1. /*

  2.  * The Apache Software License, Version 1.1

  3.  *

  4.  *

  5.  * Copyright (c) 2000-2002 The Apache Software Foundation.  All rights 

  6.  * reserved.

  7.  *

  8.  * Redistribution and use in source and binary forms, with or without

  9.  * modification, are permitted provided that the following conditions

  10.  * are met:

  11.  *

  12.  * 1. Redistributions of source code must retain the above copyright

  13.  *    notice, this list of conditions and the following disclaimer. 

  14.  *

  15.  * 2. Redistributions in binary form must reproduce the above copyright

  16.  *    notice, this list of conditions and the following disclaimer in

  17.  *    the documentation and/or other materials provided with the

  18.  *    distribution.

  19.  *

  20.  * 3. The end-user documentation included with the redistribution,

  21.  *    if any, must include the following acknowledgment:  

  22.  *       "This product includes software developed by the

  23.  *        Apache Software Foundation (http://www.apache.org/)."

  24.  *    Alternately, this acknowledgment may appear in the software itself,

  25.  *    if and wherever such third-party acknowledgments normally appear.

  26.  *

  27.  * 4. The names "Xerces" and "Apache Software Foundation" must

  28.  *    not be used to endorse or promote products derived from this

  29.  *    software without prior written permission. For written 

  30.  *    permission, please contact apache@apache.org.

  31.  *

  32.  * 5. Products derived from this software may not be called "Apache",

  33.  *    nor may "Apache" appear in their name, without prior written

  34.  *    permission of the Apache Software Foundation.

  35.  *

  36.  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED

  37.  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

  38.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

  39.  * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR

  40.  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

  41.  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

  42.  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF

  43.  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND

  44.  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,

  45.  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT

  46.  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

  47.  * SUCH DAMAGE.

  48.  * ====================================================================

  49.  *

  50.  * This software consists of voluntary contributions made by many

  51.  * individuals on behalf of the Apache Software Foundation and was

  52.  * originally based on software copyright (c) 1999, International

  53.  * Business Machines, Inc., http://www.apache.org.  For more

  54.  * information on the Apache Software Foundation, please see

  55.  * <http://www.apache.org/>.

  56.  */

  57. 

  58. 

  59. package com.sun.org.apache.xml.internal.serialize;

  60. 

  61. import java.io.OutputStream;

  62. import java.io.OutputStreamWriter;

  63. import java.io.UnsupportedEncodingException;

  64. import java.io.Writer;

  65. import com.sun.org.apache.xerces.internal.util.EncodingMap;

  66. import java.nio.charset.Charset;

  67. import java.nio.charset.CharsetEncoder;

  68. import java.nio.charset.UnsupportedCharsetException;

  69. import java.nio.charset.IllegalCharsetNameException;

  70. /**

  71.  * This class represents an encoding.

  72.  *

  73.  * @version $Id: EncodingInfo.java,v 1.2 2003/12/05 10:08:55 vk112360 Exp $

  74.  */

  75. public class EncodingInfo {

  76. 

  77.     // Method: sun.io.CharToByteConverter.getConverter(java.lang.String)

  78.     private static java.lang.reflect.Method fgGetConverterMethod = null; 

  79.     

  80.     // Method: sun.io.CharToByteConverter.canConvert(char)

  81.     private static java.lang.reflect.Method fgCanConvertMethod = null;

  82.     

  83.     // Flag indicating whether or not sun.io.CharToByteConverter is available.

  84.     private static boolean fgConvertersAvailable = false;

  85.     

  86.     // An array to hold the argument for a method of CharToByteConverter.

  87.     private Object [] fArgsForMethod = null;

  88.     

  89.     // name of encoding as registered with IANA;

  90.     // preferably a MIME name, but aliases are fine too.

  91.     String ianaName;

  92.     String javaName;

  93.     int lastPrintable;

  94.     

  95.     // The charToByteConverter with which we test unusual characters.

  96.     Object fCharToByteConverter = null;

  97.     

  98.     // Is the converter null because it can't be instantiated

  99.     // for some reason (perhaps we're running with insufficient authority as 

  100.     // an applet?

  101.     boolean fHaveTriedCToB = false;

  102. 	Charset nioCharset = null;

  103. 	CharsetEncoder nioCharEncoder = null;

  104.     /**

  105.      * Creates new <code>EncodingInfo</code> instance.

