ConfigLib/README.md

# 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. `@Comment`s 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
```java
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
```java
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
```java
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();
    }
}
```