character`, `String` |
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| Big numeric types | `BigInteger`, `BigDecimal` |
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| Time related types | `LocalTime`, `LocalDate`, `LocalDateTime`, `Instant` |
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| Utility types | `UUID`, `File`, `Path`, `URL`, `URI` |
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| Enums | Any Java enum |
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| Configurations | Any Java record or any class annotated with `@Configuration` |
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| `ConfigurationSerializable` | All Bukkit classes that implement this interface, like `ItemStack` |
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| Collections | (Nested) Lists, sets, maps*, or arrays of previously listed types |
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(*) Map keys can only be of simple or enum type, i.e. they cannot be in
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the `Collections`, `Configurations`, or `ConfigurationSerializable` type class.
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For all types that are not listed in the table above, you can provide your
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own [custom serializer](#custom-serializers).
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#### Examples of supported types
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The following class contains examples of types that this library supports:
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```java
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public final class SupportedTypes {
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boolean supported;
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Character supported;
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String supported;
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LocalTime supported;
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UUID supported;
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ExampleEnum supported; // where 'ExampleEnum' is some Java enum type
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ExampleConfig supported; // where 'ExampleConfig' is a class annotated with @Configuration
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ExampleRecord supported; // where 'ExampleRecord' is a Java record
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/* collection types */
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List<BigInteger> supported;
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Set<Double> supported;
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LocalDate[] supported;
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Map<ExampleEnum, ExampleConfig> supported;
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/* nested collection types */
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List<Map<ExampleEnum, LocalDate>> supported;
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int[][] supported;
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Map<Integer, List<Map<Short, Set<ExampleRecord>>>> supported;
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// supported if a custom serializer is registered
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java.awt.Point supported;
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// supported when a special properties object is used (explained further below)
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org.bukkit.inventory.ItemStack supported;
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}
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```
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<details>
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<summary>Examples of unsupported types</summary>
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The following class contains examples of types that this library does (and will)
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not support:
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```java
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public final class UnsupportedTypes<T> {
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Map<Point, String> unsupported; // invalid map key
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Map<List<String>, String> unsupported; // invalid map key
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Box<String> unsupported; // custom parameterized type
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List<? extends String> unsupported; // wildcard type
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List<?> unsupported; // wildcard type
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List<?>[] unsupported; // wildcard type
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T unsupported; // type variable
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List unsupported; // raw type
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List[] unsupported; // raw type
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List<String>[] unsupported; // generic array type
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Set<Integer>[] unsupported; // generic array type
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Map<Byte, Byte>[] unsupported; // generic array type
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}
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```
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**NOTE:** Even though this library does not support these types, it is still
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possible to serialize them by providing a custom serializer via
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the [`@SerializeWith`](#the-serializewith-annotation) annotation. That
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serializer then has to be applied to top-level type (i.e. `nesting` must be set
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to `0`, which is the default).
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</details>
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### Loading and saving configurations
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There are two ways to load and save configurations. Which way you choose depends
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on your liking. Both ways have five methods in common:
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* The `save` method converts a configuration to a string in YAML format and
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saves that string to a file. The file is created if it does not exist and is
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overwritten otherwise.
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* The `load` method creates a new configuration instance and populates it with
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values taken from a file. For classes, the no-args constructor is used to
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create a new instance. For records, the canonical constructor is called.
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* The `update` method is a combination of `load` and `save` and the method you'd
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usually want to use: it takes care of creating the configuration file if it
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does not exist and otherwise updates it to reflect changes to (the
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configuration elements of) the configuration type.
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* The `write` method works the same way as the `save` method but writes the
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string to a `java.io.OutputStream`.
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* The `read` method works the same way as the `load` method but reads the values
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from a `java.io.InputStream`.
