/*
* Copyright 2009 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.gwt.i18n.server;
import com.google.gwt.i18n.shared.GwtLocale;
import com.google.gwt.i18n.shared.GwtLocaleFactory;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
/**
* Creates server-side GwtLocale instances. Thread-safe.
*/
public class GwtLocaleFactoryImpl implements GwtLocaleFactory {
private static boolean isAlpha(String str, int min, int max) {
return matches(str, min, max, true);
}
private static boolean isDigit(String str, int min, int max) {
return matches(str, min, max, false);
}
/**
* Check if the supplied string matches length and composition requirements.
*
* @param str string to check
* @param min minimum length
* @param max maximum length
* @param lettersNotDigits true if all characters should be letters, false if
* all characters should be digits
* @return true if the string is of a proper length and contains only the
* specified characters
*/
private static boolean matches(String str, int min, int max,
boolean lettersNotDigits) {
int len = str.length();
if (len < min || len > max) {
return false;
}
for (int i = 0; i < len; ++i) {
if ((lettersNotDigits && !Character.isLetter(str.charAt(i)))
|| (!lettersNotDigits && !Character.isDigit(str.charAt(i)))) {
return false;
}
}
return true;
}
private static String titleCase(String str) {
if (str.length() < 2) {
return str.toUpperCase(Locale.ENGLISH);
}
return String.valueOf(Character.toTitleCase(str.charAt(0))) +
str.substring(1).toLowerCase(Locale.ENGLISH);
}
private final Object instanceCacheLock = new Object[0];
// Locales are stored pointing at themselves. A new instance is created,
// which is pretty cheap, then looked up here. If it exists, the old
// one is used instead to preserved cached data structures.
private Map<GwtLocaleImpl, GwtLocaleImpl> instanceCache
= new HashMap<GwtLocaleImpl, GwtLocaleImpl>();
/**
* Clear an embedded cache of instances when they are no longer needed.
* <p>
* Note that GwtLocale instances constructed after this is called will not
* maintain identity with instances constructed before this call.
*/
public void clear() {
synchronized (instanceCacheLock) {
instanceCache.clear();
}
}
public GwtLocale fromComponents(String language, String script,
String region, String variant) {
if (language != null && language.length() == 0) {
language = null;
}
if (language != null) {
language = language.toLowerCase(Locale.ENGLISH);
}
if (script != null && script.length() == 0) {
script = null;
}
if (script != null) {
script = titleCase(script);
}
if (region != null && region.length() == 0) {
region = null;
}
if (region != null) {
region = region.toUpperCase(Locale.ENGLISH);
}
if (variant != null && variant.length() == 0) {
variant = null;
}
if (variant != null) {
variant = variant.toUpperCase(Locale.ENGLISH);
}
GwtLocaleImpl locale = new GwtLocaleImpl(this, language, region, script,
variant);
synchronized (instanceCacheLock) {
if (instanceCache.containsKey(locale)) {
return instanceCache.get(locale);
}
instanceCache.put(locale, locale);
}
return locale;
}
/**
* @throws IllegalArgumentException if the supplied locale does not match
* BCP47 structural requirements.
*/
public GwtLocale fromString(String localeName) {
String language = null;
String script = null;
String region = null;
String variant = null;
if (localeName != null && !GwtLocale.DEFAULT_LOCALE.equals(localeName)) {
// split into component parts
ArrayList<String> localeParts = new ArrayList<String>();
String[] parts = localeName.split("[-_]");
for (int i = 0; i < parts.length; ++i) {
if (parts[i].length() == 1 && i + 1 < parts.length) {
localeParts.add(parts[i] + '-' + parts[++i]);
} else {
localeParts.add(parts[i]);
}
}
// figure out the role of each part
int partIdx = 1;
int numParts = localeParts.size();
if (numParts > 0) {
// Treat an initial private-use tag as the language tag
// Otherwise, language tags are 2-3 characters plus up to three
// 3-letter extensions, or 4-8 characters.
language = localeParts.get(0);
int len = language.length();
// TODO: verify language tag length
// See if we have extended language tags
if ((len == 2 || len == 3) && partIdx < numParts) {
String part = localeParts.get(partIdx);
while (partIdx < numParts && partIdx < 4
&& isAlpha(part, 3, 3)) {
language += '-' + part;
if (++partIdx >= numParts) {
break;
}
part = localeParts.get(partIdx);
}
}
}
if (numParts > partIdx
&& isAlpha(localeParts.get(partIdx), 4, 4)) {
// Scripts are exactly 4 letters
script = localeParts.get(partIdx++);
}
if (partIdx < numParts) {
// Regions may be 2 letters or 3 digits
String part = localeParts.get(partIdx);
if (isAlpha(part, 2, 2) || isDigit(part, 3, 3)) {
region = part;
++partIdx;
}
}
if (partIdx < numParts) {
// Variants are 5-8 alphanum, or 4 alphanum if first is digit
String part = localeParts.get(partIdx);
int len = part.length();
if ((len >= 5 && len <= 8) || (len == 4
&& Character.isDigit(part.charAt(0)))) {
variant = part;
++partIdx;
}
}
if (partIdx < numParts) {
throw new IllegalArgumentException("Unrecognized locale format: "
+ localeName);
}
}
return fromComponents(language, script, region, variant);
}
public GwtLocale getDefault() {
return fromComponents(null, null, null, null);
}
}