encoding.java

来自「RESIN 3.2 最新源码」· Java 代码 · 共 586 行 · 第 1/2 页

/*
 * Copyright (c) 1998-2008 Caucho Technology -- all rights reserved
 *
 * This file is part of Resin(R) Open Source
 *
 * Each copy or derived work must preserve the copyright notice and this
 * notice unmodified.
 *
 * Resin Open Source 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.
 *
 * Resin Open Source 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, or any warranty
 * of NON-INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Resin Open Source; if not, write to the
 *
 *   Free Software Foundation, Inc.
 *   59 Temple Place, Suite 330
 *   Boston, MA 02111-1307  USA
 *
 * @author Scott Ferguson
 */

package com.caucho.vfs;

import com.caucho.util.CharBuffer;
import com.caucho.vfs.i18n.EncodingReader;
import com.caucho.vfs.i18n.EncodingWriter;
import com.caucho.vfs.i18n.ISO8859_1Writer;
import com.caucho.vfs.i18n.JDKReader;
import com.caucho.vfs.i18n.JDKWriter;

import java.io.InputStream;
import java.io.Reader;
import java.io.UnsupportedEncodingException;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Locale;

/**
 * Converts between the mime encoding names and Java encoding names.
 */
public class Encoding {
  static HashMap<String,String> _javaName;
  static Hashtable<String,String> _mimeName;
  static HashMap<String,String> _localeName;

  // map from an encoding name to its EncodingReader factory.
  static final HashMap<String,EncodingReader> _readEncodingFactories
    = new HashMap<String,EncodingReader>();
  
  // map from an encoding name to its EncodingWriter factory.
  static final HashMap<String,EncodingWriter> _writeEncodingFactories =
    new HashMap<String,EncodingWriter>();

  static final EncodingWriter _latin1Writer = new ISO8859_1Writer();

  /**
   * Can't create an instance of the encoding class.
   */
  private Encoding() {}

  /**
   * Returns the canonical mime name for the given character encoding.
   *
   * @param encoding character encoding name, possibly an alias
   *
   * @return canonical mime name for the encoding.
   */
  public static String getMimeName(String encoding)
  {
    if (encoding == null)
      return null;

    String value = _mimeName.get(encoding);
    if (value != null)
      return value;

    String upper = normalize(encoding);

    String lookup = _mimeName.get(upper);

    value = lookup == null ? upper : lookup;

    _mimeName.put(encoding, value);

    return value;
  }

  /**
   * Returns the canonical mime name for the given locale.
   *
   * @param locale locale to use.
   *
   * @return canonical mime name for the encoding.
   */
  public static String getMimeName(Locale locale)
  {
    if (locale == null)
      return "ISO-8859-1";

    String mimeName = _localeName.get(locale.toString());
    if (mimeName == null)
      mimeName = _localeName.get(locale.getLanguage());

    if (mimeName == null)
      return "ISO-8859-1";
    else
      return mimeName;
  }

  /**
   * Returns a Reader to translate bytes to characters.  If a specialized
   * reader exists in com.caucho.vfs.i18n, use it.
   *
   * @param is the input stream.
   * @param encoding the encoding name.
   *
   * @return a reader for the translation
   */
  public static Reader getReadEncoding(InputStream is, String encoding)
    throws UnsupportedEncodingException
  {
    return getReadFactory(encoding).create(is);
  }

  /**
   * Returns a Reader to translate bytes to characters.  If a specialized
   * reader exists in com.caucho.vfs.i18n, use it.
   *
   * @param is the input stream.
   * @param encoding the encoding name.
   *
   * @return a reader for the translation
   */
  public static EncodingReader getReadFactory(String encoding)
    throws UnsupportedEncodingException
  {
    EncodingReader factory = null;
    
    synchronized (_readEncodingFactories) {
      factory = _readEncodingFactories.get(encoding);

      if (factory == null) {
        try {
          String javaEncoding = Encoding.getJavaName(encoding);

          if (javaEncoding == null)
            javaEncoding = "ISO8859_1";

          String className = "com.caucho.vfs.i18n." + javaEncoding + "Reader";
        
          Class cl = Class.forName(className);

          factory = (EncodingReader) cl.newInstance();
          factory.setJavaEncoding(javaEncoding);
        } catch (Throwable e) {
        }

        if (factory == null) {
          String javaEncoding = Encoding.getJavaName(encoding);

          if (javaEncoding == null)
            javaEncoding = "ISO8859_1";
          
          factory = new JDKReader();
          factory.setJavaEncoding(javaEncoding);
        }

        _readEncodingFactories.put(encoding, factory);
      }
    }

    return factory;
  }

  /**
   * Returns an EncodingWriter to translate characters to bytes.
   *
   * @param encoding the encoding name.
   *
   * @return a writer for the translation
   */
  public static EncodingWriter getWriteEncoding(String encoding)
  {
    EncodingWriter factory = _writeEncodingFactories.get(encoding);

    if (factory != null)
      return factory.create();

    synchronized (_writeEncodingFactories) {
      factory = _writeEncodingFactories.get(encoding);

      if (factory == null) {
        try {
          String javaEncoding = Encoding.getJavaName(encoding);

          if (javaEncoding == null)
            javaEncoding = "ISO8859_1";

          String className = "com.caucho.vfs.i18n." + javaEncoding + "Writer";
        
          Class cl = Class.forName(className);

          factory = (EncodingWriter) cl.newInstance();
	  factory.setJavaEncoding(javaEncoding);
        } catch (Throwable e) {
        }

        if (factory == null) {
          factory = new JDKWriter();
          String javaEncoding = Encoding.getJavaName(encoding);

          if (javaEncoding == null)
            javaEncoding = "ISO8859_1";
          factory.setJavaEncoding(javaEncoding);
        }

        _writeEncodingFactories.put(encoding, factory);
      }
    }

    // return factory.create(factory.getJavaEncoding());
    // charset uses the original encoding, not the java encoding
    return factory.create(encoding);
  }

  /**
   * Returns the latin 1 writer.
   */
  public static EncodingWriter getLatin1Writer()
  {
    return _latin1Writer;
  }

  /**
   * Returns the Java name for the given encoding.
   *
   * @param encoding character encoding name
   *
   * @return Java encoding name
   */
  public static String getJavaName(String encoding)
  {
    if (encoding == null)
      return null;

    String upper = normalize(encoding);

    String javaName = null;
    
    javaName = _javaName.get(upper);
    if (javaName != null)
      return javaName;
    
    String lookup = _mimeName.get(upper);

    if (lookup != null)
      javaName = _javaName.get(lookup);

    return javaName == null ? upper : javaName;
  }

  /**
   * Returns the Java name for the given locale.
   *
   * @param locale the locale to use
   *
   * @return Java encoding name
   */
  public static String getJavaName(Locale locale)
  {
    if (locale == null)
      return null;

    return getJavaName(getMimeName(locale));
  }

  /**
   * Normalize the user's encoding name to avoid case issues.
   */
  private static String normalize(String name)
  {
    CharBuffer cb = CharBuffer.allocate();

    int len = name.length();
    for (int i = 0; i < len; i++) {