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<details>
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<summary>Example of <code>update</code> behavior when configuration file exists</summary>
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Let's say you have the following configuration type
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```java
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@Configuration
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public final class C {
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int i = 10;
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int j = 11;
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}
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```
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... and a YAML configuration file that contains:
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```yaml
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i: 20
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k: 30
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```
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Now, when you call the `update` method for that configuration type and file
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using any of the two options listed below, the configuration instance
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that `update` returns will have its `i` variable initialized to `20` and its `j`
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variable will have its default of `11`. After the operation, the configuration
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file will contain the following content (note that `k` has been dropped):
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```yaml
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i: 20
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j: 11
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```
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<hr>
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</details>
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To exemplify the usage of these five methods we assume for the following
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sections that you have implemented the configuration type below and have access
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to some regular `java.nio.file.Path` object `configurationFile`.
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```java
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@Configuration
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public final class Config { /* some fields */ }
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```
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#### Option 1
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The first option is to create a `YamlConfigurationStore` instance and use it to
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save, load, or update configurations.
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```java
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YamlConfigurationProperties properties = YamlConfigurationProperties.newBuilder().build();
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YamlConfigurationStore<Config> store = new YamlConfigurationStore<>(Config.class, properties);
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Config config1 = store.load(configurationFile);
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store.save(config1, configurationFile);
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Config config2 = store.update(configurationFile);
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```
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Using a `YamlConfigurationStore` directly is always more efficient than the
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second option show below, especially if you are calling any of its method
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multiple times.
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#### Option 2
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The second option is to use the static methods from the `YamlConfigurations`
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class.
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```java
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Config config1 = YamlConfigurations.load(configurationFile, Config.class);
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YamlConfigurations.save(configurationFile, Config.class, config1);
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Config config2 = YamlConfigurations.update(configurationFile, Config.class);
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```
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Each of these methods has two additional overloads: One that takes a properties
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object and another that lets you configure a properties object builder. For
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example, the overloads of the `load` method are:
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```java
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// overload 1
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YamlConfigurationProperties properties = YamlConfigurationProperties.newBuilder().build();
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Config config1 = YamlConfigurations.load(configurationFile, Config.class, properties);
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// overload 2
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Config config2 = YamlConfigurations.load(
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configurationFile,
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Config.class,
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builder -> builder.inputNulls(true).outputNulls(false)
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);
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```
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<hr>
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All five methods can also be passed a Java record instead of a class. To provide
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default values for records when calling the `update` method, you can add a
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constructor with no parameters that initializes its components. This constructor
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is only called if the configuration file does not exist.
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```java
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record User(String name, String email) {
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User() { this("John Doe", "john@doe.com"); }
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}
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User user = YamlConfigurations.update(configurationFile, User.class);
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```
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### Configuration properties
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Instances of the `ConfigurationProperties` class allow customization of how
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configurations are stored and loaded. To create such an instance, instantiate a
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new builder using the `YamlConfigurationProperties.newBuilder()` method,
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configure it, and finally call its `build()` method. Alternatively, you can use
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the `toBuilder()` method of an existing `YamlConfigurationProperties` to create
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a new builder that is initialized with values takes from the properties object.
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Check out the methods of the builder class to see which configuration options
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are available.
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#### Support for Bukkit classes like `ItemStack`
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There is a special `YamlConfigurationProperties` object with
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name `BUKKIT_DEFAULT_PROPERTIES` that adds support for
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Bukkit's `ConfigurationSerializable` types. If you want to use any of these
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types in your configuration, you have to use that object as a starting point:
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```java
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YamlConfigurationProperties properties = ConfigLib.BUKKIT_DEFAULT_PROPERTIES.toBuilder()
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// ...further configure the builder...
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.build();
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```
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To get access to this object, you have to import `configlib-paper` instead
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of `configlib-yaml` as described in the [Import](#import) section.
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### Comments
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The configuration elements of a configuration type can be annotated with
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the `@Comment` annotation. This annotation takes an array of strings. Each of
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these strings is written onto a new line as a comment. The strings can
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contain `\n` characters. Empty strings are written as newlines (not as
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comments).
