Java Tutorial/XML/XML Reader

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Read Xml from InputStream and return Document

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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.
 */
import java.io.IOException;
import java.io.InputStream;
import java.io.StringReader;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.stream.StreamSource;
import org.w3c.dom.Document;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
/**
 * Few simple utils to read DOM. This is originally from the Jakarta Commons
 * Modeler.
 * 
 * @author Costin Manolache
 */
public class Utils {
  /**
   * Read XML as DOM.
   */
  public static Document readXml(InputStream is) throws SAXException, IOException,
      ParserConfigurationException {
      DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
      dbf.setValidating(false);
      dbf.setIgnoringComments(false);
      dbf.setIgnoringElementContentWhitespace(true);
      dbf.setNamespaceAware(true);
      // dbf.setCoalescing(true);
      // dbf.setExpandEntityReferences(true);
      DocumentBuilder db = null;
      db = dbf.newDocumentBuilder();
      db.setEntityResolver(new NullResolver());
      // db.setErrorHandler( new MyErrorHandler());
      return db.parse(is);
  }
}
class NullResolver implements EntityResolver {
  public InputSource resolveEntity(String publicId, String systemId) throws SAXException,
      IOException {
    return new InputSource(new StringReader(""));
  }
}





Read Xml from Reader and return Document

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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.
 */
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.io.StringReader;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.stream.StreamSource;
import org.w3c.dom.Document;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
/**
 * Few simple utils to read DOM. This is originally from the Jakarta Commons
 * Modeler.
 * 
 * @author Costin Manolache
 */
public class Utils {
  public static Document readXml(Reader is) throws SAXException, IOException, ParserConfigurationException {
    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    dbf.setValidating(false);
    dbf.setIgnoringComments(false);
    dbf.setIgnoringElementContentWhitespace(true);
    dbf.setNamespaceAware(true);
    // dbf.setCoalescing(true);
    // dbf.setExpandEntityReferences(true);
    DocumentBuilder db = null;
    db = dbf.newDocumentBuilder();
    db.setEntityResolver(new NullResolver());
    // db.setErrorHandler( new MyErrorHandler());
    InputSource ips = new InputSource(is);
    return db.parse(ips);
}
}
class NullResolver implements EntityResolver {
  public InputSource resolveEntity(String publicId, String systemId) throws SAXException,
      IOException {
    return new InputSource(new StringReader(""));
  }
}





Sniffed Xml InputStream to find out the declaration and file encoding

/*   Copyright 2004 The Apache Software Foundation
 *
 *   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.
 */
// revised from xmlbeans
import java.io.InputStream;
import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.ByteArrayInputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.nio.charset.Charset;
public class SniffedXmlInputStream extends BufferedInputStream
{
    // We don"t sniff more than 192 bytes.
    public static int MAX_SNIFFED_BYTES = 192;
    public SniffedXmlInputStream(InputStream stream) throws IOException
    {
        super(stream);
        // read byte order marks and detect EBCDIC etc
        _encoding = sniffFourBytes();
        if (_encoding != null && _encoding.equals("IBM037"))
        {
            // First four bytes suggest EBCDIC with <?xm at start
            String encoding = sniffForXmlDecl(_encoding);
            if (encoding != null)
                _encoding = encoding;
        }
        if (_encoding == null)
        {
            // Haven"t yet determined encoding: sniff for <?xml encoding="..."?>
            // assuming we can read it as UTF-8.
            _encoding = sniffForXmlDecl("UTF-8");
        }
        if (_encoding == null)
        {
            // The XML spec says these two things:
            // (1) "In the absence of external character encoding information
            // (such as MIME headers), parsed entities which are stored in an
            // encoding other than UTF-8 or UTF-16 must begin with a text
            // declaration (see 4.3.1 The Text Declaration) containing an
            // encoding declaration:"
            // (2) "In the absence of information provided by an external
            // transport protocol (e.g. HTTP or MIME), it is an error
            // for an entity including an encoding declaration to be
            // presented to the XML processor in an encoding other than
            // that named in the declaration, or for an entity which begins
            // with neither a Byte Order Mark nor an encoding declaration
            // to use an encoding other than UTF-8."
            // Since we"re using a sniffed stream, we do not have external
            // character encoding information.
            // Since we"re here, we also don"t have a recognized byte order
            // mark or an explicit encoding declaration that can be read in
            // either ASCII or EBDIC style.
            // Therefore, we must use UTF-8.
            _encoding = "UTF-8";
        }
    }
    private int readAsMuchAsPossible(byte[] buf, int startAt, int len) throws IOException
    {
        int total = 0;
        while (total < len)
        {
            int count = read(buf, startAt + total, len - total);
            if (count < 0)
                break;
            total += count;
        }
        return total;
    }
    private String sniffFourBytes() throws IOException
    {
        mark(4);
        int skip = 0;
        try
        {
            byte[] buf = new byte[4];
            if (readAsMuchAsPossible(buf, 0, 4) < 4)
                return null;
            long result = 0xFF000000 & (buf[0] << 24) | 0x00FF0000 & (buf[1] << 16) | 0x0000FF00 & (buf[2] << 8) | 0x000000FF & buf[3];
            if (result == 0x0000FEFF)
                return "UCS-4";
            else if (result == 0xFFFE0000)
                return "UCS-4";
            else if (result == 0x0000003C)
                return "UCS-4BE";
            else if (result == 0x3C000000)
                return "UCS-4LE";
            else if (result == 0x003C003F)
                return "UTF-16BE";
            else if (result == 0x3C003F00)
                return "UTF-16LE";
            else if (result == 0x3C3F786D)
                return null; // looks like US-ASCII with <?xml: sniff
            else if (result == 0x4C6FA794)
                return "IBM037"; // Sniff for ebdic codepage
            else if ((result & 0xFFFF0000) == 0xFEFF0000)
                return "UTF-16";
            else if ((result & 0xFFFF0000) == 0xFFFE0000)
                return "UTF-16";
            else if ((result & 0xFFFFFF00) == 0xEFBBBF00)
                return "UTF-8";
            else return null;
        }
        finally
        {
            reset();
        }
    }
    // BUGBUG in JDK: Charset.forName is not threadsafe, so we"ll prime it
    // with the common charsets.
    private static Charset dummy1 = Charset.forName("UTF-8");
    private static Charset dummy2 = Charset.forName("UTF-16");
    private static Charset dummy3 = Charset.forName("UTF-16BE");
    private static Charset dummy4 = Charset.forName("UTF-16LE");
    private static Charset dummy5 = Charset.forName("ISO-8859-1");
    private static Charset dummy6 = Charset.forName("US-ASCII");
    private static Charset dummy7 = Charset.forName("Cp1252");

