/*
 * 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.
 */


// Sep 14, 2000:
//  Fixed serializer to report IO exception directly, instead at
//  the end of document processing.
//  Reported by Patrick Higgins <phiggins@transzap.com>
// Aug 21, 2000:
//  Fixed bug in startDocument not calling prepare.
//  Reported by Mikael Staldal <d96-mst-ingen-reklam@d.kth.se>
// Aug 21, 2000:
//  Added ability to omit DOCTYPE declaration.
// Sep 1, 2000:
//   If no output format is provided the serializer now defaults
//   to ISO-8859-1 encoding. Reported by Mikael Staldal
//   <d96-mst@d.kth.se>


package org.apache.xml.serialize;

import java.io.IOException;
import java.io.OutputStream;
import java.io.Writer;
import java.util.Iterator;
import java.util.Locale;
import java.util.Map;

import org.apache.xerces.dom.DOMMessageFormatter;
import org.w3c.dom.Attr;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.xml.sax.AttributeList;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;


Implements an HTML/XHTML serializer supporting both DOM and SAX pretty serializing. HTML/XHTML mode is determined in the constructor. For usage instructions see Serializer. 

If an output stream is used, the encoding is taken from the
output format (defaults to UTF-8). If a writer is
used, make sure the writer uses the same encoding (if applies)
as specified in the output format.
 The serializer supports both DOM and SAX. DOM serializing is done by calling BaseMarkupSerializer.serialize and SAX serializing is done by firing SAX events and using the serializer as a document handler. 
 If an I/O exception occurs while serializing, the serializer will not throw an exception directly, but only throw it at the end of serializing (either DOM or SAX's DocumentHandler.endDocument. 

For elements that are not specified as whitespace preserving,
the serializer will potentially break long text lines at space
boundaries, indent lines, and serialize elements on separate
lines. Line terminators will be regarded as spaces, and
spaces at beginning of line will be stripped.

XHTML is slightly different than HTML:

Element/attribute names are lower case and case matters
Attributes must specify value, even if empty string
Empty elements must have '/' in empty tag
Contents of SCRIPT and STYLE elements serialized as CDATA

Author:
Assaf Arkin
See Also:
Serializer
Deprecated:
This class was deprecated in Xerces 2.6.2. It is
recommended that new applications use JAXP's Transformation API 
for XML (TrAX) for serializing HTML. See the Xerces documentation
for more information.
Version:
$Revision: 704573 $ $Date: 2008-10-14 21:41:22 +0530 (Tue, 14 Oct 2008) $/**
 * Implements an HTML/XHTML serializer supporting both DOM and SAX
 * pretty serializing. HTML/XHTML mode is determined in the
 * constructor.  For usage instructions see {@link Serializer}.
 * <p>
 * If an output stream is used, the encoding is taken from the
 * output format (defaults to <tt>UTF-8</tt>). If a writer is
 * used, make sure the writer uses the same encoding (if applies)
 * as specified in the output format.
 * <p>
 * The serializer supports both DOM and SAX. DOM serializing is done
 * by calling {@link #serialize} and SAX serializing is done by firing
 * SAX events and using the serializer as a document handler.
 * <p>
 * If an I/O exception occurs while serializing, the serializer
 * will not throw an exception directly, but only throw it
 * at the end of serializing (either DOM or SAX's {@link
 * org.xml.sax.DocumentHandler#endDocument}.
 * <p>
 * For elements that are not specified as whitespace preserving,
 * the serializer will potentially break long text lines at space
 * boundaries, indent lines, and serialize elements on separate
 * lines. Line terminators will be regarded as spaces, and
 * spaces at beginning of line will be stripped.
 * <p>
 * XHTML is slightly different than HTML:
 * <ul>
 * <li>Element/attribute names are lower case and case matters
 * <li>Attributes must specify value, even if empty string
 * <li>Empty elements must have '/' in empty tag
 * <li>Contents of SCRIPT and STYLE elements serialized as CDATA
 * </ul>
 *
 * @deprecated This class was deprecated in Xerces 2.6.2. It is
 * recommended that new applications use JAXP's Transformation API 
 * for XML (TrAX) for serializing HTML. See the Xerces documentation
 * for more information.
 * @version $Revision: 704573 $ $Date: 2008-10-14 21:41:22 +0530 (Tue, 14 Oct 2008) $
 * @author <a href="mailto:arkin@intalio.com">Assaf Arkin</a>
 * @see Serializer
 */
public class HTMLSerializer
    extends BaseMarkupSerializer
{


