Coverage Report

Coverage Report - org.codehaus.plexus.util.xml.XmlReader

Classes in this File
Line Coverage
Branch Coverage
Complexity
XmlReader
46%
101/221
23%
43/184
3.308
 /*
  * Copyright 2004 Sun Microsystems, 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 org.codehaus.plexus.util.xml;
 
 import java.io.BufferedInputStream;
 import java.io.BufferedReader;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.Reader;
 import java.io.StringReader;
 import java.net.URL;
 import java.net.URLConnection;
 import java.net.HttpURLConnection;
 import java.util.regex.Pattern;
 import java.util.regex.Matcher;
 import java.text.MessageFormat;
 
 /**
  * Character stream that handles (or at least attemtps to) all the necessary Voodo to figure out the charset encoding of
  * the XML document within the stream.
  * <p>
  * IMPORTANT: This class is not related in any way to the org.xml.sax.XMLReader. This one IS a character stream.
  * <p>
  * All this has to be done without consuming characters from the stream, if not the XML parser will not recognized the
  * document as a valid XML. This is not 100% true, but it's close enough (UTF-8 BOM is not handled by all parsers right
  * now, XmlReader handles it and things work in all parsers).
  * <p>
  * The XmlReader class handles the charset encoding of XML documents in Files, raw streams and HTTP streams by offering
  * a wide set of constructors.
  * <P>
  * By default the charset encoding detection is lenient, the constructor with the lenient flag can be used for an script
  * (following HTTP MIME and XML specifications). All this is nicely explained by Mark Pilgrim in his blog, <a
  * href="http://diveintomark.org/archives/2004/02/13/xml-media-types"> Determining the character encoding of a feed</a>.
  * <p>
  * 
  * @author Alejandro Abdelnur
  * @version revision 1.17 taken on 26/06/2007 from Rome (see https://rome.dev.java.net/source/browse/rome/src/java/com/sun/syndication/io/XmlReader.java)
  * @deprecated use XmlStreamReader
  * @since 1.4.3
  * @deprecated TO BE REMOVED from here when plexus-utils is upgraded to 1.4.5+ (and prerequisite upgraded to Maven 2.0.6)
  */
 public class XmlReader extends Reader
 {
     private static final int BUFFER_SIZE = 4096;
 
     private static final String UTF_8 = "UTF-8";
 
     private static final String US_ASCII = "US-ASCII";
 
     private static final String UTF_16BE = "UTF-16BE";
 
     private static final String UTF_16LE = "UTF-16LE";
 
     private static final String UTF_16 = "UTF-16";
 
     private static final String EBCDIC = "CP1047";
 
     private static String _staticDefaultEncoding = null;
 
     private Reader _reader;
 
     private String _encoding;
 
     private String _defaultEncoding;
 
     /**
      * Sets the default encoding to use if none is set in HTTP content-type, XML prolog and the rules based on
      * content-type are not adequate. <p/> If it is set to NULL the content-type based rules are used. <p/> By default
      * it is NULL. <p/>
      * 
      * @param encoding
      *            charset encoding to default to.
      */
     public static void setDefaultEncoding( String encoding )
     {
         _staticDefaultEncoding = encoding;
     }
 
     /**
      * Returns the default encoding to use if none is set in HTTP content-type, XML prolog and the rules based on
      * content-type are not adequate. <p/> If it is NULL the content-type based rules are used. <p/>
      * 
      * @return the default encoding to use.
      */
     public static String getDefaultEncoding()
     {
         return _staticDefaultEncoding;
     }
 
     /**
      * Creates a Reader for a File.
      * <p>
      * It looks for the UTF-8 BOM first, if none sniffs the XML prolog charset, if this is also missing defaults to
      * UTF-8.
      * <p>
      * It does a lenient charset encoding detection, check the constructor with the lenient parameter for details.
      * <p>
      * 
      * @param file
      *            File to create a Reader from.
      * @throws IOException
      *             thrown if there is a problem reading the file.
      * 
      */
     public XmlReader( File file ) throws IOException
     {
         this( new FileInputStream( file ) );
     }
 