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If a configuration type _C_ that defines comments is used (as a configuration
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element) within another configuration type, the comments of _C_ are written with
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the proper indentation. However, if instances of _C_ are stored inside a
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collection, their comments are not printed when the collection is written.
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Serializing the following configuration as YAML ...
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```java
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@Configuration
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public final class ExampleConfiguration {
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@Comment({"Hello", "", " ", "World"})
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private String commentedField = "commented field";
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}
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```
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... results in the YAML file shown below:
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```yaml
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# Hello
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#
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# World
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commentedField: commented field
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```
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Similarly, if you define the following record configuration and save it ...
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```java
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record Address(@Comment("The street") String street) {}
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record User(@Comment("The name") String name, @Comment("The address") Address address) {}
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User user = new User("John Doe", new Address("10 Downing St"));
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```
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... you get:
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```yaml
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# The name
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name: John Doe
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# The address
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address:
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# The street
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street: 10 Downing St
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```
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### Subclassing
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Subclassing of configurations types is supported. Subclasses of configuration
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types don't need to be annotated with `@Configuration`. When a configuration is
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written, the fields of parent classes are written before the fields of the child
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in a top to bottom manner. Parent configurations can be `abstract`.
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#### Shadowing of fields
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Shadowing of fields refers to the situation where a subclass of configuration
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has a field that has the same name as a field in one of its super classes.
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Shadowing of fields is currently not supported. (This restriction might easily
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be lifted. If you need this feature, please open an issue and describe how to
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handle name clashes.)
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### Ignoring and filtering fields
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Fields that are `final`, `static`, `transient` or annotated with `@Ignore` are
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neither serialized nor updated during deserialization. You can filter out
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additional fields by providing an instance of `FieldFilter` to the configuration
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properties. Record components cannot be filtered.
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### Handling of missing and `null` values
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#### Missing values
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When a configuration file is read, values that correspond to a configuration
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element might be missing. That can happen, for example, when somebody deleted
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that value from the configuration file, when you add configuration elements to
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your configuration type, or when the `NameFormatter` that was used to create
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that file is replaced.
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In such cases, fields of configuration classes keep the default value you
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assigned to them and record components are initialized with the default value of
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their corresponding type.
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#### Null values
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**NOTE:** Null values written to a configuration file generally don't give any
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indication about which kinds of values the configuration expects. Therefore,
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they not only make it harder for the users of that configuration file to
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properly configure it, but they might also prevent loading a configuration if
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the values the users set are of the wrong type.
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Although strongly discouraged, null values are supported
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and `ConfigurationProperties` let you configure how they are handled when
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serializing and deserializing a configuration:
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* By setting `outputNulls` to false, configuration elements, and collection
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elements that are null are not output. Any comments that belong to such fields
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are also not written.
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* By setting `inputNulls` to false, null values read from the configuration file
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are treated as missing and are, therefore, handled as described in the section
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above.
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* By setting `inputNulls` to true, null values read from the configuration file
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override the corresponding default values of a configuration class with null
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or set the component value of a record type to null. If the configuration
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element type is primitive, an exception is thrown.
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The following code forbids null values to be output but allows null values to be
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input. By default, both are forbidden which makes the call to `outputNulls` in
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this case redundant.
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```java
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YamlConfigurationProperties.newBuilder()
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.outputNulls(false)
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.inputNulls(true)
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.build();
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```
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### Formatting the names of configuration elements
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You can define how the names of configuration elements are formatted by
|
|
configuring the configuration properties with a custom formatter. Formatters are
|
|
implementations of the `NameFormatter` interface. You can implement this
|
|
interface yourself or use one of the several formatters this library provides.
|
|
These pre-defined formatters can be found in the `NameFormatters` class.
|
|
|
|
The following code formats fields using the `IDENTITY` formatter (which is the
|
|
default).
