org.apache.xmlbeans.impl.common.XmlEncodingSniffer Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of commons-xmlbeans Show documentation
The Apache Commons Codec package contains simple encoder and decoders for various formats such as Base64 and Hexadecimal. In addition to these widely used encoders and decoders, the codec package also maintains a collection of phonetic encoding utilities.
The newest version!
/*   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.
 */

package org.apache.xmlbeans.impl.common;

import java.io.Reader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.io.IOException;

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;
    }
}