     /**
      * Creates a Reader for a raw InputStream.
      * <p>
      * It follows the same logic used for files.
      * <p>
      * It does a lenient charset encoding detection, check the constructor with the lenient parameter for details.
      * <p>
      * 
      * @param is
      *            InputStream to create a Reader from.
      * @throws IOException
      *             thrown if there is a problem reading the stream.
      * 
      */
     public XmlReader( InputStream is ) throws IOException
     {
         this( is, true );
     }
 
     /**
      * Creates a Reader for a raw InputStream.
      * <p>
      * It follows the same logic used for files.
      * <p>
      * If lenient detection is indicated and the detection above fails as per specifications it then attempts the
      * following:
      * <p>
      * If the content type was 'text/html' it replaces it with 'text/xml' and tries the detection again.
      * <p>
      * Else if the XML prolog had a charset encoding that encoding is used.
      * <p>
      * Else if the content type had a charset encoding that encoding is used.
      * <p>
      * Else 'UTF-8' is used.
      * <p>
      * If lenient detection is indicated an XmlStreamReaderException is never thrown.
      * <p>
      * 
      * @param is
      *            InputStream to create a Reader from.
      * @param lenient
      *            indicates if the charset encoding detection should be relaxed.
      * @throws IOException
      *             thrown if there is a problem reading the stream.
      * @throws XmlStreamReaderException
      *             thrown if the charset encoding could not be determined according to the specs.
      * 
      */
     public XmlReader( InputStream is, boolean lenient ) throws IOException, XmlStreamReaderException
     {
         _defaultEncoding = _staticDefaultEncoding;
         try
         {
             doRawStream( is, lenient );
         }
         catch ( XmlStreamReaderException ex )
         {
             if ( !lenient )
             {
                 throw ex;
             }
             else
             {
                 doLenientDetection( null, ex );
             }
         }
     }
 
     /**
      * Creates a Reader using the InputStream of a URL.
      * <p>
      * If the URL is not of type HTTP and there is not 'content-type' header in the fetched data it uses the same logic
      * used for Files.
      * <p>
      * If the URL is a HTTP Url or there is a 'content-type' header in the fetched data it uses the same logic used for
      * an InputStream with content-type.
      * <p>
      * It does a lenient charset encoding detection, check the constructor with the lenient parameter for details.
      * <p>
      * 
      * @param url
      *            URL to create a Reader from.
      * @throws IOException
      *             thrown if there is a problem reading the stream of the URL.
      * 
      */
     public XmlReader( URL url ) throws IOException
     {
         this( url.openConnection() );
     }
 
     /**
      * Creates a Reader using the InputStream of a URLConnection.
      * <p>
      * If the URLConnection is not of type HttpURLConnection and there is not 'content-type' header in the fetched data
      * it uses the same logic used for files.
      * <p>
      * If the URLConnection is a HTTP Url or there is a 'content-type' header in the fetched data it uses the same logic
      * used for an InputStream with content-type.
      * <p>
      * It does a lenient charset encoding detection, check the constructor with the lenient parameter for details.
      * <p>
      * 
      * @param conn
      *            URLConnection to create a Reader from.
      * @throws IOException
      *             thrown if there is a problem reading the stream of the URLConnection.
      * 
      */
     public XmlReader( URLConnection conn ) throws IOException
     {
         _defaultEncoding = _staticDefaultEncoding;
         boolean lenient = true;
         if ( conn instanceof HttpURLConnection )
         {
             try
             {
                 doHttpStream( conn.getInputStream(), conn.getContentType(), lenient );
             }
             catch ( XmlStreamReaderException ex )
             {
                 doLenientDetection( conn.getContentType(), ex );
             }
         }
         else if ( conn.getContentType() != null )
         {
             try
             {
                 doHttpStream( conn.getInputStream(), conn.getContentType(), lenient );
             }
             catch ( XmlStreamReaderException ex )
             {
                 doLenientDetection( conn.getContentType(), ex );
             }
         }
         else
         {
             try
             {
                 doRawStream( conn.getInputStream(), lenient );
             }
             catch ( XmlStreamReaderException ex )
             {
                 doLenientDetection( null, ex );
             }
         }
     }
 