    private String sniffForXmlDecl(String encoding) throws IOException
    {
        mark(MAX_SNIFFED_BYTES);
        try
        {
            byte[] bytebuf = new byte[MAX_SNIFFED_BYTES];
            int bytelimit = readAsMuchAsPossible(bytebuf, 0, MAX_SNIFFED_BYTES);
            // BUGBUG in JDK: Charset.forName is not threadsafe.
            Charset charset = Charset.forName(encoding);
            Reader reader = new InputStreamReader(new ByteArrayInputStream(bytebuf, 0, bytelimit), charset);
            char[] buf = new char[bytelimit];
            int limit = 0;
            while (limit < bytelimit)
            {
                int count = reader.read(buf, limit, bytelimit - limit);
                if (count < 0)
                    break;
                limit += count;
            }
            return extractXmlDeclEncoding(buf, 0, limit);
        }
        finally
        {
            reset();
        }
    }
    private String _encoding;
    public String getXmlEncoding()
    {
        return _encoding;
    }
    /* package */ static String extractXmlDeclEncoding(char[] buf, int offset, int size)
    {
        int limit = offset + size;
        int xmlpi = firstIndexOf("<?xml", buf, offset, limit);
        if (xmlpi >= 0)
        {
            int i = xmlpi + 5;
            ScannedAttribute attr = new ScannedAttribute();
            while (i < limit)
            {
                i = scanAttribute(buf, i, limit, attr);
                if (i < 0)
                    return null;
                if (attr.name.equals("encoding"))
                    return attr.value;
            }
        }
        return null;
    }
    private static int firstIndexOf(String s, char[] buf, int startAt, int limit)
    {
        assert(s.length() > 0);
        char[] lookFor = s.toCharArray();
        char firstchar = lookFor[0];
        searching: for (limit -= lookFor.length; startAt < limit; startAt++)
        {
            if (buf[startAt] == firstchar)
            {
                for (int i = 1; i < lookFor.length; i++)
                {
                    if (buf[startAt + i] != lookFor[i])
                    {
                        continue searching;
                    }
                }
                return startAt;
            }
        }
        return -1;
    }
    private static int nextNonmatchingByte(char[] lookFor, char[] buf, int startAt, int limit)
    {
        searching: for (; startAt < limit; startAt++)
        {
            int thischar = buf[startAt];
            for (int i = 0; i < lookFor.length; i++)
                if (thischar == lookFor[i])
                    continue searching;
            return startAt;
        }
        return -1;
    }
    private static int nextMatchingByte(char[] lookFor, char[] buf, int startAt, int limit)
    {
        searching: for (; startAt < limit; startAt++)
        {
            int thischar = buf[startAt];
            for (int i = 0; i < lookFor.length; i++)
                if (thischar == lookFor[i])
                    return startAt;
        }
        return -1;
    }
    private static int nextMatchingByte(char lookFor, char[] buf, int startAt, int limit)
    {
        searching: for (; startAt < limit; startAt++)
        {
            if (buf[startAt] == lookFor)
                return startAt;
        }
        return -1;
    }
    private static char[] WHITESPACE = new char[] { " ", "\r", "\t", "\n" };
    private static char[] NOTNAME = new char[] { "=", " ", "\r", "\t", "\n", "?", ">", "<", "\"", "\"" };
    private static class ScannedAttribute
    {
        public String name;
        public String value;
    }
    private static int scanAttribute(char[] buf, int startAt, int limit, ScannedAttribute attr)
    {
        int nameStart = nextNonmatchingByte(WHITESPACE, buf, startAt, limit);
        if (nameStart < 0)
            return -1;
        int nameEnd = nextMatchingByte(NOTNAME, buf, nameStart, limit);
        if (nameEnd < 0)
            return -1;
        int equals = nextNonmatchingByte(WHITESPACE, buf, nameEnd, limit);
        if (equals < 0)
            return -1;
        if (buf[equals] != "=")
            return -1;
        int valQuote = nextNonmatchingByte(WHITESPACE, buf, equals + 1, limit);
        if (buf[valQuote] != "\"" && buf[valQuote] != "\"")
            return -1;
        int valEndquote = nextMatchingByte(buf[valQuote], buf, valQuote + 1, limit);
        if (valEndquote < 0)
            return -1;
        attr.name = new String(buf, nameStart, nameEnd - nameStart);
        attr.value = new String(buf, valQuote + 1, valEndquote - valQuote - 1);
        return valEndquote + 1;
    }
}





