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Powerful, easy-to-use and multi-language configuration library for the JVM - core module

There is a newer version: 3.8.1

package com.electronwill.nightconfig.core;

import com.electronwill.nightconfig.core.utils.ConfigWrapper;
import com.electronwill.nightconfig.core.utils.TransformingMap;
import com.electronwill.nightconfig.core.utils.TransformingSet;

import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * A checker wrapped around a configuration. It checks that all the values put into the config are
 * supported supported by the config's format (as per the {@link ConfigFormat#supportsType(Class)}
 * method. Trying to insert an unsupported value throws an IllegalArgumentException.
 *
 * @author TheElectronWill
 */
class CheckedConfig extends ConfigWrapper {
	/**
	 * Creates a new CheckedConfig around a given configuration.
	 * 
	 * The values that are in the config when this method is called are also checked.
	 *
	 * @param config the configuration to wrap
	 */
	CheckedConfig(Config config) {
		super(config);
		config.valueMap().forEach((k, v) -> checkValue(v));
		//The config might already contain some elements and we must be sure that they are all supported
	}

	@Override
	public Config checked() {
		return this;
	}

	@Override
	public  T set(List path, Object value) {
		return super.set(path, checkedValue(value));
	}

	@Override
	public boolean add(List path, Object value) {
		return super.add(path, checkedValue(value));
	}

	@Override
	public Map valueMap() {
		return new TransformingMap<>(super.valueMap(), v -> v, this::checkedValue, o -> o);
	}

	@Override
	public Set entrySet() {
		return new TransformingSet<>((Set)super.entrySet(), v -> v, this::checkedValue, o -> o);
	}

	@Override
	public String toString() {
		return "checked of " + config;
	}

	/**
	 * Checks that a value is supported by the config. Throws an unchecked exception if the value
	 * isn't supported.
	 */
	private void checkValue(Object value) {
		ConfigFormat format = configFormat();
		if (value != null && !format.supportsType(value.getClass())) {
			throw new IllegalArgumentException(
					"Unsupported value type: " + value.getClass().getTypeName());
		} else if (value == null && !format.supportsType(null)) {
			throw new IllegalArgumentException(
					"Null values aren't supported by this configuration.");
		}
		if (value instanceof Config) {
			((Config)value).valueMap().forEach((k, v) -> checkValue(v));
		}
	}

	/**
	 * Checks that a value is supported by the config, and returns it if it's supported. Throws an
	 * unchecked exception if the value isn't supported.
	 */
	private  T checkedValue(T value) {
		checkValue(value);
		return value;
	}
}