     /**
      * Creates a Reader using an InputStream an the associated content-type header.
      * <p>
      * First it checks if the stream has BOM. If there is not BOM checks the content-type encoding. If there is not
      * content-type encoding checks the XML prolog encoding. If there is not XML prolog encoding uses the default
      * encoding mandated by the content-type MIME type.
      * <p>
      * It does a lenient charset encoding detection, check the constructor with the lenient parameter for details.
      * <p>
      * 
      * @param is
      *            InputStream to create the reader from.
      * @param httpContentType
      *            content-type header to use for the resolution of the charset encoding.
      * @throws IOException
      *             thrown if there is a problem reading the file.
      * 
      */
     public XmlReader( InputStream is, String httpContentType ) throws IOException
     {
         this( is, httpContentType, true );
     }
 
     /**
      * Creates a Reader using an InputStream an the associated content-type header. This constructor is lenient
      * regarding the encoding detection.
      * <p>
      * First it checks if the stream has BOM. If there is not BOM checks the content-type encoding. If there is not
      * content-type encoding checks the XML prolog encoding. If there is not XML prolog encoding uses the default
      * encoding mandated by the content-type MIME type.
      * <p>
      * If lenient detection is indicated and the detection above fails as per specifications it then attempts the
      * following:
      * <p>
      * If the content type was 'text/html' it replaces it with 'text/xml' and tries the detection again.
      * <p>
      * Else if the XML prolog had a charset encoding that encoding is used.
      * <p>
      * Else if the content type had a charset encoding that encoding is used.
      * <p>
      * Else 'UTF-8' is used.
      * <p>
      * If lenient detection is indicated an XmlStreamReaderException is never thrown.
      * <p>
      * 
      * @param is
      *            InputStream to create the reader from.
      * @param httpContentType
      *            content-type header to use for the resolution of the charset encoding.
      * @param lenient
      *            indicates if the charset encoding detection should be relaxed.
      * @throws IOException
      *             thrown if there is a problem reading the file.
      * @throws XmlStreamReaderException
      *             thrown if the charset encoding could not be determined according to the specs.
      * 
      */
     public XmlReader( InputStream is, String httpContentType, boolean lenient, String defaultEncoding )
         throws IOException, XmlStreamReaderException
     {
         _defaultEncoding = ( defaultEncoding == null ) ? _staticDefaultEncoding : defaultEncoding;
         try
         {
             doHttpStream( is, httpContentType, lenient );
         }
         catch ( XmlStreamReaderException ex )
         {
             if ( !lenient )
             {
                 throw ex;
             }
             else
             {
                 doLenientDetection( httpContentType, ex );
             }
         }
     }
 
     /**
      * Creates a Reader using an InputStream an the associated content-type header. This constructor is lenient
      * regarding the encoding detection.
      * <p>
      * First it checks if the stream has BOM. If there is not BOM checks the content-type encoding. If there is not
      * content-type encoding checks the XML prolog encoding. If there is not XML prolog encoding uses the default
      * encoding mandated by the content-type MIME type.
      * <p>
      * If lenient detection is indicated and the detection above fails as per specifications it then attempts the
      * following:
      * <p>
      * If the content type was 'text/html' it replaces it with 'text/xml' and tries the detection again.
      * <p>
      * Else if the XML prolog had a charset encoding that encoding is used.
      * <p>
      * Else if the content type had a charset encoding that encoding is used.
      * <p>
      * Else 'UTF-8' is used.
      * <p>
      * If lenient detection is indicated an XmlStreamReaderException is never thrown.
      * <p>
      * 
      * @param is
      *            InputStream to create the reader from.
      * @param httpContentType
      *            content-type header to use for the resolution of the charset encoding.
      * @param lenient
      *            indicates if the charset encoding detection should be relaxed.
      * @throws IOException
      *             thrown if there is a problem reading the file.
      * @throws XmlStreamReaderException
      *             thrown if the charset encoding could not be determined according to the specs.
      * 
      */
     public XmlReader( InputStream is, String httpContentType, boolean lenient ) throws IOException, XmlStreamReaderException
     {
         this( is, httpContentType, lenient, null );
     }
 