    
True if serializing in XHTML format.
/**
     * True if serializing in XHTML format.
     */
    private boolean _xhtml;


    public static final String XHTMLNamespace = "http://www.w3.org/1999/xhtml";

    // for users to override XHTMLNamespace if need be.
    private String fUserXHTMLNamespace = null;


    
Constructs a new HTML/XHTML serializer depending on the value of
xhtml. The serializer cannot be used without calling BaseMarkupSerializer.setOutputCharStream or BaseMarkupSerializer.setOutputByteStream first. 
Params:
xhtml – True if XHTML serializing/**
     * Constructs a new HTML/XHTML serializer depending on the value of
     * <tt>xhtml</tt>. The serializer cannot be used without calling
     * {@link #setOutputCharStream} or {@link #setOutputByteStream} first.
     *
     * @param xhtml True if XHTML serializing
     */
    protected HTMLSerializer( boolean xhtml, OutputFormat format )
    {
        super( format );
        _xhtml = xhtml;
    }


    
Constructs a new serializer. The serializer cannot be used without calling BaseMarkupSerializer.setOutputCharStream or BaseMarkupSerializer.setOutputByteStream first. /**
     * Constructs a new serializer. The serializer cannot be used without
     * calling {@link #setOutputCharStream} or {@link #setOutputByteStream}
     * first.
     */
    public HTMLSerializer()
    {
        this( false, new OutputFormat( Method.HTML, "ISO-8859-1", false ) );
    }


    
Constructs a new serializer. The serializer cannot be used without calling BaseMarkupSerializer.setOutputCharStream or BaseMarkupSerializer.setOutputByteStream first. /**
     * Constructs a new serializer. The serializer cannot be used without
     * calling {@link #setOutputCharStream} or {@link #setOutputByteStream}
     * first.
     */
    public HTMLSerializer( OutputFormat format )
    {
        this( false, format != null ? format : new OutputFormat( Method.HTML, "ISO-8859-1", false ) );
    }



    
Constructs a new serializer that writes to the specified writer
using the specified output format. If format is null,
will use a default output format.
Params:
writer – The writer to use
format – The output format to use, null for the default/**
     * Constructs a new serializer that writes to the specified writer
     * using the specified output format. If <tt>format</tt> is null,
     * will use a default output format.
     *
     * @param writer The writer to use
     * @param format The output format to use, null for the default
     */
    public HTMLSerializer( Writer writer, OutputFormat format )
    {
        this( false, format != null ? format : new OutputFormat( Method.HTML, "ISO-8859-1", false ) );
        setOutputCharStream( writer );
    }


    
Constructs a new serializer that writes to the specified output
stream using the specified output format. If format
is null, will use a default output format.
Params:
output – The output stream to use
format – The output format to use, null for the default/**
     * Constructs a new serializer that writes to the specified output
     * stream using the specified output format. If <tt>format</tt>
     * is null, will use a default output format.
     *
     * @param output The output stream to use
     * @param format The output format to use, null for the default
     */
    public HTMLSerializer( OutputStream output, OutputFormat format )
    {
        this( false, format != null ? format : new OutputFormat( Method.HTML, "ISO-8859-1", false ) );
        setOutputByteStream( output );
    }


    public void setOutputFormat( OutputFormat format )
    {
        super.setOutputFormat( format != null ? format : new OutputFormat( Method.HTML, "ISO-8859-1", false ) );
    }

    // Set  value for alternate XHTML namespace.
    public void setXHTMLNamespace(String newNamespace) {
        fUserXHTMLNamespace = newNamespace;
    } // setXHTMLNamespace(String)

