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936 lines
36 KiB
Markdown
# ConfigLib
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**A Minecraft library for saving, loading, updating, and commenting YAML configuration files.**
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This library facilitates creating, saving, loading, updating, and commenting YAML configuration
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files. It does so by automatically mapping instances of configuration classes to serializable maps
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which are first transformed into YAML 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 this documentation.
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For a step-by-step tutorial that shows most features of this library in action check out
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the [Tutorial](https://github.com/Exlll/ConfigLib/wiki/Tutorial) page on the 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 of features is
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discussed in the following sections. Information on how to [import](#import) this library is located
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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 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 at `/tmp/config.yml`. Its content
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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 because null values
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are not output by default. That behavior can be changed by the builder.
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2. The password of the user with username `user3` has no comment. This is due to limitations of
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the YAML library. Configurations in lists, sets, or maps 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 record type or to any
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non-generic class that is directly or indirectly (i.e. through subclassing) annotated with
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`@de.exlll.configlib.Configuration`. Accordingly, the term _configuration_ refers to an instance of
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such a type. A _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 no-args constructor can
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be `private`. Inner classes (i.e. the ones that are nested but not `static`) have an implicit
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synthetic constructor with at least 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 any of the supported
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types listed in the next section. You can (and should) initialize all fields of a configuration
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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 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 the `Collections`,
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`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) 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 possible to serialize
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them by providing a custom serializer via the [`@SerializeWith`](#the-serializewith-annotation)
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annotation. That 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 on your liking.
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Both ways have three methods in common:
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* The `save` method saves a configuration to a file. The file is created if it does not exist and
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is overwritten otherwise.
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* The `load` method creates a new configuration instance and populates it with values taken from a
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file. For classes, the no-args constructor is used to create a new instance. For records, the
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canonical constructor is called.
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* The `update` method is a combination of `load` and `save` and the method you'd usually want to
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use: it takes care of creating the configuration file if it does not exist and otherwise updates
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it to reflect changes to (the configuration elements of) the configuration type.
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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 use one of the methods below to call `update` for that configuration type and file,
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the configuration instance that `update` returns will have its `i` variable initialized to `20`
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and its `j` variable will have its default of `11`. After the operation, the configuration file will
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contain:
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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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</details>
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To exemplify the usage of these three methods we assume for the following sections that you have
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implemented the configuration type below and have access to some regular `java.nio.file.Path`
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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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#### Way 1
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The first way is to create a configuration store and use it directly to save, load, or update
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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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#### Way 2
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The second way is to use the static methods from the `YamlConfigurations` 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 object and another
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that lets you configure a properties object builder. For example, the overloads of the `load`
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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 three methods can also be passed a Java record instead of a class. To provide default values
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for records when calling the `update` method, you can add a constructor with no parameters that
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initializes its components. This constructor is only called if the configuration file does not
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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 configurations are
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stored and loaded. To create such an instance, instantiate a new builder using
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the `YamlConfigurationProperties.newBuilder()` method, configure it, and finally call its `build()`
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method. Alternatively, you can use the `toBuilder()` method of an
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existing `YamlConfigurationProperties` to create a new builder that is initialized with values
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takes from the properties object.
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Check out the methods of the builder class to see which configuration options are available.
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#### Support for Bukkit classes like `ItemStack`
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There is a special `YamlConfigurationProperties` object with name `BUKKIT_DEFAULT_PROPERTIES`
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that adds support for 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 of `configlib-yaml` as
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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 the `@Comment` annotation.