     private void doLenientDetection( String httpContentType, XmlStreamReaderException ex ) throws IOException
     {
         if ( httpContentType != null )
         {
             if ( httpContentType.startsWith( "text/html" ) )
             {
                 httpContentType = httpContentType.substring( "text/html".length() );
                 httpContentType = "text/xml" + httpContentType;
                 try
                 {
                     doHttpStream( ex.getInputStream(), httpContentType, true );
                     ex = null;
                 }
                 catch ( XmlStreamReaderException ex2 )
                 {
                     ex = ex2;
                 }
             }
         }
         if ( ex != null )
         {
             String encoding = ex.getXmlEncoding();
             if ( encoding == null )
             {
                 encoding = ex.getContentTypeEncoding();
             }
             if ( encoding == null )
             {
                 encoding = ( _defaultEncoding == null ) ? UTF_8 : _defaultEncoding;
             }
             prepareReader( ex.getInputStream(), encoding );
         }
     }
 
     /**
      * Returns the charset encoding of the XmlReader.
      * <p>
      * 
      * @return charset encoding.
      * 
      */
     public String getEncoding()
     {
         return _encoding;
     }
 
     public int read( char[] buf, int offset, int len ) throws IOException
     {
         return _reader.read( buf, offset, len );
     }
 
     /**
      * Closes the XmlReader stream.
      * <p>
      * 
      * @throws IOException
      *             thrown if there was a problem closing the stream.
      * 
      */
     public void close() throws IOException
     {
         _reader.close();
     }
 
     private void doRawStream( InputStream is, boolean lenient ) throws IOException
     {
         BufferedInputStream pis = new BufferedInputStream( is, BUFFER_SIZE );
         String bomEnc = getBOMEncoding( pis );
         String xmlGuessEnc = getXMLGuessEncoding( pis );
         String xmlEnc = getXmlProlog( pis, xmlGuessEnc );
         String encoding = calculateRawEncoding( bomEnc, xmlGuessEnc, xmlEnc, pis );
         prepareReader( pis, encoding );
     }
 
     private void doHttpStream( InputStream is, String httpContentType, boolean lenient ) throws IOException
     {
         BufferedInputStream pis = new BufferedInputStream( is, BUFFER_SIZE );
         String cTMime = getContentTypeMime( httpContentType );
         String cTEnc = getContentTypeEncoding( httpContentType );
         String bomEnc = getBOMEncoding( pis );
         String xmlGuessEnc = getXMLGuessEncoding( pis );
         String xmlEnc = getXmlProlog( pis, xmlGuessEnc );
         String encoding = calculateHttpEncoding( cTMime, cTEnc, bomEnc, xmlGuessEnc, xmlEnc, pis, lenient );
         prepareReader( pis, encoding );
     }
 
     private void prepareReader( InputStream is, String encoding ) throws IOException
     {
         _reader = new InputStreamReader( is, encoding );
         _encoding = encoding;
     }
 