  106.      */

  107.     public EncodingInfo(String ianaName, String javaName, int lastPrintable) {

  108.         this.ianaName = ianaName;

  109.         this.javaName = EncodingMap.getIANA2JavaMapping(ianaName);

  110.         this.lastPrintable = lastPrintable;

  111. 		try{

  112. 			 nioCharset = Charset.forName(this.javaName);

  113. 			 if(nioCharset.canEncode())

  114. 			 	nioCharEncoder = nioCharset.newEncoder();

  115. 		}catch(IllegalCharsetNameException ie){

  116. 			nioCharset = null;

  117. 			nioCharEncoder = null;

  118. 		}catch(UnsupportedCharsetException ue){

  119. 			nioCharset = null;

  120. 			nioCharEncoder = null;

  121. 		}

  122.     }

  123. 

  124.     /**

  125.      * Returns a MIME charset name of this encoding.

  126.      */

  127.     public String getIANAName() {

  128.         return this.ianaName;

  129.     }

  130. 

  131.     /**

  132.      * Returns a writer for this encoding based on

  133.      * an output stream.

  134.      *

  135.      * @return A suitable writer

  136.      * @exception UnsupportedEncodingException There is no convertor

  137.      *  to support this encoding

  138.      */

  139.     public Writer getWriter(OutputStream output)

  140.         throws UnsupportedEncodingException {

  141.         // this should always be true!

  142.         if (javaName != null) 

  143.             return new OutputStreamWriter(output, javaName);

  144.         javaName = EncodingMap.getIANA2JavaMapping(ianaName);

  145.         if(javaName == null) 

  146.             // use UTF-8 as preferred encoding

  147.             return new OutputStreamWriter(output, "UTF8");

  148.         return new OutputStreamWriter(output, javaName);

  149.     }

  150.     /**

  151.      * Checks whether the specified character is printable or not

  152.      * in this encoding.

  153.      *

  154.      * @param ch a code point (0-0x10ffff)

  155.      */

  156.     public boolean isPrintable(char ch) {

  157.         if(ch <= this.lastPrintable) 

  158.             return true;

  159. 		if(nioCharEncoder != null)

  160. 			return nioCharEncoder.canEncode(ch);

  161. 

  162. 		//We should not reach here , if we reach due to 

  163. 		//charset not supporting encoding then fgConvertersAvailable 

  164. 		//should take care of returning false.

  165. 

  166.         if(fCharToByteConverter == null) {

  167.             if(fHaveTriedCToB || !fgConvertersAvailable) {

  168.                 // forget it; nothing we can do...

  169.                 return false;

  170.             }

  171.             if (fArgsForMethod == null) {

  172.                 fArgsForMethod = new Object [1];

  173.             }

  174.             // try and create it:

  175.             try {

  176.                 fArgsForMethod[0] = javaName;

  177.                 fCharToByteConverter = fgGetConverterMethod.invoke(null, fArgsForMethod);

  178.             } catch(Exception e) {   

  179.                 // don't try it again...

  180.                 fHaveTriedCToB = true;

  181.                 return false;

  182.             }

  183.         }

  184.         try {

  185.             fArgsForMethod[0] = new Character(ch);

  186.             return ((Boolean) fgCanConvertMethod.invoke(fCharToByteConverter, fArgsForMethod)).booleanValue();

  187.         } catch (Exception e) {

  188.             // obviously can't use this converter; probably some kind of

  189.             // security restriction

  190.             fCharToByteConverter = null;

  191.             fHaveTriedCToB = false;

  192.             return false;

  193.         }

  194.     }

  195. 

  196.     // is this an encoding name recognized by this JDK?

  197.     // if not, will throw UnsupportedEncodingException

  198.     public static void testJavaEncodingName(String name)  throws UnsupportedEncodingException {

  199.         final byte [] bTest = {(byte)'v', (byte)'a', (byte)'l', (byte)'i', (byte)'d'};

  200.         String s = new String(bTest, name);

  201.     }

  202.     

  203.     // Attempt to get methods for char to byte 

  204.     // converter on class initialization.

  205.     static {

  206.         try {

  207.             Class clazz = Class.forName("sun.io.CharToByteConverter");

  208.             fgGetConverterMethod = clazz.getMethod("getConverter", new Class [] {String.class});

  209.             fgCanConvertMethod = clazz.getMethod("canConvert", new Class [] {Character.TYPE});

  210.             fgConvertersAvailable = true;

  211.         }

  212.         // ClassNotFoundException, NoSuchMethodException or SecurityException

  213.         // Whatever the case, we cannot use sun.io.CharToByteConverter.

  214.         catch (Exception exc) {

  215.             fgGetConverterMethod = null;

  216.             fgCanConvertMethod = null;

  217.             fgConvertersAvailable = false;

  218.         }

  219.     }

  220. }