Sniffed Xml Reader

/*   Copyright 2004 The Apache Software Foundation
 *
 *   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.
 */
// revised from xml beans
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.nio.charset.Charset;
public class SniffedXmlReader extends BufferedReader {
  // We don"t sniff more than 192 bytes.
  public static int MAX_SNIFFED_CHARS = 192;
  public SniffedXmlReader(Reader reader) throws IOException {
    super(reader);
    _encoding = sniffForXmlDecl();
  }
  private int readAsMuchAsPossible(char[] buf, int startAt, int len) throws IOException {
    int total = 0;
    while (total < len) {
      int count = read(buf, startAt + total, len - total);
      if (count < 0)
        break;
      total += count;
    }
    return total;
  }
  // BUGBUG in JDK: Charset.forName is not threadsafe, so we"ll prime it
  // with the common charsets.
  private static Charset dummy1 = Charset.forName("UTF-8");
  private static Charset dummy2 = Charset.forName("UTF-16");
  private static Charset dummy3 = Charset.forName("UTF-16BE");
  private static Charset dummy4 = Charset.forName("UTF-16LE");
  private static Charset dummy5 = Charset.forName("ISO-8859-1");
  private static Charset dummy6 = Charset.forName("US-ASCII");
  private static Charset dummy7 = Charset.forName("Cp1252");
  private String sniffForXmlDecl() throws IOException {
    mark(MAX_SNIFFED_CHARS);
    try {
      char[] buf = new char[MAX_SNIFFED_CHARS];
      int limit = readAsMuchAsPossible(buf, 0, MAX_SNIFFED_CHARS);
      return SniffedXmlInputStream.extractXmlDeclEncoding(buf, 0, limit);
    } finally {
      reset();
    }
  }
  private String _encoding;
  public String getXmlEncoding() {
    return _encoding;
  }
}
class SniffedXmlInputStream extends BufferedInputStream
{
    // We don"t sniff more than 192 bytes.
    public static int MAX_SNIFFED_BYTES = 192;
    public SniffedXmlInputStream(InputStream stream) throws IOException
    {
        super(stream);
        // read byte order marks and detect EBCDIC etc
        _encoding = sniffFourBytes();
        if (_encoding != null && _encoding.equals("IBM037"))
        {
            // First four bytes suggest EBCDIC with <?xm at start
            String encoding = sniffForXmlDecl(_encoding);
            if (encoding != null)
                _encoding = encoding;
        }
        if (_encoding == null)
        {
            // Haven"t yet determined encoding: sniff for <?xml encoding="..."?>
            // assuming we can read it as UTF-8.
            _encoding = sniffForXmlDecl("UTF-8");
        }
        if (_encoding == null)
        {
            // The XML spec says these two things:
            // (1) "In the absence of external character encoding information
            // (such as MIME headers), parsed entities which are stored in an
            // encoding other than UTF-8 or UTF-16 must begin with a text
            // declaration (see 4.3.1 The Text Declaration) containing an
            // encoding declaration:"
            // (2) "In the absence of information provided by an external
            // transport protocol (e.g. HTTP or MIME), it is an error
            // for an entity including an encoding declaration to be
            // presented to the XML processor in an encoding other than
            // that named in the declaration, or for an entity which begins
            // with neither a Byte Order Mark nor an encoding declaration
            // to use an encoding other than UTF-8."
            // Since we"re using a sniffed stream, we do not have external
            // character encoding information.
            // Since we"re here, we also don"t have a recognized byte order
            // mark or an explicit encoding declaration that can be read in
            // either ASCII or EBDIC style.
            // Therefore, we must use UTF-8.
            _encoding = "UTF-8";
        }
    }
    private int readAsMuchAsPossible(byte[] buf, int startAt, int len) throws IOException
    {
        int total = 0;
        while (total < len)
        {
            int count = read(buf, startAt + total, len - total);
            if (count < 0)
                break;
            total += count;
        }
        return total;
    }
    private String sniffFourBytes() throws IOException
    {
        mark(4);
        int skip = 0;
        try
        {
            byte[] buf = new byte[4];
            if (readAsMuchAsPossible(buf, 0, 4) < 4)
                return null;
            long result = 0xFF000000 & (buf[0] << 24) | 0x00FF0000 & (buf[1] << 16) | 0x0000FF00 & (buf[2] << 8) | 0x000000FF & buf[3];
            if (result == 0x0000FEFF)
                return "UCS-4";
            else if (result == 0xFFFE0000)
                return "UCS-4";
            else if (result == 0x0000003C)
                return "UCS-4BE";
            else if (result == 0x3C000000)
                return "UCS-4LE";
            else if (result == 0x003C003F)
                return "UTF-16BE";
            else if (result == 0x3C003F00)
                return "UTF-16LE";
            else if (result == 0x3C3F786D)
                return null; // looks like US-ASCII with <?xml: sniff
            else if (result == 0x4C6FA794)
                return "IBM037"; // Sniff for ebdic codepage
            else if ((result & 0xFFFF0000) == 0xFEFF0000)
                return "UTF-16";
            else if ((result & 0xFFFF0000) == 0xFFFE0000)
                return "UTF-16";
            else if ((result & 0xFFFFFF00) == 0xEFBBBF00)
                return "UTF-8";
            else return null;
        }
        finally
        {
            reset();
        }
    }
    // BUGBUG in JDK: Charset.forName is not threadsafe, so we"ll prime it
    // with the common charsets.
    private static Charset dummy1 = Charset.forName("UTF-8");
    private static Charset dummy2 = Charset.forName("UTF-16");
    private static Charset dummy3 = Charset.forName("UTF-16BE");
    private static Charset dummy4 = Charset.forName("UTF-16LE");
    private static Charset dummy5 = Charset.forName("ISO-8859-1");
    private static Charset dummy6 = Charset.forName("US-ASCII");
    private static Charset dummy7 = Charset.forName("Cp1252");

