BaseSettings.java

package com.frozenfractal;

import com.badlogic.gdx.Preferences;
import com.badlogic.gdx.utils.Json;

import java.util.Locale;

public class BaseSettings {

	protected final Preferences prefs;

	protected BaseSettings(Preferences prefs) {
		this.prefs = prefs;
	}

	protected BooleanSetting booleanSetting(String key, boolean defaultValue) {
		return new BooleanSetting(key, defaultValue);
	}

	protected IntSetting intSetting(String key, int defaultValue) {
		return new IntSetting(key, defaultValue);
	}

	protected StringSetting stringSetting(String key, String defaultValue) {
		return new StringSetting(key, defaultValue);
	}

	protected <T extends Enum<T>> EnumSetting<T> enumSetting(Class<T> clazz, String key, T defaultValue) {
		return new EnumSetting<T>(clazz, key, defaultValue);
	}

	protected LocaleSetting localeSetting(String keyPrefix, Locale defaultValue) {
		return new LocaleSetting(keyPrefix, defaultValue);
	}

	protected <T> JsonSetting<T> jsonSetting(Class<T> clazz, Json json, String key, T defaultValue) {
		return new JsonSetting<T>(clazz, json, key, defaultValue);
	}

	protected abstract class Setting<T> {

		protected final String key;
		protected final T defaultValue;
		private T cachedValue;

		protected Setting(String key, T defaultValue) {
			this.key = key;
			this.defaultValue = defaultValue;
		}

		protected abstract T getPref();
		protected abstract void setPref(T value);

		public T get() {
			if (cachedValue == null) {
				cachedValue = getPref();
			}
			return cachedValue;
		}

		public void set(T value) {
			this.cachedValue = value;
			setPref(value);
			prefs.flush();
		}
	}

	public class BooleanSetting extends Setting<Boolean> {

		private BooleanSetting(String key, boolean defaultValue) {
			super(key, defaultValue);
		}

		@Override
		protected Boolean getPref() {
			return prefs.getBoolean(key, defaultValue);
		}

		@Override
		protected void setPref(Boolean value) {
			prefs.putBoolean(key, value);
		}
	}

	public class IntSetting extends Setting<Integer> {

		private IntSetting(String key, int defaultValue) {
			super(key, defaultValue);
		}

		@Override
		protected Integer getPref() {
			return prefs.getInteger(key, defaultValue);
		}

		@Override
		protected void setPref(Integer value) {
			prefs.putInteger(key, value);
		}
	}

	public class StringSetting extends Setting<String> {

		private StringSetting(String key, String defaultValue) {
			super(key, defaultValue);
		}

		@Override
		protected String getPref() {
			return prefs.getString(key, defaultValue);
		}

		@Override
		protected void setPref(String value) {
			prefs.putString(key, value);
		}
	}

	public class EnumSetting<T extends Enum<T>> extends Setting<T> {

		private final Class<T> clazz;

		private EnumSetting(Class<T> clazz, String key, T defaultValue) {
			super(key, defaultValue);
			this.clazz = clazz;
		}

		@Override
		protected T getPref() {
			String s = prefs.getString(key, null);
			if (s == null) {
				return defaultValue;
			}
			try {
				return Enum.valueOf(clazz, s);
			} catch (IllegalArgumentException ex) {
				return defaultValue;
			}
		}

		@Override
		protected void setPref(T value) {
			prefs.putString(key, value.name());
		}
	}

	public class LocaleSetting extends Setting<Locale> {

		protected LocaleSetting(String key, Locale defaultValue) {
			super(key, defaultValue);
		}

		@Override
		protected Locale getPref() {
			return new Locale(
				prefs.getString(key + "Language", defaultValue.getLanguage()),
				prefs.getString(key + "Country", defaultValue.getCountry()),
				prefs.getString(key + "Variant", defaultValue.getVariant()));
		}

		@Override
		protected void setPref(Locale value) {
			prefs.putString(key + "Language", value.getLanguage());
			prefs.putString(key + "Country", value.getCountry());
			prefs.putString(key + "Variant", value.getVariant());
		}
	}

	public class JsonSetting<T> extends Setting<T> {

		private final Class<T> clazz;
		private final Json json;

		protected JsonSetting(Class<T> clazz, Json json, String key, T defaultValue) {
			super(key, defaultValue);
			this.clazz = clazz;
			this.json = json;
		}

		@Override
		protected T getPref() {
			String s = prefs.getString(key, null);
			if (s == null) {
				return defaultValue;
			}
			try {
				return json.fromJson(clazz, s);
			} catch (Exception ex) {
				return defaultValue;
			}
		}

		@Override
		protected void setPref(T value) {
			if (value != null) {
				prefs.putString(key, json.toJson(value));
			} else {
				prefs.remove(key);
			}
		}
	}
}