ConfigLib

This library facilitates creating, saving and loading YAML configuration files. It does so by using Reflection on configuration classes and automatically saving and loading their fields, creating the configuration file and its parent directories if necessary.

Features

• automatic creation, saving and loading of YAML configurations
• automatic creation of parent directories
• option to add explanatory comments by adding annotations to the class and its fields
• option to exclude fields by making them final, static or transient

General information

Default and null values

All reference type fields of a configuration class must be assigned non-null default values. If a value is null while saving takes place, a NullPointerException will be thrown.

Serialization of custom classes

You can add fields to your configuration class whose type is some custom class. To be properly serialized, the fields of the custom class need to be either public or have getter and setter methods. @Comments added to the custom class are ignored and won't be displayed in the configuration file.

How-to

Creating a configuration

To create a new configuration, create a class which extends Configuration. Fields which are added to this class and which are not final, static or transient can automatically be saved to the corresponding configuration file.

Saving and loading a configuration

Instances of your configuration class have a load, save and loadAndSave method:

• load updates all fields of an instance with the values read from the configuration file.
• save dumps all field names and values to a configuration file. If the file exists, it is overridden; otherwise, it is created.
• loadAndSave first calls load and then save, which is useful when you have added or removed fields from the class or you simply don't know if the configuration file exists.

Adding and removing fields

In order to add or to remove fields, you just need to add them to or remove them from your configuration class. The changes are saved to the configuration file the next time save or loadAndSave is called.

Post load action

You can override postLoadHook to execute some action after the configuration has successfully been loaded.

Comments

By using the @Comment annotation, you can add comments to your configuration file. The annotation can be applied to classes or fields. Each String of the passed array is written into a new line.

Examples

Example of a custom class

public class Custom {
    public String publicString = "public";    // doesn't need any additional methods to be saved
    private String privateString = "private"; // needs additional getter and setter methods

    public String getPrivateString() {
        return privateString;
    }
    public void setPrivateString(String privateString) {
        this.privateString = privateString;
    }
}

Example database configuration

import de.exlll.configlib.Comment;
import de.exlll.configlib.Configuration;
/* other imports */

@Comment({
        "This is a multiline comment.",
        "It describes what the configuration is about."
})
public final class DatabaseConfig extends Configuration {
    /* ignored fields */
    private final String ignored1 = "";     // ignored because final
    private static String ignored2 = "";    // ignored because static
    private transient String ignored3 = ""; // ignored because transient
    /* included fields */
    private String host = "localhost";
    private int port = 3306;
    @Comment("This is a single-line comment.")
    private List<String> strings = Arrays.asList("root", "local");
    @Comment({
            "This is a multiline comment.",
            "It describes what this field does."
    })
    private Map<String, List<String>> listByStrings = new HashMap<>();
    private Custom custom = new Custom();

    public DatabaseConfig(Path configPath) {
        super(configPath);
    }
    /* optional GETTER and SETTER methods */
}

Example Bukkit plugin

public class ExamplePlugin extends JavaPlugin {
    @Override
    public void onEnable() {
        Path configPath = new File(getDataFolder(), "config.yml").toPath();

        DatabaseConfig config = new DatabaseConfig(configPath);
        try {
            config.loadAndSave();
        } catch (IOException e) {
            /* do something with exception */
        }

        int port = config.getPort();
    }
}