    private String sniffForXmlDecl(String encoding) throws IOException
    {
        mark(MAX_SNIFFED_BYTES);
        try
        {
            byte[] bytebuf = new byte[MAX_SNIFFED_BYTES];
            int bytelimit = readAsMuchAsPossible(bytebuf, 0, MAX_SNIFFED_BYTES);
            // BUGBUG in JDK: Charset.forName is not threadsafe.
            Charset charset = Charset.forName(encoding);
            Reader reader = new InputStreamReader(new ByteArrayInputStream(bytebuf, 0, bytelimit), charset);
            char[] buf = new char[bytelimit];
            int limit = 0;
            while (limit < bytelimit)
            {
                int count = reader.read(buf, limit, bytelimit - limit);
                if (count < 0)
                    break;
                limit += count;
            }
            return extractXmlDeclEncoding(buf, 0, limit);
        }
        finally
        {
            reset();
        }
    }
    private String _encoding;
    public String getXmlEncoding()
    {
        return _encoding;
    }
    /* package */ static String extractXmlDeclEncoding(char[] buf, int offset, int size)
    {
        int limit = offset + size;
        int xmlpi = firstIndexOf("<?xml", buf, offset, limit);
        if (xmlpi >= 0)
        {
            int i = xmlpi + 5;
            ScannedAttribute attr = new ScannedAttribute();
            while (i < limit)
            {
                i = scanAttribute(buf, i, limit, attr);
                if (i < 0)
                    return null;
                if (attr.name.equals("encoding"))
                    return attr.value;
            }
        }
        return null;
    }
    private static int firstIndexOf(String s, char[] buf, int startAt, int limit)
    {
        assert(s.length() > 0);
        char[] lookFor = s.toCharArray();
        char firstchar = lookFor[0];
        searching: for (limit -= lookFor.length; startAt < limit; startAt++)
        {
            if (buf[startAt] == firstchar)
            {
                for (int i = 1; i < lookFor.length; i++)
                {
                    if (buf[startAt + i] != lookFor[i])
                    {
                        continue searching;
                    }
                }
                return startAt;
            }
        }
        return -1;
    }
    private static int nextNonmatchingByte(char[] lookFor, char[] buf, int startAt, int limit)
    {
        searching: for (; startAt < limit; startAt++)
        {
            int thischar = buf[startAt];
            for (int i = 0; i < lookFor.length; i++)
                if (thischar == lookFor[i])
                    continue searching;
            return startAt;
        }
        return -1;
    }
    private static int nextMatchingByte(char[] lookFor, char[] buf, int startAt, int limit)
    {
        searching: for (; startAt < limit; startAt++)
        {
            int thischar = buf[startAt];
            for (int i = 0; i < lookFor.length; i++)
                if (thischar == lookFor[i])
                    return startAt;
        }
        return -1;
    }
    private static int nextMatchingByte(char lookFor, char[] buf, int startAt, int limit)
    {
        searching: for (; startAt < limit; startAt++)
        {
            if (buf[startAt] == lookFor)
                return startAt;
        }
        return -1;
    }
    private static char[] WHITESPACE = new char[] { " ", "\r", "\t", "\n" };
    private static char[] NOTNAME = new char[] { "=", " ", "\r", "\t", "\n", "?", ">", "<", "\"", "\"" };
    private static class ScannedAttribute
    {
        public String name;
        public String value;
    }
    private static int scanAttribute(char[] buf, int startAt, int limit, ScannedAttribute attr)
    {
        int nameStart = nextNonmatchingByte(WHITESPACE, buf, startAt, limit);
        if (nameStart < 0)
            return -1;
        int nameEnd = nextMatchingByte(NOTNAME, buf, nameStart, limit);
        if (nameEnd < 0)
            return -1;
        int equals = nextNonmatchingByte(WHITESPACE, buf, nameEnd, limit);
        if (equals < 0)
            return -1;
        if (buf[equals] != "=")
            return -1;
        int valQuote = nextNonmatchingByte(WHITESPACE, buf, equals + 1, limit);
        if (buf[valQuote] != "\"" && buf[valQuote] != "\"")
            return -1;
        int valEndquote = nextMatchingByte(buf[valQuote], buf, valQuote + 1, limit);
        if (valEndquote < 0)
            return -1;
        attr.name = new String(buf, nameStart, nameEnd - nameStart);
        attr.value = new String(buf, valQuote + 1, valEndquote - valQuote - 1);
        return valEndquote + 1;
    }
}





