/*
* Copyright (c) 2002-2012 Alibaba Group Holding Limited.
* All rights reserved.
*
* 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.alibaba.citrus.util.i18n;
import static com.alibaba.citrus.util.Assert.*;
import static com.alibaba.citrus.util.StringUtil.*;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CharsetEncoder;
import java.nio.charset.UnsupportedCharsetException;
import java.util.Locale;
import com.alibaba.citrus.util.StringUtil;
/**
* 代表一个locale信息。
* <p>
* 即使charset不合法，本类也不会报错。请使用<code>LocaleUtil.isCharsetSupported()</code>
* 方法来判断charset的合法性。
* </p>
*
* @author Michael Zhou
*/
public final class LocaleInfo implements Cloneable, Externalizable {
private static final long serialVersionUID = 3257847675461251635L;
private Locale locale;
private Charset charset;
/**
* 解析并创建locale信息。
*
* @param name locale信息的字符串，包含locale和charset信息，以“:”分隔
* @return locale信息
*/
public static LocaleInfo parse(String name) {
name = assertNotNull(trimToNull(name), "no locale name");
int index = name.indexOf(":");
String localePart = name;
String charsetPart = null;
if (index >= 0) {
localePart = name.substring(0, index);
charsetPart = name.substring(index + 1);
}
Locale locale = LocaleUtil.parseLocale(localePart);
String charset = StringUtil.trimToNull(charsetPart);
return new LocaleInfo(locale, charset);
}
/** 创建系统默认的locale信息。 */
public LocaleInfo() {
this.locale = assertNotNull(Locale.getDefault(), "system locale");
this.charset = assertNotNull(Charset.defaultCharset(), "system charset");
}
/**
* 创建locale信息。
*
* @param locale 区域信息
*/
public LocaleInfo(Locale locale) {
this(locale, null, LocaleUtil.getDefault());
}
/**
* 创建locale信息。
*
* @param locale 区域信息
* @param charset 编码字符集
*/
public LocaleInfo(Locale locale, String charset) {
this(locale, charset, LocaleUtil.getDefault());
}
/**
* 创建locale信息。
*
* @param locale 区域信息
* @param charset 编码字符集
* @param fallbackLocaleInfo 上一级locale信息，如果未提供locale和charset，则从上一级中取得。
*/
LocaleInfo(Locale locale, String charset, LocaleInfo fallbackLocaleInfo) {
assertNotNull(fallbackLocaleInfo, "fallbackLocaleInfo");
charset = trimToNull(charset);
if (locale == null) {
locale = fallbackLocaleInfo.getLocale();
if (charset == null) {
charset = fallbackLocaleInfo.getCharset().name();
}
} else {
if (charset == null) {
charset = "UTF-8"; // 如果指定了locale，但未指定charset，则使用万能的UTF-8
}
}
this.locale = locale;
try {
this.charset = Charset.forName(charset);
} catch (UnsupportedCharsetException e) {
this.charset = new UnknownCharset(charset);
}
}
/**
* 取得区域。
*
* @return 区域
*/
public Locale getLocale() {
return locale;
}
/**
* 取得编码字符集。
*
* @return 编码字符集
*/
public Charset getCharset() {
return charset;
}
/** 判断charset是否被支持。 */
public boolean isCharsetSupported() {
return !(charset instanceof UnknownCharset);
}
/** 判断charset是否被支持。 */
public LocaleInfo assertCharsetSupported() throws UnsupportedCharsetException {
if (charset instanceof UnknownCharset) {
throw new UnsupportedCharsetException(charset.name());
}
return this;
}
/**
* 比较对象。
*
* @param o 被比较的对象
* @return 如果对象等效，则返回<code>true</code>
*/
@Override
public boolean equals(Object o) {
if (o == null) {
return false;
}
if (o == this) {
return true;
}
if (!(o instanceof LocaleInfo)) {
return false;
}
LocaleInfo otherLocaleInfo = (LocaleInfo) o;
return locale.equals(otherLocaleInfo.locale) && charset.equals(otherLocaleInfo.charset);
}
@Override
public int hashCode() {
return charset.hashCode() * 31 + locale.hashCode();
}
@Override
public Object clone() {
try {
return super.clone();
} catch (CloneNotSupportedException e) {
unexpectedException(e);
return null;
}
}
public void writeExternal(ObjectOutput out) throws IOException {
out.writeUTF(toString());
}
public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
LocaleInfo info = parse(in.readUTF());
locale = info.getLocale();
charset = info.getCharset();
}
@Override
public String toString() {
return locale + ":" + charset;
}
/** 代表一个不能识别的charset。 */
static class UnknownCharset extends Charset {
public UnknownCharset(String name) {
super(assertNotNull(name, "charset name"), null);
}
@Override
public boolean contains(Charset cs) {
return false;
}
@Override
public CharsetDecoder newDecoder() {
unsupportedOperation("Could not create decoder for unknown charset: " + name());
return null;
}
@Override
public CharsetEncoder newEncoder() {
unsupportedOperation("Could not create encoder for unknown charset: " + name());
return null;
}
}
}