|
|
|
|
```java
|
|
YamlConfigurationProperties.newBuilder()
|
|
.setNameFormatter(NameFormatters.IDENTITY)
|
|
.build();
|
|
```
|
|
|
|
### Type conversion and serializer selection
|
|
|
|
Before instances of the types listed in the [supported types](#supported-types)
|
|
section can be stored, they need to be converted into serializable types (i.e.
|
|
into types the underlying YAML library knows how to handle). The conversion
|
|
happens according to the following table:
|
|
|
|
| Source type | Target type |
|
|
|-----------------------------|------------------|
|
|
| Boolean types | `Boolean` |
|
|
| Integer types | `Long` |
|
|
| Floating point types | `Double` |
|
|
| Characters and strings | `String` |
|
|
| Big numeric types | `String` |
|
|
| Time related types | `String` |
|
|
| Utility types | `String` |
|
|
| Enums | `String` |
|
|
| Configurations | `Map<String, ?>` |
|
|
| `Set<S>` | `List<T>` |
|
|
| `List<S>` | `List<T>` |
|
|
| `S[]` | `List<T>` |
|
|
| `Map<S1, S2>` | `Map<T1, T2>` |
|
|
| `ConfigurationSerializable` | `String` |
|
|
|
|
#### Serializer selection
|
|
|
|
To convert the value of a configuration element `E` with (source) type `S` into
|
|
a serializable value of some target type, a serializer has to be selected.
|
|
Serializers are instances of the `de.exlll.configlib.Serializer` interface and
|
|
are selected based on `S`. Put differently, serializers are, by default, always
|
|
selected based on the compile-time type of `E` and never on the runtime type of
|
|
its value.
|
|
|
|
<details>
|
|
<summary>Why should I care about this?</summary>
|
|
|
|
This distinction makes a difference (and might lead to confusion) when you have
|
|
configuration elements that are configuration classes, and you extend those
|
|
classes. Concretely, assume you have written two configuration classes `A`
|
|
and `B` where `B extends A`. Then, if you use `A a = new B()` in your main
|
|
configuration, only the fields of a `A` will be stored when you save your main
|
|
configuration. That is because the serializer of field `a` was selected based on
|
|
the compile-time type of `a` which is `A` and not `B`. The same happens if you
|
|
have a `List<A>` and put instances of `B` (or some other subclass of `A`) in it.
|
|
|
|
If you need such behavior, have a look at
|
|
the [`@Polymorphic`](#the-polymorphic-annotation) annotation.
|
|
|
|
</details>
|
|
|
|
<details>
|
|
<summary>Order of serializer selection</summary>
|
|
|
|
You can override the default selection by annotating a configuration
|
|
element with [`@SerializeWith`](#the-serializewith-annotation), by annotating a
|
|
type with `@SerializeWith`, or by adding your own serializer for `S` to the
|
|
configuration properties. When you do so, it can happen that there multiple
|
|
serializers available for a particular configuration element and its type. In
|
|
that case, one of them chosen according to the following precedence rules:
|
|
|
|
1. If the element is annotated with `@SerializeWith` and the `nesting` matches,
|
|
the serializer referenced by the annotation is selected.
|
|
2. Otherwise, if the `ConfigurationProperties` contain a serializer for the type
|
|
in question, that serializer is returned.
|
|
* Serializers created by factories that were added
|
|
through `addSerializerFactory` for some type take precedence over
|
|
serializers added by `addSerializer` for the same type.
|
|
3. If the type is annotated `@SerializeWith`, the serializer referenced by the
|
|
annotation is selected.
|
|
4. If the type is annotated with an annotation which is annotated
|
|
with `@SerializeWith`, the serializer referenced by `@SerializeWith` is
|
|
returned.
|
|
5. If this library defines a serializer for that type, that serializer is
|
|
selected.
|
|
6. Ultimately, if no serializer can be found, an exception is thrown.
|
|
|
|
For lists, sets, and maps, the algorithm is applied to their generic type
|
|
arguments recursively first.