Xml Encoding Sniffer

/*   Copyright 2004 The Apache Software Foundation
 *
 *   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.
 */
// Revised from xml beans
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.nio.charset.Charset;
import com.sun.org.apache.xerces.internal.util.EncodingMap;
public class XmlEncodingSniffer
{
    private String      _xmlencoding;
    private String      _javaencoding;
    private InputStream _stream;
    private Reader      _reader;
    /**
     * Sniffs the given XML stream for encoding information.
     *
     * After a sniffer is constructed, it can return either a stream
     * (which is a buffered stream wrapper of the original) or a reader
     * (which applies the proper encoding).
     *
     * @param stream           The stream to sniff
     * @param encodingOverride The XML (IANA) name for the overriding encoding
     * @throws IOException
     * @throws UnsupportedEncodingException
     */
    public XmlEncodingSniffer(InputStream stream, String encodingOverride)
        throws IOException, UnsupportedEncodingException
    {
        _stream = stream;
        
        if (encodingOverride != null)
            _xmlencoding = EncodingMap.getJava2IANAMapping(encodingOverride);
        if (_xmlencoding == null)
            _xmlencoding = encodingOverride;
        if (_xmlencoding == null)
        {
            SniffedXmlInputStream sniffed = new SniffedXmlInputStream(_stream);
            _xmlencoding = sniffed.getXmlEncoding();
            assert(_xmlencoding != null);
            _stream = sniffed;
        }
        _javaencoding = EncodingMap.getIANA2JavaMapping(_xmlencoding);
        
        // we allow you to use Java"s encoding names in XML even though you"re
        // not supposed to.
        
        if (_javaencoding == null)
            _javaencoding = _xmlencoding;
    }
    /**
     * Sniffs the given XML stream for encoding information.
     *
     * After a sniffer is constructed, it can return either a reader
     * (which is a buffered stream wrapper of the original) or a stream
     * (which applies the proper encoding).
     *
     * @param reader           The reader to sniff
     * @param encodingDefault  The Java name for the default encoding to apply, UTF-8 if null.
     * @throws IOException
     * @throws UnsupportedEncodingException
     */
    public XmlEncodingSniffer(Reader reader, String encodingDefault)
            throws IOException, UnsupportedEncodingException
    {
        if (encodingDefault == null)
            encodingDefault = "UTF-8";
        
        SniffedXmlReader sniffedReader = new SniffedXmlReader(reader);
        _reader = sniffedReader;
        _xmlencoding = sniffedReader.getXmlEncoding();
        if (_xmlencoding == null)
        {
            _xmlencoding = EncodingMap.getJava2IANAMapping(encodingDefault);
            if (_xmlencoding != null)
                _javaencoding = encodingDefault;
            else
                _xmlencoding = encodingDefault;
        }
        if (_xmlencoding == null)
            _xmlencoding = "UTF-8";
        
        // we allow you to use Java"s encoding names in XML even though you"re
        // not supposed to.
        
        _javaencoding = EncodingMap.getIANA2JavaMapping(_xmlencoding);
        
        if (_javaencoding == null)
            _javaencoding = _xmlencoding;
    }
    public String getXmlEncoding()
    {
        return _xmlencoding;
    }
    public String getJavaEncoding()
    {
        return _javaencoding;
    }
    public InputStream getStream()
            throws UnsupportedEncodingException
    {
        if (_stream != null)
        {
            InputStream is = _stream;
            _stream = null;
            return is;
        }
        if (_reader != null)
        {
            InputStream is = new ReaderInputStream( _reader, _javaencoding );
            _reader = null;
            return is;
        }
        return null;
    }