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This annotation takes an array of strings. Each of these strings is written onto a new line as a
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comment. The strings can 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 element) within
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another configuration type, the comments of _C_ are written with the proper indentation. However, if
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instances of _C_ are stored inside a collection, their comments are not printed when the collection
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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 types don't need to be
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annotated with `@Configuration`. When a configuration is written, the fields of parent classes
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are written before the fields of the child in a top to bottom manner. Parent configurations can
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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 has a field that has
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the same name as a field in one of its super classes. Shadowing of fields is currently not
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supported. (This restriction might easily be lifted. If you need this feature, please open an issue
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and describe how to 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 neither serialized
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nor updated during deserialization. You can filter out additional fields by providing an instance of
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`FieldFilter` to the configuration 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 element might be
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missing. That can happen, for example, when somebody deleted that value from the configuration file,
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when you add configuration elements to your configuration type, or when the `NameFormatter` that
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was used to create that file is replaced.
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In such cases, fields of configuration classes keep the default value you assigned to them and
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record components are initialized with the default value of 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 indication about
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which kinds of values the configuration expects. Therefore, they not only make it harder for the
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users of that configuration file to properly configure it, but they might also prevent loading a
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configuration if the values the users set are of the wrong type.
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Although strongly discouraged, null values are supported and `ConfigurationProperties` let you
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configure how they are handled when serializing and deserializing a configuration:
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* By setting `outputNulls` to false, configuration elements, and collection elements that
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are null are not output. Any comments that belong to such fields are also not written.
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* By setting `inputNulls` to false, null values read from the configuration file are treated as
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missing and are, therefore, handled as described in the section above.
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* By setting `inputNulls` to true, null values read from the configuration file override the
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corresponding default values of a configuration class with null or set the component value of a
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record type to null. If the configuration 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 input. By default,
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both are forbidden which makes the call to `outputNulls` in 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
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configuration properties with a custom formatter. Formatters are implementations of
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the `NameFormatter` interface. You can implement this interface yourself or use one of the several
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formatters this library provides. These pre-defined formatters can be found in the `NameFormatters`
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class.
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The following code formats fields using the `IDENTITY` formatter (which is the default).
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```java
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YamlConfigurationProperties.newBuilder()
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.setNameFormatter(NameFormatters.IDENTITY)
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.build();
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```
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### Type conversion and serializer selection
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Before instances of the types listed in the [supported types](#supported-types) section can be
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stored, they need to be converted into serializable types (i.e. into types the underlying YAML
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library knows how to handle). The conversion happens according to the following table:
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| Source type | Target type |
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|-----------------------------|------------------|
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| Boolean types | `Boolean` |
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| Integer types | `Long` |
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| Floating point types | `Double` |
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| Characters and strings | `String` |
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| 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` |
|
|
|
|
(*) By default, sets are serialized as lists. This can be changed through the configuration
|
|
properties. This also means that `Set`s are valid target types.
|
|
|
|
#### 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.
|
|
|
|
</details>
|
|
|
|
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.
|
|
|
|
##### 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>v4.2.0</version>
|
|
</dependency>
|
|
```
|
|
|
|
**Gradle**
|
|
|
|
```groovy
|
|
repositories { maven { url 'https://jitpack.io' } }
|
|
|
|
dependencies { implementation 'com.github.Exlll.ConfigLib:configlib-yaml:v4.2.0' }
|
|
```
|
|
|
|
```kotlin
|
|
repositories { maven { url = uri("https://jitpack.io") } }
|
|
|
|
dependencies { implementation("com.github.Exlll.ConfigLib:configlib-yaml:v4.2.0") }
|
|
```
|
|
|
|
</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>4.2.0</version>
|
|
</dependency>
|
|
```
|
|
|
|
**Gradle**
|
|
|
|
```groovy
|
|
repositories { maven { url 'https://maven.pkg.github.com/Exlll/ConfigLib' } }
|
|
|
|
dependencies { implementation 'de.exlll:configlib-yaml:4.2.0' }
|
|
```
|
|
|
|
```kotlin
|
|
repositories { maven { url = uri("https://maven.pkg.github.com/Exlll/ConfigLib") } }
|
|
|
|
dependencies { implementation("de.exlll:configlib-yaml:4.2.0") }
|
|
```
|
|
|
|
</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
|