    //-----------------------------------------//
    // SAX content handler serializing methods //
    //-----------------------------------------//


    public void startElement( String namespaceURI, String localName,
                              String rawName, Attributes attrs )
        throws SAXException
    {
        int          i;
        boolean      preserveSpace;
        ElementState state;
        String       name;
        String       value;
        String       htmlName;
        boolean      addNSAttr = false;

        try {
            if ( _printer == null )
            	throw new IllegalStateException( 
				    DOMMessageFormatter.formatMessage(
				    DOMMessageFormatter.SERIALIZER_DOMAIN,
                    "NoWriterSupplied", null));

            state = getElementState();
            if ( isDocumentState() ) {
                // If this is the root element handle it differently.
                // If the first root element in the document, serialize
                // the document's DOCTYPE. Space preserving defaults
                // to that of the output format.
                if ( ! _started )
                    startDocument( (localName == null || localName.length() == 0) 
                        ? rawName : localName );
            } else {
                // For any other element, if first in parent, then
                // close parent's opening tag and use the parnet's
                // space preserving.
                if ( state.empty )
                    _printer.printText( '>' );
                // Indent this element on a new line if the first
                // content of the parent element or immediately
                // following an element.
                if ( _indenting && ! state.preserveSpace &&
                     ( state.empty || state.afterElement ) )
                    _printer.breakLine();
            }
            preserveSpace = state.preserveSpace;

            // Do not change the current element state yet.
            // This only happens in endElement().
            
            // As per SAX2, the namespace URI is an empty string if the element has no
            // namespace URI, or namespaces is turned off. The check against null protects
            // against broken SAX implementations, so I've left it there. - mrglavas
            boolean hasNamespaceURI = (namespaceURI != null && namespaceURI.length() != 0);

            // SAX2: rawName (QName) could be empty string if 
            // namespace-prefixes property is false.
            if ( rawName == null || rawName.length() == 0) {
                rawName = localName;
                if ( hasNamespaceURI ) {
                    String prefix;
                    prefix = getPrefix( namespaceURI );
                    if ( prefix != null && prefix.length() != 0 )
                        rawName = prefix + ":" + localName;
                }
                addNSAttr = true;
            }
            if ( !hasNamespaceURI )
                htmlName = rawName;
            else {
                if ( namespaceURI.equals( XHTMLNamespace ) ||
                        (fUserXHTMLNamespace != null && fUserXHTMLNamespace.equals(namespaceURI)) )
                    htmlName = localName;
                else
                    htmlName = null;
            }

            // XHTML: element names are lower case, DOM will be different
            _printer.printText( '<' );
            if ( _xhtml )
                _printer.printText( rawName.toLowerCase(Locale.ENGLISH) );
            else
                _printer.printText( rawName );
            _printer.indent();

            // For each attribute serialize it's name and value as one part,
            // separated with a space so the element can be broken on
            // multiple lines.
            if ( attrs != null ) {
                for ( i = 0 ; i < attrs.getLength() ; ++i ) {
                    _printer.printSpace();
                    name = attrs.getQName( i ).toLowerCase(Locale.ENGLISH);
                    value = attrs.getValue( i );
                    if ( _xhtml || hasNamespaceURI ) {
                        // XHTML: print empty string for null values.
                        if ( value == null ) {
                            _printer.printText( name );
                            _printer.printText( "=\"\"" );
                        } else {
                            _printer.printText( name );
                            _printer.printText( "=\"" );
                            printEscaped( value );
                            _printer.printText( '"' );
                        }
                    } else {
                        // HTML: Empty values print as attribute name, no value.
                        // HTML: URI attributes will print unescaped
                        if ( value == null ) {
                            value = "";
                        }
                        if ( !_format.getPreserveEmptyAttributes() && value.length() == 0 )
                            _printer.printText( name );
                        else if ( HTMLdtd.isURI( rawName, name ) ) {
                            _printer.printText( name );
                            _printer.printText( "=\"" );
                            _printer.printText( escapeURI( value ) );
                            _printer.printText( '"' );
                        } else if ( HTMLdtd.isBoolean( rawName, name ) )
                            _printer.printText( name );
                        else {
                            _printer.printText( name );
                            _printer.printText( "=\"" );
                            printEscaped( value );
                            _printer.printText( '"' );
                        }
                    }
                }
            }
            if ( htmlName != null && HTMLdtd.isPreserveSpace( htmlName ) )
                preserveSpace = true;

            if ( addNSAttr ) {
                Iterator entries = _prefixes.entrySet().iterator();
                while (entries.hasNext()) {
                    _printer.printSpace();
                    Map.Entry entry = (Map.Entry) entries.next();
                    value = (String) entry.getKey();
                    name = (String) entry.getValue();
                    if ( name.length() == 0 ) {
                        _printer.printText( "xmlns=\"" );
                        printEscaped( value );
                        _printer.printText( '"' );
                    } 
                    else {
                        _printer.printText( "xmlns:" );
                        _printer.printText( name );
                        _printer.printText( "=\"" );
                        printEscaped( value );
                        _printer.printText( '"' );
                    }
                }
            }