    public Reader getReader ( )
        throws UnsupportedEncodingException
    {
        if (_reader != null)
        {
            Reader reader = _reader;
            _reader = null;
            return reader;
        }
        if (_stream != null)
        {
            Reader reader = new InputStreamReader( _stream, _javaencoding );
            _stream = null;
            return reader;
        }
        return null;
    }
}
/*   Copyright 2004 The Apache Software Foundation
*
*   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.
*/
class ReaderInputStream extends PushedInputStream
{
   private Reader reader;
   private Writer writer;
   private char[] buf;
   public static int defaultBufferSize = 2048;
   public ReaderInputStream(Reader reader, String encoding) throws UnsupportedEncodingException
   {
       this(reader, encoding, defaultBufferSize);
   }
   public ReaderInputStream(Reader reader, String encoding, int bufferSize) throws UnsupportedEncodingException
   {
       if (bufferSize <= 0)
           throw new IllegalArgumentException("Buffer size <= 0");
       this.reader = reader;
       this.writer = new OutputStreamWriter(getOutputStream(), encoding);
       buf = new char[bufferSize];
   }
   public void fill(int requestedBytes) throws IOException
   {
       do
       {
           int chars = reader.read(buf);
           if (chars < 0)
               return;
           writer.write(buf, 0, chars);
           writer.flush();
       }
       while (available() <= 0); // loop for safety, in case encoding didn"t produce any bytes yet
   }
}
/*   Copyright 2004 The Apache Software Foundation
*
*   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.
*/
abstract class PushedInputStream extends InputStream
{
   private static int defaultBufferSize = 2048;
   protected byte buf[];
   protected int writepos;
   protected int readpos;
   protected int markpos = -1;
   protected int marklimit;
   protected OutputStream outputStream = new InternalOutputStream();
   /**
    * Called when more bytes need to be written into this stream
    * (as an OutputStream).
    *
    * This method must write at least one byte if the stream is
    * not ended, and it must not write any bytes if the stream has
    * already ended.
    */
   protected abstract void fill(int requestedBytes) throws IOException;
   /**
    * Returns the linked output stream.
    *
    * This is the output stream that must be written to whenever
    * the fill method is called.
    */
   public final OutputStream getOutputStream()
   {
       return outputStream;
   }
   public PushedInputStream()
   {
       this(defaultBufferSize);
   }
   public PushedInputStream(int size)
   {
       if (size < 0)
       {
           throw new IllegalArgumentException("Negative initial buffer size");
       }
       buf = new byte[size];
   }
   /**
    * Makes room for cb more bytes of data
    */
   private void shift(int cb)
   {
       int savepos = readpos;
       if (markpos > 0)
       {
           if (readpos - markpos > marklimit)
               markpos = -1;
           else
               savepos = markpos;
       }
       int size = writepos - savepos;
       if (savepos > 0 && buf.length - size >= cb && size <= cb)
       {
           System.arraycopy(buf, savepos, buf, 0, size);
       }
       else
       {
           int newcount = size + cb;
           byte newbuf[] = new byte[Math.max(buf.length << 1, newcount)];
           System.arraycopy(buf, savepos, newbuf, 0, size);
           buf = newbuf;
       }
       if (savepos > 0)
       {
           readpos -= savepos;
           if (markpos > 0)
               markpos -= savepos;
           writepos -= savepos;
       }
   }
   public synchronized int read() throws IOException
   {
       if (readpos >= writepos)
       {
           fill(1);
           if (readpos >= writepos)
               return -1;
       }
       return buf[readpos++] & 0xff;
   }
   /**
    * Read characters into a portion of an array, reading from the underlying
    * stream at most once if necessary.
    */
   public synchronized int read(byte[] b, int off, int len) throws IOException
   {
       int avail = writepos - readpos;
       if (avail < len)
       {
           fill(len - avail);
           avail = writepos - readpos;
           if (avail <= 0) return -1;
       }
       int cnt = (avail < len) ? avail : len;
       System.arraycopy(buf, readpos, b, off, cnt);
       readpos += cnt;
       return cnt;
   }
   public synchronized long skip(long n) throws IOException
   {
       if (n <= 0)
           return 0;
       long avail = writepos - readpos;
       if (avail < n)
       {
           // Fill in buffer to save bytes for reset
           long req = n - avail;
           if (req > Integer.MAX_VALUE)
               req = Integer.MAX_VALUE;
           fill((int)req);
           avail = writepos - readpos;
           if (avail <= 0)
               return 0;
       }
       long skipped = (avail < n) ? avail : n;
       readpos += skipped;
       return skipped;
   }
   public synchronized int available()
   {
       return writepos - readpos;
   }
   public synchronized void mark(int readlimit)
   {
       marklimit = readlimit;
       markpos = readpos;
   }
   public synchronized void reset() throws IOException
   {
       if (markpos < 0)
           throw new IOException("Resetting to invalid mark");
       readpos = markpos;
   }
   public boolean markSupported()
   {
       return true;
   }
   private class InternalOutputStream extends OutputStream
   {
       public synchronized void write(int b) throws IOException
       {
           if (writepos + 1 > buf.length)
           {
               shift(1);
           }
           buf[writepos] = (byte)b;
           writepos += 1;
       }
       public synchronized void write(byte b[], int off, int len)
       {
           if ((off < 0) || (off > b.length) || (len < 0) ||
               ((off + len) > b.length) || ((off + len) < 0))
               throw new IndexOutOfBoundsException();
           else if (len == 0)
               return;
           if (writepos + len > buf.length)
               shift(len);
           System.arraycopy(b, off, buf, writepos, len);
           writepos += len;
       }
   }
}
class SniffedXmlInputStream extends BufferedInputStream
{
    // We don"t sniff more than 192 bytes.
    public static int MAX_SNIFFED_BYTES = 192;
    public SniffedXmlInputStream(InputStream stream) throws IOException
    {
        super(stream);
        // read byte order marks and detect EBCDIC etc
        _encoding = sniffFourBytes();
        if (_encoding != null && _encoding.equals("IBM037"))
        {
            // First four bytes suggest EBCDIC with <?xm at start
            String encoding = sniffForXmlDecl(_encoding);
            if (encoding != null)
                _encoding = encoding;
        }
        if (_encoding == null)
        {
            // Haven"t yet determined encoding: sniff for <?xml encoding="..."?>
            // assuming we can read it as UTF-8.
            _encoding = sniffForXmlDecl("UTF-8");
        }
        if (_encoding == null)
        {
            // The XML spec says these two things:
            // (1) "In the absence of external character encoding information
            // (such as MIME headers), parsed entities which are stored in an
            // encoding other than UTF-8 or UTF-16 must begin with a text
            // declaration (see 4.3.1 The Text Declaration) containing an
            // encoding declaration:"
            // (2) "In the absence of information provided by an external
            // transport protocol (e.g. HTTP or MIME), it is an error
            // for an entity including an encoding declaration to be
            // presented to the XML processor in an encoding other than
            // that named in the declaration, or for an entity which begins
            // with neither a Byte Order Mark nor an encoding declaration
            // to use an encoding other than UTF-8."
            // Since we"re using a sniffed stream, we do not have external
            // character encoding information.
            // Since we"re here, we also don"t have a recognized byte order
            // mark or an explicit encoding declaration that can be read in
            // either ASCII or EBDIC style.
            // Therefore, we must use UTF-8.
            _encoding = "UTF-8";
        }
    }
    private int readAsMuchAsPossible(byte[] buf, int startAt, int len) throws IOException
    {
        int total = 0;
        while (total < len)
        {
            int count = read(buf, startAt + total, len - total);
            if (count < 0)
                break;
            total += count;
        }
        return total;
    }
    private String sniffFourBytes() throws IOException
    {
        mark(4);
        int skip = 0;
        try
        {
            byte[] buf = new byte[4];
            if (readAsMuchAsPossible(buf, 0, 4) < 4)
                return null;
            long result = 0xFF000000 & (buf[0] << 24) | 0x00FF0000 & (buf[1] << 16) | 0x0000FF00 & (buf[2] << 8) | 0x000000FF & buf[3];
            if (result == 0x0000FEFF)
                return "UCS-4";
            else if (result == 0xFFFE0000)
                return "UCS-4";
            else if (result == 0x0000003C)
                return "UCS-4BE";
            else if (result == 0x3C000000)
                return "UCS-4LE";
            else if (result == 0x003C003F)
                return "UTF-16BE";
            else if (result == 0x3C003F00)
                return "UTF-16LE";
            else if (result == 0x3C3F786D)
                return null; // looks like US-ASCII with <?xml: sniff
            else if (result == 0x4C6FA794)
                return "IBM037"; // Sniff for ebdic codepage
            else if ((result & 0xFFFF0000) == 0xFEFF0000)
                return "UTF-16";
            else if ((result & 0xFFFF0000) == 0xFFFE0000)
                return "UTF-16";
            else if ((result & 0xFFFFFF00) == 0xEFBBBF00)
                return "UTF-8";
            else return null;
        }
        finally
        {
            reset();
        }
    }
    // BUGBUG in JDK: Charset.forName is not threadsafe, so we"ll prime it
    // with the common charsets.
    private static Charset dummy1 = Charset.forName("UTF-8");
    private static Charset dummy2 = Charset.forName("UTF-16");
    private static Charset dummy3 = Charset.forName("UTF-16BE");
    private static Charset dummy4 = Charset.forName("UTF-16LE");
    private static Charset dummy5 = Charset.forName("ISO-8859-1");
    private static Charset dummy6 = Charset.forName("US-ASCII");
    private static Charset dummy7 = Charset.forName("Cp1252");