     // InputStream is passed for XmlStreamReaderException creation only
     private String calculateRawEncoding( String bomEnc, String xmlGuessEnc, String xmlEnc, InputStream is )
         throws IOException
     {
         String encoding;
         if ( bomEnc == null )
         {
             if ( xmlGuessEnc == null || xmlEnc == null )
             {
                 encoding = ( _defaultEncoding == null ) ? UTF_8 : _defaultEncoding;
             }
             else if ( xmlEnc.equals( UTF_16 ) && ( xmlGuessEnc.equals( UTF_16BE ) || xmlGuessEnc.equals( UTF_16LE ) ) )
             {
                 encoding = xmlGuessEnc;
             }
             else
             {
                 encoding = xmlEnc;
             }
         }
         else if ( bomEnc.equals( UTF_8 ) )
         {
             if ( xmlGuessEnc != null && !xmlGuessEnc.equals( UTF_8 ) )
             {
                 throw new XmlStreamReaderException( RAW_EX_1.format( new Object[] { bomEnc, xmlGuessEnc, xmlEnc } ), bomEnc,
                                               xmlGuessEnc, xmlEnc, is );
             }
             if ( xmlEnc != null && !xmlEnc.equals( UTF_8 ) )
             {
                 throw new XmlStreamReaderException( RAW_EX_1.format( new Object[] { bomEnc, xmlGuessEnc, xmlEnc } ), bomEnc,
                                               xmlGuessEnc, xmlEnc, is );
             }
             encoding = UTF_8;
         }
         else if ( bomEnc.equals( UTF_16BE ) || bomEnc.equals( UTF_16LE ) )
         {
             if ( xmlGuessEnc != null && !xmlGuessEnc.equals( bomEnc ) )
             {
                 throw new IOException( RAW_EX_1.format( new Object[] { bomEnc, xmlGuessEnc, xmlEnc } ) );
             }
             if ( xmlEnc != null && !xmlEnc.equals( UTF_16 ) && !xmlEnc.equals( bomEnc ) )
             {
                 throw new XmlStreamReaderException( RAW_EX_1.format( new Object[] { bomEnc, xmlGuessEnc, xmlEnc } ), bomEnc,
                                               xmlGuessEnc, xmlEnc, is );
             }
             encoding = bomEnc;
         }
         else
         {
             throw new XmlStreamReaderException( RAW_EX_2.format( new Object[] { bomEnc, xmlGuessEnc, xmlEnc } ), bomEnc,
                                           xmlGuessEnc, xmlEnc, is );
         }
         return encoding;
     }
 
     // InputStream is passed for XmlStreamReaderException creation only
     private String calculateHttpEncoding( String cTMime, String cTEnc, String bomEnc, String xmlGuessEnc,
                                           String xmlEnc, InputStream is, boolean lenient ) throws IOException
     {
         String encoding;
         if ( lenient & xmlEnc != null )
         {
             encoding = xmlEnc;
         }
         else
         {
             boolean appXml = isAppXml( cTMime );
             boolean textXml = isTextXml( cTMime );
             if ( appXml || textXml )
             {
                 if ( cTEnc == null )
                 {
                     if ( appXml )
                     {
                         encoding = calculateRawEncoding( bomEnc, xmlGuessEnc, xmlEnc, is );
                     }
                     else
                     {
                         encoding = ( _defaultEncoding == null ) ? US_ASCII : _defaultEncoding;
                     }
                 }
                 else if ( bomEnc != null && ( cTEnc.equals( UTF_16BE ) || cTEnc.equals( UTF_16LE ) ) )
                 {
                     throw new XmlStreamReaderException( HTTP_EX_1.format( new Object[] { cTMime, cTEnc, bomEnc, xmlGuessEnc,
                         xmlEnc } ), cTMime, cTEnc, bomEnc, xmlGuessEnc, xmlEnc, is );
                 }
                 else if ( cTEnc.equals( UTF_16 ) )
                 {
                     if ( bomEnc != null && bomEnc.startsWith( UTF_16 ) )
                     {
                         encoding = bomEnc;
                     }
                     else
                     {
                         throw new XmlStreamReaderException( HTTP_EX_2.format( new Object[] { cTMime, cTEnc, bomEnc,
                             xmlGuessEnc, xmlEnc } ), cTMime, cTEnc, bomEnc, xmlGuessEnc, xmlEnc, is );
                     }
                 }
                 else
                 {
                     encoding = cTEnc;
                 }
             }
             else
             {
                 throw new XmlStreamReaderException( HTTP_EX_3.format( new Object[] { cTMime, cTEnc, bomEnc, xmlGuessEnc,
                     xmlEnc } ), cTMime, cTEnc, bomEnc, xmlGuessEnc, xmlEnc, is );
             }
         }
         return encoding;
     }
 