|
|
|
|
</details>
|
|
|
|
##### The `@SerializeWith` annotation
|
|
|
|
The `@SerializeWith` annotation enforces the use of the specified serializer for
|
|
a configuration element or type. It can be applied to configuration elements
|
|
(i.e. class fields and record components), to types, and to other annotations.
|
|
|
|
```java
|
|
@SerializeWith(serializer = MyPointSerializer.class)
|
|
Point point;
|
|
```
|
|
|
|
```java
|
|
@SerializeWith(serializer = SomeClassSerializer.class)
|
|
public final class SomeClass {/* ... */}
|
|
```
|
|
|
|
The serializer referenced by this annotation is selected regardless of whether
|
|
the annotated type or type of configuration element matches the type the
|
|
serializer expects.
|
|
|
|
If the annotation is applied to a configuration element and that element is an
|
|
array, list, set, or map, a nesting level can be set to apply the serializer not
|
|
to the top-level type but to its elements. For maps, the serializer is applied
|
|
to the values and not the keys.
|
|
|
|
```java
|
|
@SerializeWith(serializer = MySetSerializer.class, nesting = 1)
|
|
List<Set<String>> list;
|
|
```
|
|
|
|
Setting `nesting` to an invalid value, i.e. a negative one or one that is
|
|
greater than the number of levels the element actually has, results in the
|
|
serializer not being selected. For type annotations, the `nesting` has no
|
|
effect.
|
|
|
|
<details>
|
|
<summary>More <code>nesting</code> examples</summary>
|
|
|
|
In this example...
|
|
|
|
```java
|
|
@SerializeWith(serializer = MySetSerializer.class, nesting = 1)
|
|
List<Set<String>> list;
|
|
```
|
|
|
|
* a nesting of `0` would apply the serializer to `list` (which is of
|
|
type `List<Set<String>>`),
|
|
* a nesting of `1` would apply it to the `Set<String>` elements within `list`,
|
|
and
|
|
* a nesting of `2` would apply it to the strings within the sets of `list`.
|
|
|
|
However, since the referenced serializer `MySetSerializer` most likely
|
|
expects `Set`s as input, setting `nesting` to `0` or `2` would result in an
|
|
exception being thrown when the configuration is serialized.
|
|
|
|
Some more examples:
|
|
|
|
```java
|
|
// MyListSerializer is applied to 'list'
|
|
@SerializeWith(serializer = MyListSerializer.class)
|
|
List<Set<String>> list;
|
|
|
|
// MySetSerializer is applied to the Set<String> elements of 'list'
|
|
@SerializeWith(serializer = MySetSerializer.class, nesting = 1)
|
|
List<Set<String>> list;
|
|
|
|
// MyStringSerializer is applied to the strings within the set elements of 'list'
|
|
@SerializeWith(serializer = MyStringSerializer.class, nesting = 2)
|
|
List<Set<String>> list;
|
|
|
|
// MyMap0Serializer is applied to 'map'
|
|
@SerializeWith(serializer = MyMap0Serializer.class)
|
|
Map<Integer, Map<String, Double>> map;
|
|
|
|
// MyMap1Serializer is applied to the Map<String, Double> values of 'map'
|
|
@SerializeWith(serializer = MyMap1Serializer.class, nesting = 1)
|
|
Map<Integer, Map<String, Double>> map;
|
|
|
|
// MyDoubleSerializer is applied to the doubles within the nested values of 'map'
|
|
@SerializeWith(serializer = MyDoubleSerializer.class, nesting = 2)
|
|
Map<Integer, Map<String, Double>> map;
|
|
```
|
|
|
|
</details>
|
|
|
|
#### The `@Polymorphic` annotation
|
|
|
|
The `@Polymorphic` annotation indicates that the annotated type is polymorphic.
|
|
Serializers for polymorphic types are not selected based on the compile-time
|
|
types of configuration elements, but instead are chosen at runtime based on the
|
|
actual types of their values.