    private String sniffForXmlDecl(String encoding) throws IOException
    {
        mark(MAX_SNIFFED_BYTES);
        try
        {
            byte[] bytebuf = new byte[MAX_SNIFFED_BYTES];
            int bytelimit = readAsMuchAsPossible(bytebuf, 0, MAX_SNIFFED_BYTES);
            // BUGBUG in JDK: Charset.forName is not threadsafe.
            Charset charset = Charset.forName(encoding);
            Reader reader = new InputStreamReader(new ByteArrayInputStream(bytebuf, 0, bytelimit), charset);
            char[] buf = new char[bytelimit];
            int limit = 0;
            while (limit < bytelimit)
            {
                int count = reader.read(buf, limit, bytelimit - limit);
                if (count < 0)
                    break;
                limit += count;
            }
            return extractXmlDeclEncoding(buf, 0, limit);
        }
        finally
        {
            reset();
        }
    }
    private String _encoding;
    public String getXmlEncoding()
    {
        return _encoding;
    }
    /* package */ static String extractXmlDeclEncoding(char[] buf, int offset, int size)
    {
        int limit = offset + size;
        int xmlpi = firstIndexOf("<?xml", buf, offset, limit);
        if (xmlpi >= 0)
        {
            int i = xmlpi + 5;
            ScannedAttribute attr = new ScannedAttribute();
            while (i < limit)
            {
                i = scanAttribute(buf, i, limit, attr);
                if (i < 0)
                    return null;
                if (attr.name.equals("encoding"))
                    return attr.value;
            }
        }
        return null;
    }
    private static int firstIndexOf(String s, char[] buf, int startAt, int limit)
    {
        assert(s.length() > 0);
        char[] lookFor = s.toCharArray();
        char firstchar = lookFor[0];
        searching: for (limit -= lookFor.length; startAt < limit; startAt++)
        {
            if (buf[startAt] == firstchar)
            {
                for (int i = 1; i < lookFor.length; i++)
                {
                    if (buf[startAt + i] != lookFor[i])
                    {
                        continue searching;
                    }
                }
                return startAt;
            }
        }
        return -1;
    }
    private static int nextNonmatchingByte(char[] lookFor, char[] buf, int startAt, int limit)
    {
        searching: for (; startAt < limit; startAt++)
        {
            int thischar = buf[startAt];
            for (int i = 0; i < lookFor.length; i++)
                if (thischar == lookFor[i])
                    continue searching;
            return startAt;
        }
        return -1;
    }
    private static int nextMatchingByte(char[] lookFor, char[] buf, int startAt, int limit)
    {
        searching: for (; startAt < limit; startAt++)
        {
            int thischar = buf[startAt];
            for (int i = 0; i < lookFor.length; i++)
                if (thischar == lookFor[i])
                    return startAt;
        }
        return -1;
    }
    private static int nextMatchingByte(char lookFor, char[] buf, int startAt, int limit)
    {
        searching: for (; startAt < limit; startAt++)
        {
            if (buf[startAt] == lookFor)
                return startAt;
        }
        return -1;
    }
    private static char[] WHITESPACE = new char[] { " ", "\r", "\t", "\n" };
    private static char[] NOTNAME = new char[] { "=", " ", "\r", "\t", "\n", "?", ">", "<", "\"", "\"" };
    private static class ScannedAttribute
    {
        public String name;
        public String value;
    }
    private static int scanAttribute(char[] buf, int startAt, int limit, ScannedAttribute attr)
    {
        int nameStart = nextNonmatchingByte(WHITESPACE, buf, startAt, limit);
        if (nameStart < 0)
            return -1;
        int nameEnd = nextMatchingByte(NOTNAME, buf, nameStart, limit);
        if (nameEnd < 0)
            return -1;
        int equals = nextNonmatchingByte(WHITESPACE, buf, nameEnd, limit);
        if (equals < 0)
            return -1;
        if (buf[equals] != "=")
            return -1;
        int valQuote = nextNonmatchingByte(WHITESPACE, buf, equals + 1, limit);
        if (buf[valQuote] != "\"" && buf[valQuote] != "\"")
            return -1;
        int valEndquote = nextMatchingByte(buf[valQuote], buf, valQuote + 1, limit);
        if (valEndquote < 0)
            return -1;
        attr.name = new String(buf, nameStart, nameEnd - nameStart);
        attr.value = new String(buf, valQuote + 1, valEndquote - valQuote - 1);
        return valEndquote + 1;
    }
}
class SniffedXmlReader extends BufferedReader {
  // We don"t sniff more than 192 bytes.
  public static int MAX_SNIFFED_CHARS = 192;
  public SniffedXmlReader(Reader reader) throws IOException {
    super(reader);
    _encoding = sniffForXmlDecl();
  }
  private int readAsMuchAsPossible(char[] buf, int startAt, int len) throws IOException {
    int total = 0;
    while (total < len) {
      int count = read(buf, startAt + total, len - total);
      if (count < 0)
        break;
      total += count;
    }
    return total;
  }
  // BUGBUG in JDK: Charset.forName is not threadsafe, so we"ll prime it
  // with the common charsets.
  private static Charset dummy1 = Charset.forName("UTF-8");
  private static Charset dummy2 = Charset.forName("UTF-16");
  private static Charset dummy3 = Charset.forName("UTF-16BE");
  private static Charset dummy4 = Charset.forName("UTF-16LE");
  private static Charset dummy5 = Charset.forName("ISO-8859-1");
  private static Charset dummy6 = Charset.forName("US-ASCII");
  private static Charset dummy7 = Charset.forName("Cp1252");
  private String sniffForXmlDecl() throws IOException {
    mark(MAX_SNIFFED_CHARS);
    try {
      char[] buf = new char[MAX_SNIFFED_CHARS];
      int limit = readAsMuchAsPossible(buf, 0, MAX_SNIFFED_CHARS);
      return SniffedXmlInputStream.extractXmlDeclEncoding(buf, 0, limit);
    } finally {
      reset();
    }
  }
  private String _encoding;
  public String getXmlEncoding() {
    return _encoding;
  }
}