     // returns MIME type or NULL if httpContentType is NULL
     private static String getContentTypeMime( String httpContentType )
     {
         String mime = null;
         if ( httpContentType != null )
         {
             int i = httpContentType.indexOf( ";" );
             mime = ( ( i == -1 ) ? httpContentType : httpContentType.substring( 0, i ) ).trim();
         }
         return mime;
     }
 
     private static final Pattern CHARSET_PATTERN = Pattern.compile( "charset=([.[^; ]]*)" );
 
     // returns charset parameter value, NULL if not present, NULL if httpContentType is NULL
     private static String getContentTypeEncoding( String httpContentType )
     {
         String encoding = null;
         if ( httpContentType != null )
         {
             int i = httpContentType.indexOf( ";" );
             if ( i > -1 )
             {
                 String postMime = httpContentType.substring( i + 1 );
                 Matcher m = CHARSET_PATTERN.matcher( postMime );
                 encoding = ( m.find() ) ? m.group( 1 ) : null;
                 encoding = ( encoding != null ) ? encoding.toUpperCase() : null;
             }
         }
         return encoding;
     }
 
     // returns the BOM in the stream, NULL if not present,
     // if there was BOM the in the stream it is consumed
     private static String getBOMEncoding( BufferedInputStream is ) throws IOException
     {
         String encoding = null;
         int[] bytes = new int[3];
         is.mark( 3 );
         bytes[0] = is.read();
         bytes[1] = is.read();
         bytes[2] = is.read();
 
         if ( bytes[0] == 0xFE && bytes[1] == 0xFF )
         {
             encoding = UTF_16BE;
             is.reset();
             is.read();
             is.read();
         }
         else if ( bytes[0] == 0xFF && bytes[1] == 0xFE )
         {
             encoding = UTF_16LE;
             is.reset();
             is.read();
             is.read();
         }
         else if ( bytes[0] == 0xEF && bytes[1] == 0xBB && bytes[2] == 0xBF )
         {
             encoding = UTF_8;
         }
         else
         {
             is.reset();
         }
         return encoding;
     }
 
     // returns the best guess for the encoding by looking the first bytes of the stream, '<?'
     private static String getXMLGuessEncoding( BufferedInputStream is ) throws IOException
     {
         String encoding = null;
         int[] bytes = new int[4];
         is.mark( 4 );
         bytes[0] = is.read();
         bytes[1] = is.read();
         bytes[2] = is.read();
         bytes[3] = is.read();
         is.reset();
 
         if ( bytes[0] == 0x00 && bytes[1] == 0x3C && bytes[2] == 0x00 && bytes[3] == 0x3F )
         {
             encoding = UTF_16BE;
         }
         else if ( bytes[0] == 0x3C && bytes[1] == 0x00 && bytes[2] == 0x3F && bytes[3] == 0x00 )
         {
             encoding = UTF_16LE;
         }
         else if ( bytes[0] == 0x3C && bytes[1] == 0x3F && bytes[2] == 0x78 && bytes[3] == 0x6D )
         {
             encoding = UTF_8;
         }
         else if ( bytes[0] == 0x4C && bytes[1] == 0x6F && bytes[2] == 0xA7 && bytes[3] == 0x94 )
         {
             encoding = EBCDIC;
         }
         return encoding;
     }
 
     static final Pattern ENCODING_PATTERN =
         Pattern.compile( "<\\?xml.*encoding[\\s]*=[\\s]*((?:\".[^\"]*\")|(?:'.[^']*'))", Pattern.MULTILINE );
 