            // Now it's time to enter a new element state
            // with the tag name and space preserving.
            // We still do not change the curent element state.
            state = enterElementState( namespaceURI, localName, rawName, preserveSpace );

            // Prevents line breaks inside A/TD

            if ( htmlName != null && ( htmlName.equalsIgnoreCase( "A" ) ||
                                       htmlName.equalsIgnoreCase( "TD" ) ) ) {
                state.empty = false;
                _printer.printText( '>' );
            }

            // Handle SCRIPT and STYLE specifically by changing the
            // state of the current element to CDATA (XHTML) or
            // unescaped (HTML).
            if ( htmlName != null && ( rawName.equalsIgnoreCase( "SCRIPT" ) ||
                                       rawName.equalsIgnoreCase( "STYLE" ) ) ) {
                if ( _xhtml ) {
                    // XHTML: Print contents as CDATA section
                    state.doCData = true;
                } else {
                    // HTML: Print contents unescaped
                    state.unescaped = true;
                }
            }
        } catch ( IOException except ) {
            throw new SAXException( except );
        }
    }


    public void endElement( String namespaceURI, String localName,
                            String rawName )
        throws SAXException
    {
        try {
            endElementIO( namespaceURI, localName, rawName );
        } catch ( IOException except ) {
            throw new SAXException( except );
        }
    }


    public void endElementIO( String namespaceURI, String localName,
                              String rawName )
        throws IOException
    {
        ElementState state;
        String       htmlName;

        // Works much like content() with additions for closing
        // an element. Note the different checks for the closed
        // element's state and the parent element's state.
        _printer.unindent();
        state = getElementState();

        if ( state.namespaceURI == null || state.namespaceURI.length() == 0 )
            htmlName = state.rawName;
        else {
            if ( state.namespaceURI.equals( XHTMLNamespace ) ||
                        (fUserXHTMLNamespace != null && fUserXHTMLNamespace.equals(state.namespaceURI)) )
                htmlName = state.localName;
            else
                htmlName = null;
        }

        if ( _xhtml) {
            if ( state.empty ) {
                _printer.printText( " />" );
            } else {
                // Must leave CData section first
                if ( state.inCData )
                    _printer.printText( "]]>" );
                // XHTML: element names are lower case, DOM will be different
                _printer.printText( "</" );
                _printer.printText( state.rawName.toLowerCase(Locale.ENGLISH) );
                _printer.printText( '>' );
            }
        } else {
            if ( state.empty )
                _printer.printText( '>' );
            // This element is not empty and that last content was
            // another element, so print a line break before that
            // last element and this element's closing tag.
            // [keith] Provided this is not an anchor.
            // HTML: some elements do not print closing tag (e.g. LI)
            if ( htmlName == null || ! HTMLdtd.isOnlyOpening( htmlName ) ) {
                if ( _indenting && ! state.preserveSpace && state.afterElement )
                    _printer.breakLine();
                // Must leave CData section first (Illegal in HTML, but still)
                if ( state.inCData )
                    _printer.printText( "]]>" );
                _printer.printText( "</" );
                _printer.printText( state.rawName );
                _printer.printText( '>' );
            }
        }
        // Leave the element state and update that of the parent
        // (if we're not root) to not empty and after element.
        state = leaveElementState();
        // Temporary hack to prevent line breaks inside A/TD
        if ( htmlName == null || ( ! htmlName.equalsIgnoreCase( "A" ) &&
                                   ! htmlName.equalsIgnoreCase( "TD" ) ) )

            state.afterElement = true;
        state.empty = false;
        if ( isDocumentState() )
            _printer.flush();
    }