Xml Reader To Writer

/*   Copyright 2004 The Apache Software Foundation
 *
 *   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.
 */
// Revised from xmlbeans
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.stream.XMLStreamWriter;
import javax.xml.stream.events.XMLEvent;
public final class XmlReaderToWriter {
  private XmlReaderToWriter() {
  }
  public static void writeAll(XMLStreamReader xmlr, XMLStreamWriter writer)
      throws XMLStreamException {
    while (xmlr.hasNext()) {
      write(xmlr, writer);
      xmlr.next();
    }
    write(xmlr, writer); // write the last element
    writer.flush();
  }
  public static void write(XMLStreamReader xmlr, XMLStreamWriter writer) throws XMLStreamException {
    switch (xmlr.getEventType()) {
    case XMLEvent.START_ELEMENT:
      final String localName = xmlr.getLocalName();
      final String namespaceURI = xmlr.getNamespaceURI();
      if (namespaceURI != null && namespaceURI.length() > 0) {
        final String prefix = xmlr.getPrefix();
        if (prefix != null)
          writer.writeStartElement(prefix, localName, namespaceURI);
        else
          writer.writeStartElement(namespaceURI, localName);
      } else {
        writer.writeStartElement(localName);
      }
      for (int i = 0, len = xmlr.getNamespaceCount(); i < len; i++) {
        writer.writeNamespace(xmlr.getNamespacePrefix(i), xmlr.getNamespaceURI(i));
      }
      for (int i = 0, len = xmlr.getAttributeCount(); i < len; i++) {
        String attUri = xmlr.getAttributeNamespace(i);
        if (attUri != null)
          writer.writeAttribute(attUri, xmlr.getAttributeLocalName(i), xmlr.getAttributeValue(i));
        else
          writer.writeAttribute(xmlr.getAttributeLocalName(i), xmlr.getAttributeValue(i));
      }
      break;
    case XMLEvent.END_ELEMENT:
      writer.writeEndElement();
      break;
    case XMLEvent.SPACE:
    case XMLEvent.CHARACTERS:
      writer.writeCharacters(xmlr.getTextCharacters(), xmlr.getTextStart(), xmlr.getTextLength());
      break;
    case XMLEvent.PROCESSING_INSTRUCTION:
      writer.writeProcessingInstruction(xmlr.getPITarget(), xmlr.getPIData());
      break;
    case XMLEvent.CDATA:
      writer.writeCData(xmlr.getText());
      break;
    case XMLEvent.ruMENT:
      writer.writeComment(xmlr.getText());
      break;
    case XMLEvent.ENTITY_REFERENCE:
      writer.writeEntityRef(xmlr.getLocalName());
      break;
    case XMLEvent.START_DOCUMENT:
      String encoding = xmlr.getCharacterEncodingScheme();
      String version = xmlr.getVersion();
      if (encoding != null && version != null)
        writer.writeStartDocument(encoding, version);
      else if (version != null)
        writer.writeStartDocument(xmlr.getVersion());
      break;
    case XMLEvent.END_DOCUMENT:
      writer.writeEndDocument();
      break;
    case XMLEvent.DTD:
      writer.writeDTD(xmlr.getText());
      break;
    }
  }
}