|
|
|
|
This enables adding instances of subclasses / implementations of a polymorphic
|
|
type to collections. The subtypes must be valid configurations.
|
|
|
|
```java
|
|
@Polymorphic
|
|
@Configuration
|
|
static abstract class A { ... }
|
|
|
|
static final class Impl1 extends A { ... }
|
|
static final class Impl2 extends A { ... }
|
|
|
|
List<A> as = List.of(new Impl1(...), new Impl2(...), ...);
|
|
```
|
|
|
|
For correct deserialization, if an instance of polymorphic type (or one of its
|
|
implementations / subclasses) is serialized, an additional property that holds
|
|
type information is added to its serialization. By default, that type
|
|
information is the Java class name of the actual type. It is possible to provide
|
|
type aliases by using the `PolymorphicTypes` annotation.
|
|
|
|
```java
|
|
@Polymorphic
|
|
@PolymorphicTypes({
|
|
@PolymorphicTypes.Type(type = Impl1.class, alias = "IMPL_1"),
|
|
@PolymorphicTypes.Type(type = Impl2.class, alias = "IMPL_2")
|
|
})
|
|
interface B { ... }
|
|
|
|
record Impl1(...) implements B { ... }
|
|
record Impl2(...) implements B { ... }
|
|
```
|
|
|
|
### Custom serializers
|
|
|
|
If you want to add support for a type that is not a Java record or whose class
|
|
is not annotated with `@Configuration`, or if you don't like how one of the
|
|
supported types is serialized by default, you can write your own custom
|
|
serializer.
|
|
|
|
Serializers are instances of the `de.exlll.configlib.Serializer` interface. When
|
|
implementing that interface you have to make sure that you convert your source
|
|
type into one of the valid target types listed
|
|
in [type conversion](#type-conversion-and-serializer-selection) section.
|
|
|
|
The serializer then has to be registered through a `ConfigurationProperties`
|
|
object or alternatively be applied to a configuration element or type
|
|
with [`@SerializeWith`](#the-serializewith-annotation). If you want to use
|
|
the `@SerializeWith` annotation, your serializer class must either have a
|
|
constructor with no parameters or one with exactly one parameter of
|
|
type [`SerializerContext`](#the-serializercontext-interface).
|
|
|
|
The following `Serializer` serializes instances of `java.awt.Point` into strings
|
|
and vice versa.
|
|
|
|
```java
|
|
public final class PointSerializer implements Serializer<Point, String> {
|
|
@Override
|
|
public String serialize(Point element) {
|
|
return element.x + ":" + element.y;
|
|
}
|
|
|
|
@Override
|
|
public Point deserialize(String element) {
|
|
String[] parts = element.split(":");
|
|
int x = Integer.parseInt(parts[0]);
|
|
int y = Integer.parseInt(parts[1]);
|
|
return new Point(x, y);
|
|
}
|
|
}
|
|
```
|
|
|
|
```java
|
|
YamlConfigurationProperties properties = YamlConfigurationProperties.newBuilder()
|
|
.addSerializer(Point.class, new PointSerializer())
|
|
.build();
|
|
```
|
|
|
|
##### The `SerializerContext` interface
|
|
|
|
Instances of the `SerializerContext` interface contain contextual information
|
|
for custom serializers. A context object gives access to the configuration
|
|
properties, configuration element, and the annotated type for which the
|
|
serializer was selected.
|
|
|
|
Context objects can be obtained when adding serializer factories through
|
|
the `addSerializerFactory` method:
|
|
|
|
```java
|
|
public final class PointSerializer implements Serializer<Point, String> {
|
|
private final SerializerContext context;
|
|
|
|
public PointSerializer(SerializerContext context) {
|
|
this.context = context;
|
|
}
|
|
// implementation ...