    //------------------------------------------//
    // SAX document handler serializing methods //
    //------------------------------------------//


    public void characters( char[] chars, int start, int length )
        throws SAXException
    {
        ElementState state;

        try {
            // HTML: no CDATA section
            state = content();
            state.doCData = false;
            super.characters( chars, start, length );
        } catch ( IOException except ) {
            throw new SAXException( except );
        }
    }


    public void startElement( String tagName, AttributeList attrs )
        throws SAXException
    {
        int          i;
        boolean      preserveSpace;
        ElementState state;
        String       name;
        String       value;

        try {
            if ( _printer == null )
                throw new IllegalStateException( 
				    DOMMessageFormatter.formatMessage(
				    DOMMessageFormatter.SERIALIZER_DOMAIN,
                    "NoWriterSupplied", null));


            state = getElementState();
            if ( isDocumentState() ) {
                // If this is the root element handle it differently.
                // If the first root element in the document, serialize
                // the document's DOCTYPE. Space preserving defaults
                // to that of the output format.
                if ( ! _started )
                    startDocument( tagName );
            } else {
                // For any other element, if first in parent, then
                // close parent's opening tag and use the parnet's
                // space preserving.
                if ( state.empty )
                    _printer.printText( '>' );
                // Indent this element on a new line if the first
                // content of the parent element or immediately
                // following an element.
                if ( _indenting && ! state.preserveSpace &&
                     ( state.empty || state.afterElement ) )
                    _printer.breakLine();
            }
            preserveSpace = state.preserveSpace;

            // Do not change the current element state yet.
            // This only happens in endElement().

            // XHTML: element names are lower case, DOM will be different
            _printer.printText( '<' );
            if ( _xhtml )
                _printer.printText( tagName.toLowerCase(Locale.ENGLISH) );
            else
                _printer.printText( tagName );
            _printer.indent();

            // For each attribute serialize it's name and value as one part,
            // separated with a space so the element can be broken on
            // multiple lines.
            if ( attrs != null ) {
                for ( i = 0 ; i < attrs.getLength() ; ++i ) {
                    _printer.printSpace();
                    name = attrs.getName( i ).toLowerCase(Locale.ENGLISH);
                    value = attrs.getValue( i );
                    if ( _xhtml ) {
                        // XHTML: print empty string for null values.
                        if ( value == null ) {
                            _printer.printText( name );
                            _printer.printText( "=\"\"" );
                        } else {
                            _printer.printText( name );
                            _printer.printText( "=\"" );
                            printEscaped( value );
                            _printer.printText( '"' );
                        }
                    } else {
                        // HTML: Empty values print as attribute name, no value.
                        // HTML: URI attributes will print unescaped
                        if ( value == null ) {
                            value = "";
                        }
                        if ( !_format.getPreserveEmptyAttributes() && value.length() == 0 )
                            _printer.printText( name );
                        else if ( HTMLdtd.isURI( tagName, name ) ) {
                            _printer.printText( name );
                            _printer.printText( "=\"" );
                            _printer.printText( escapeURI( value ) );
                            _printer.printText( '"' );
                        } else if ( HTMLdtd.isBoolean( tagName, name ) )
                            _printer.printText( name );
                        else {
                            _printer.printText( name );
                            _printer.printText( "=\"" );
                            printEscaped( value );
                            _printer.printText( '"' );
                        }
                    }
                }
            }
            if ( HTMLdtd.isPreserveSpace( tagName ) )
                preserveSpace = true;

            // Now it's time to enter a new element state
            // with the tag name and space preserving.
            // We still do not change the curent element state.
            state = enterElementState( null, null, tagName, preserveSpace );

            // Prevents line breaks inside A/TD
            if ( tagName.equalsIgnoreCase( "A" ) || tagName.equalsIgnoreCase( "TD" ) ) {
                state.empty = false;
                _printer.printText( '>' );
            }

            // Handle SCRIPT and STYLE specifically by changing the
            // state of the current element to CDATA (XHTML) or
            // unescaped (HTML).
            if ( tagName.equalsIgnoreCase( "SCRIPT" ) ||
                 tagName.equalsIgnoreCase( "STYLE" ) ) {
                if ( _xhtml ) {
                    // XHTML: Print contents as CDATA section
                    state.doCData = true;
                } else {
                    // HTML: Print contents unescaped
                    state.unescaped = true;
                }
            }
        } catch ( IOException except ) {
            throw new SAXException( except );
        }
    }


    public void endElement( String tagName )
        throws SAXException
    {
        endElement( null, null, tagName );
    }


    //------------------------------------------//
    // Generic node serializing methods methods //
    //------------------------------------------//


