I18n.java

/*******************************************************************************
 * Breakout Cave Survey Visualizer
 *
 * Copyright (C) 2014 James Edwards
 *
 * jedwards8 at fastmail dot fm
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *******************************************************************************/
package org.andork.i18n;

import java.text.DateFormat;
import java.text.MessageFormat;
import java.util.Arrays;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.MissingResourceException;
import java.util.ResourceBundle;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;

import org.andork.bind2.BiFunctionBinder;
import org.andork.bind2.Binder;
import org.andork.bind2.BinderHolder;
import org.andork.bind2.DefaultBinder;
import org.andork.bind2.FunctionBinder;
import org.andork.bind2.ListBinder;
import org.andork.bind2.OpaqueBinderHolder;

public class I18n {
	public static class Localizer {
		public final String name;

		private Binder<ResourceBundle> bundleBinder;

		private final Set<String> missingKeys = new HashSet<String>();

		private Localizer(String name, Binder<Locale> localeBinder) {
			super();
			this.name = name;
			bundleBinder = new FunctionBinder<>(localeBinder, locale -> {
				if (disableBundleLoading || locale == null) {
					return null;
				}

				try {
					return ResourceBundle.getBundle(name, locale);
				} catch (MissingResourceException ex) {
					ex.printStackTrace();
				}
				return null;
			}).convertToWeakReferencing();
		}

		public Binder<String> formattedStringBinder(Binder<String> keyBinder, Binder<?>... argBinders) {
			return new BiFunctionBinder<String, List<Object>, String>(
					stringBinder(keyBinder),
					new ListBinder<Object>(Arrays.asList(argBinders)),
					(pattern, args) -> pattern == null || args == null ? null : MessageFormat.format(pattern,
							args.toArray()))
									.convertToWeakReferencing();
		}

		public Binder<String> formattedStringBinder(String key, Object... args) {
			return new FunctionBinder<ResourceBundle, String>(
					bundleBinder,
					bundle -> MessageFormat.format(getString(bundle, key), args))
							.convertToWeakReferencing();
		}

		public ResourceBundle getBundle() {
			return bundleBinder.get();
		}

		public String getFormattedString(String key, Object... args) {
			return MessageFormat.format(getString(key), args);
		}

		private String getString(ResourceBundle bundle, String key) {
			try {
				return bundle == null || key == null ? key : bundle.getString(key);
			} catch (MissingResourceException ex) {
				if (missingKeys.add(key)) {
					logger.log(Level.SEVERE, "Missing I18n key: \"" + key + '"', ex);
				}
				return key;
			}
		}

		public String getString(String key) {
			return getString(bundleBinder.get(), key);
		}

		public Binder<String> stringBinder(Binder<String> keyBinder) {
			return new BiFunctionBinder<ResourceBundle, String, String>(
					bundleBinder,
					keyBinder,
					(bundle, key) -> getString(bundle, key))
							.convertToWeakReferencing();
		}

		public Binder<String> stringBinder(String key) {
			return new FunctionBinder<ResourceBundle, String>(
					bundleBinder,
					bundle -> getString(bundle, key))
							.convertToWeakReferencing();
		}
	}

	private static final Logger logger = Logger.getLogger(I18n.class.getName());

	private static BinderHolder<Locale> localeBinderHolder = new BinderHolder<>();

	private static OpaqueBinderHolder<Locale> opaqueLocaleBinderHolder = new OpaqueBinderHolder<>(localeBinderHolder);

	private static final Map<String, Localizer> localizers = new HashMap<String, Localizer>();

	private static boolean disableBundleLoading = System.getProperties().containsKey(
			"disableBundleLoading");

	static {
		setLocale(Locale.getDefault());
	}

	public static Localizer forClass(Class<?> cls) {
		return forName(cls.getName());
	}

	public static Binder<String> formattedDateTimeBinder(Binder<Date> dateBinder, int dateStyle, int timeStyle) {
		Binder<DateFormat> formatBinder = new FunctionBinder<>(localeBinderHolder,
				locale -> locale == null ? DateFormat.getDateTimeInstance(dateStyle, timeStyle)
						: DateFormat.getDateTimeInstance(dateStyle, timeStyle, locale));

		return new BiFunctionBinder<>(dateBinder, formatBinder,
				(date, format) -> date == null || format == null ? null : format.format(date));
	}

	public static Localizer forName(String name) {
		Localizer result = localizers.get(name);
		if (result == null) {
			result = new Localizer(name, localeBinderHolder);
			localizers.put(name, result);
		}
		return result;
	}

	public static Locale getLocale() {
		return localeBinderHolder.get();
	}

	public static Binder<Locale> getLocaleBinder() {
		return opaqueLocaleBinderHolder;
	}

	public static boolean isDisableBundleLoading() {
		return disableBundleLoading;
	}

	public static void setDisableBundleLoading(boolean disableBundleLoading) {
		I18n.disableBundleLoading = disableBundleLoading;
	}

	public static void setLocale(Locale locale) {
		localeBinderHolder.binderLink.bind(new DefaultBinder<>(locale));
	}

	public static void setLocaleBinder(Binder<? extends Locale> binder) {
		localeBinderHolder.binderLink.bind(binder);
	}
}