|
|
}
|
|
```
|
|
|
|
```java
|
|
YamlConfigurationProperties properties = YamlConfigurationProperties.newBuilder()
|
|
.addSerializerFactory(Point.class, PointSerializer::new)
|
|
.build();
|
|
```
|
|
|
|
Custom serializers used with `@SerializeWith` are allowed to declare a
|
|
constructor with one parameter of type `SerializerContext`. If such a
|
|
constructor exists, a context object is passed to it when the serializer is
|
|
instantiated by this library.
|
|
|
|
### Changing the type of configuration elements
|
|
|
|
Changing the type of configuration elements is not supported. If you change the
|
|
type of one of these but your configuration file still contains a value of the
|
|
old type, a type mismatch will occur when loading a configuration from that
|
|
file. Instead, remove the old element and add a new one with a different name.
|
|
|
|
### Recursive type definitions
|
|
|
|
Recursive type definitions are currently not allowed but might be supported in a
|
|
future version if this feature is requested.
|
|
|
|
<details>
|
|
<summary>Examples of recursive type definitions</summary>
|
|
|
|
Neither direct nor indirect recursive type definitions are supported.
|
|
|
|
```java
|
|
public final class RecursiveTypDefinitions {
|
|
// Direct recursive definition
|
|
@Configuration
|
|
static final class R {
|
|
R r;
|
|
}
|
|
|
|
// Indirect recursive definition
|
|
@Configuration
|
|
static final class R1 {
|
|
R2 r2;
|
|
}
|
|
|
|
@Configuration
|
|
static final class R2 {
|
|
R1 r1;
|
|
}
|
|
}
|
|
```
|
|
|
|
</details>
|
|
|
|
## Project and repository structure
|
|
|
|
This project contains three classes of modules:
|
|
|
|
* The `configlib-core` module contains most of the logic of this library. In it,
|
|
you can find (among other things), the object mapper that converts
|
|
configuration instances to maps (and vice versa), most serializers, and the
|
|
classes responsible for the extraction of comments. It does not contain
|
|
anything Minecraft related.
|
|
* The `configlib-yaml` module contains the classes that can save configuration
|
|
instances as YAML files and instantiate new instances from such files. This
|
|
module does not contain anything Minecraft related, either.
|
|
* The `configlib-paper`, `configlib-velocity`, and `configlib-waterfall` modules
|
|
contain basic plugins that are used to conveniently load this library. These
|
|
three modules shade the `-core` module, the `-yaml` module, and the YAML
|
|
parser when the `shadowJar` task is executed. The shaded jar files are
|
|
released on the [releases page](https://github.com/Exlll/ConfigLib/releases).
|
|
* The `configlib-paper` module additionally contains
|
|
the `ConfigLib.BUKKIT_DEFAULT_PROPERTIES` object which adds support for
|
|
the serialization of Bukkit classes like `ItemStack` as
|
|
described [here](#support-for-bukkit-classes-like-itemstack).
|
|
|
|
The GitHub repository of this project uses two branches:
|
|
|
|
* The `master` branch contains the functionality of the latest release version.
|
|
* The `dev` branch contains the newest, possibly unstable features and
|
|
refactorings.
|
|
|
|
**If you plan to contribute to this project, please base your commits on
|
|
the `dev` branch.**
|
|
|
|
## Import
|
|
|
|
To use this library, import it into your project with Maven or Gradle. Examples
|
|
of how to do that are at the end of this section within the spoilers. Currently,
|
|
there are two repositories from which you can
|
|
choose: [jitpack.io](https://jitpack.io/#Exlll/ConfigLib) and GitHub (which
|
|
requires authentication, see
|
|
this [issue](https://github.com/Exlll/ConfigLib/issues/12) if you have any
|
|
problems).