    
Called to serialize the document's DOCTYPE by the root element.
The document type declaration must name the root element,
but the root element is only known when that element is serialized,
and not at the start of the document.
 This method will check if it has not been called before (BaseMarkupSerializer._started), will serialize the document type declaration, and will serialize all pre-root comments and PIs that were accumulated in the document (see BaseMarkupSerializer.serializePreRoot). Pre-root will be serialized even if this is not the first root element of the document. /**
     * Called to serialize the document's DOCTYPE by the root element.
     * The document type declaration must name the root element,
     * but the root element is only known when that element is serialized,
     * and not at the start of the document.
     * <p>
     * This method will check if it has not been called before ({@link #_started}),
     * will serialize the document type declaration, and will serialize all
     * pre-root comments and PIs that were accumulated in the document
     * (see {@link #serializePreRoot}). Pre-root will be serialized even if
     * this is not the first root element of the document.
     */
    protected void startDocument( String rootTagName )
        throws IOException
    {
        // Not supported in HTML/XHTML, but we still have to switch
        // out of DTD mode.
        _printer.leaveDTD();
        if ( ! _started ) {
            // If the public and system identifiers were not specified
            // in the output format, use the appropriate ones for HTML
            // or XHTML.
            if ( _docTypePublicId == null && _docTypeSystemId == null ) {
                if ( _xhtml ) {
                    _docTypePublicId = HTMLdtd.XHTMLPublicId;
                    _docTypeSystemId = HTMLdtd.XHTMLSystemId;
                } else {
                    _docTypePublicId = HTMLdtd.HTMLPublicId;
                    _docTypeSystemId = HTMLdtd.HTMLSystemId;
                }
            }

            if ( ! _format.getOmitDocumentType() ) {
                // XHTML: If public identifier and system identifier
                //  specified, print them, else print just system identifier
                // HTML: If public identifier specified, print it with
                //  system identifier, if specified.
                // XHTML requires that all element names are lower case, so the
                // root on the DOCTYPE must be 'html'. - mrglavas
                if ( _docTypePublicId != null && ( ! _xhtml || _docTypeSystemId != null )  ) {
                    if (_xhtml) {
                        _printer.printText( "<!DOCTYPE html PUBLIC " );
                    }
                    else {
                        _printer.printText( "<!DOCTYPE HTML PUBLIC " );
                    }
                    printDoctypeURL( _docTypePublicId );
                    if ( _docTypeSystemId != null ) {
                        if ( _indenting ) {
                            _printer.breakLine();
                            _printer.printText( "                      " );
                        } else
                        _printer.printText( ' ' );
                        printDoctypeURL( _docTypeSystemId );
                    }
                    _printer.printText( '>' );
                    _printer.breakLine();
                } else if ( _docTypeSystemId != null ) {
                    if (_xhtml) {
                        _printer.printText( "<!DOCTYPE html SYSTEM " );
                    }
                    else {
                        _printer.printText( "<!DOCTYPE HTML SYSTEM " );
                    }
                    printDoctypeURL( _docTypeSystemId );
                    _printer.printText( '>' );
                    _printer.breakLine();
                }
            }
        }

        _started = true;
        // Always serialize these, even if not te first root element.
        serializePreRoot();
    }


    
Called to serialize a DOM element. Equivalent to calling startElement, endElement and serializing everything inbetween, but better optimized. /**
     * Called to serialize a DOM element. Equivalent to calling {@link
     * #startElement}, {@link #endElement} and serializing everything
     * inbetween, but better optimized.
     */
    protected void serializeElement( Element elem )
        throws IOException
    {
        Attr         attr;
        NamedNodeMap attrMap;
        int          i;
        Node         child;
        ElementState state;
        boolean      preserveSpace;
        String       name;
        String       value;
        String       tagName;

        tagName = elem.getTagName();
        state = getElementState();
        if ( isDocumentState() ) {
            // If this is the root element handle it differently.
            // If the first root element in the document, serialize
            // the document's DOCTYPE. Space preserving defaults
            // to that of the output format.
            if ( ! _started )
                startDocument( tagName );
        } else {
            // For any other element, if first in parent, then
            // close parent's opening tag and use the parnet's
            // space preserving.
            if ( state.empty )
                _printer.printText( '>' );
            // Indent this element on a new line if the first
            // content of the parent element or immediately
            // following an element.
            if ( _indenting && ! state.preserveSpace &&
                 ( state.empty || state.afterElement ) )
                _printer.breakLine();
        }
        preserveSpace = state.preserveSpace;

        // Do not change the current element state yet.
        // This only happens in endElement().