     // returns the encoding declared in the <?xml encoding=...?>, NULL if none
     private static String getXmlProlog( BufferedInputStream is, String guessedEnc ) throws IOException
     {
         String encoding = null;
         if ( guessedEnc != null )
         {
             byte[] bytes = new byte[BUFFER_SIZE];
             is.mark( BUFFER_SIZE );
             int offset = 0;
             int max = BUFFER_SIZE;
             int c = is.read( bytes, offset, max );
             int firstGT = -1;
             String xmlProlog = null;
             while ( c != -1 && firstGT == -1 && offset < BUFFER_SIZE )
             {
                 offset += c;
                 max -= c;
                 c = is.read( bytes, offset, max );
                 xmlProlog = new String( bytes, 0, offset, guessedEnc );
                 firstGT = xmlProlog.indexOf( '>' );
             }
             if ( firstGT == -1 )
             {
                 if ( c == -1 )
                 {
                     throw new IOException( "Unexpected end of XML stream" );
                 }
                 else
                 {
                     throw new IOException( "XML prolog or ROOT element not found on first " + offset + " bytes" );
                 }
             }
             int bytesRead = offset;
             if ( bytesRead > 0 )
             {
                 is.reset();
                 BufferedReader bReader = new BufferedReader( new StringReader( xmlProlog.substring( 0, firstGT + 1 ) ) );
                 StringBuffer prolog = new StringBuffer();
                 String line = bReader.readLine();
                 while ( line != null )
                 {
                     prolog.append( line );
                     line = bReader.readLine();
                 }
                 Matcher m = ENCODING_PATTERN.matcher( prolog );
                 if ( m.find() )
                 {
                     encoding = m.group( 1 ).toUpperCase();
                     encoding = encoding.substring( 1, encoding.length() - 1 );
                 }
             }
         }
         return encoding;
     }
 
     // indicates if the MIME type belongs to the APPLICATION XML family
     private static boolean isAppXml( String mime )
     {
         return mime != null
                         && ( mime.equals( "application/xml" ) || mime.equals( "application/xml-dtd" )
                                         || mime.equals( "application/xml-external-parsed-entity" ) || ( mime.startsWith( "application/" ) && mime.endsWith( "+xml" ) ) );
     }
 
     // indicates if the MIME type belongs to the TEXT XML family
     private static boolean isTextXml( String mime )
     {
         return mime != null
                         && ( mime.equals( "text/xml" ) || mime.equals( "text/xml-external-parsed-entity" ) || ( mime.startsWith( "text/" ) && mime.endsWith( "+xml" ) ) );
     }
 
     private static final MessageFormat RAW_EX_1 =
         new MessageFormat( "Invalid encoding, BOM [{0}] XML guess [{1}] XML prolog [{2}] encoding mismatch" );
 
     private static final MessageFormat RAW_EX_2 =
         new MessageFormat( "Invalid encoding, BOM [{0}] XML guess [{1}] XML prolog [{2}] unknown BOM" );
 
     private static final MessageFormat HTTP_EX_1 =
         new MessageFormat(
                            "Invalid encoding, CT-MIME [{0}] CT-Enc [{1}] BOM [{2}] XML guess [{3}] XML prolog [{4}], BOM must be NULL" );
 
     private static final MessageFormat HTTP_EX_2 =
         new MessageFormat(
                            "Invalid encoding, CT-MIME [{0}] CT-Enc [{1}] BOM [{2}] XML guess [{3}] XML prolog [{4}], encoding mismatch" );
 
     private static final MessageFormat HTTP_EX_3 =
         new MessageFormat(
                            "Invalid encoding, CT-MIME [{0}] CT-Enc [{1}] BOM [{2}] XML guess [{3}] XML prolog [{4}], Invalid MIME" );
 
 }