|
|
|
|
This library has additional dependencies (namely, a YAML parser) which are not
|
|
exposed by the artifact you import. You can download _plugin versions_ of this
|
|
library that bundle all its dependencies. The artifacts of these versions can be
|
|
found on the [releases page](https://github.com/Exlll/ConfigLib/releases) where
|
|
you can identify them by their `-paper-`, `-waterfall-`, and `-velocity-` infix
|
|
and `-all` suffix. Except for the `-paper-` version, the other plugin versions
|
|
currently do not add any additional features. A benefit of these versions is
|
|
that they make it easier for you to update this library if you have written
|
|
multiple plugins that use it. If you plan to use these versions, don't forget to
|
|
add the plugin as a dependency to the `plugin.yml` (for Paper and Waterfall) or
|
|
to the dependencies array (for Velocity) of your own plugin.
|
|
|
|
Alternatively, if you don't want to use an extra plugin, you can shade
|
|
the `-yaml` version with its YAML parser yourself.
|
|
|
|
### Import examples
|
|
|
|
If you want serialization support for Bukkit classes like `ItemStack`,
|
|
replace `configlib-yaml` with `configlib-paper`
|
|
(see [here](#support-for-bukkit-classes-like-itemstack)).
|
|
|
|
<details>
|
|
<summary>
|
|
Import via <a href="https://jitpack.io/#Exlll/ConfigLib">jitpack.io</a>
|
|
</summary>
|
|
|
|
**Maven**
|
|
|
|
```xml
|
|
<repository>
|
|
<id>jitpack.io</id>
|
|
<url>https://jitpack.io</url>
|
|
</repository>
|
|
|
|
<dependency>
|
|
<groupId>com.github.Exlll.ConfigLib</groupId>
|
|
<artifactId>configlib-yaml</artifactId>
|
|
<version>v4.4.0</version>
|
|
</dependency>
|
|
```
|
|
|
|
**Gradle**
|
|
|
|
```groovy
|
|
repositories { maven { url 'https://jitpack.io' } }
|
|
|
|
dependencies { implementation 'com.github.Exlll.ConfigLib:configlib-yaml:v4.4.0' }
|
|
```
|
|
|
|
```kotlin
|
|
repositories { maven { url = uri("https://jitpack.io") } }
|
|
|
|
dependencies { implementation("com.github.Exlll.ConfigLib:configlib-yaml:v4.4.0") }
|
|
```
|
|
|
|
</details>
|
|
|
|
<details>
|
|
<summary>
|
|
Import via GitHub
|
|
</summary>
|
|
|
|
Importing via GitHub requires authentication. Check
|
|
this [issue](https://github.com/Exlll/ConfigLib/issues/12) if you have any
|
|
trouble with that.
|
|
|
|
**Maven**
|
|
|
|
```xml
|
|
<repository>
|
|
<id>de.exlll</id>
|
|
<url>https://maven.pkg.github.com/Exlll/ConfigLib</url>
|
|
</repository>
|
|
|
|
<dependency>
|
|
<groupId>de.exlll</groupId>
|
|
<artifactId>configlib-yaml</artifactId>
|
|
<version>4.4.0</version>
|
|
</dependency>
|
|
```
|
|
|
|
**Gradle**
|
|
|
|
```groovy
|
|
repositories { maven { url 'https://maven.pkg.github.com/Exlll/ConfigLib' } }
|
|
|
|
dependencies { implementation 'de.exlll:configlib-yaml:4.4.0' }
|
|
```
|
|
|
|
```kotlin
|
|
repositories { maven { url = uri("https://maven.pkg.github.com/Exlll/ConfigLib") } }
|
|
|
|
dependencies { implementation("de.exlll:configlib-yaml:4.4.0") }
|
|
```
|
|
|
|
</details>
|
|
|
|
## Future work
|
|
|
|
This section contains ideas for upcoming features. If you want any of these to
|
|
happen any time soon,
|
|
please [open an issue](https://github.com/Exlll/ConfigLib/issues/new) where we
|
|
can discuss the details.
|
|
|
|
- JSON, TOML, XML support
|
|
- Post-load/Pre-save hooks
|
|
- More features and control over updating/versioning
|
|
- More control over the ordering of fields, especially in parent/child class
|
|
scenarios
|
|
- Recursive definitions
|
|
- Shadowing of fields
|