        // XHTML: element names are lower case, DOM will be different
        _printer.printText( '<' );
        if ( _xhtml )
            _printer.printText( tagName.toLowerCase(Locale.ENGLISH) );
        else
            _printer.printText( tagName );
        _printer.indent();

        // Lookup the element's attribute, but only print specified
        // attributes. (Unspecified attributes are derived from the DTD.
        // For each attribute print it's name and value as one part,
        // separated with a space so the element can be broken on
        // multiple lines.
        attrMap = elem.getAttributes();
        if ( attrMap != null ) {
            for ( i = 0 ; i < attrMap.getLength() ; ++i ) {
                attr = (Attr) attrMap.item( i );
                name = attr.getName().toLowerCase(Locale.ENGLISH);
                value = attr.getValue();
                if ( attr.getSpecified() ) {
                    _printer.printSpace();
                    if ( _xhtml ) {
                        // XHTML: print empty string for null values.
                        if ( value == null ) {
                            _printer.printText( name );
                            _printer.printText( "=\"\"" );
                        } else {
                            _printer.printText( name );
                            _printer.printText( "=\"" );
                            printEscaped( value );
                            _printer.printText( '"' );
                        }
                    } else {
                        // HTML: Empty values print as attribute name, no value.
                        // HTML: URI attributes will print unescaped
                        if ( value == null ) {
                            value = "";
                        }
                        if ( !_format.getPreserveEmptyAttributes() && value.length() == 0 )
                            _printer.printText( name );
                        else if ( HTMLdtd.isURI( tagName, name ) ) {
                            _printer.printText( name );
                            _printer.printText( "=\"" );
                            _printer.printText( escapeURI( value ) );
                            _printer.printText( '"' );
                        } else if ( HTMLdtd.isBoolean( tagName, name ) )
                            _printer.printText( name );
                        else {
                            _printer.printText( name );
                            _printer.printText( "=\"" );
                            printEscaped( value );
                            _printer.printText( '"' );
                        }
                    }
                }
            }
        }
        if ( HTMLdtd.isPreserveSpace( tagName ) )
            preserveSpace = true;

        // If element has children, or if element is not an empty tag,
        // serialize an opening tag.
        if ( elem.hasChildNodes() || ! HTMLdtd.isEmptyTag( tagName ) ) {
            // Enter an element state, and serialize the children
            // one by one. Finally, end the element.
            state = enterElementState( null, null, tagName, preserveSpace );

            // Prevents line breaks inside A/TD
            if ( tagName.equalsIgnoreCase( "A" ) || tagName.equalsIgnoreCase( "TD" ) ) {
                state.empty = false;
                _printer.printText( '>' );
            }

            // Handle SCRIPT and STYLE specifically by changing the
            // state of the current element to CDATA (XHTML) or
            // unescaped (HTML).
            if ( tagName.equalsIgnoreCase( "SCRIPT" ) ||
                 tagName.equalsIgnoreCase( "STYLE" ) ) {
                if ( _xhtml ) {
                    // XHTML: Print contents as CDATA section
                    state.doCData = true;
                } else {
                    // HTML: Print contents unescaped
                    state.unescaped = true;
                }
            }
            child = elem.getFirstChild();
            while ( child != null ) {
                serializeNode( child );
                child = child.getNextSibling();
            }
            endElementIO( null, null, tagName );
        } else {
            _printer.unindent();
            // XHTML: Close empty tag with ' />' so it's XML and HTML compatible.
            // HTML: Empty tags are defined as such in DTD no in document.
            if ( _xhtml )
                _printer.printText( " />" );
            else
                _printer.printText( '>' );
            // After element but parent element is no longer empty.
            state.afterElement = true;
            state.empty = false;
            if ( isDocumentState() )
                _printer.flush();
        }
    }



    protected void characters( String text )
        throws IOException
    {
        // HTML: no CDATA section
        content();
        super.characters( text );
    }


    protected String getEntityRef( int ch )
    {
        return HTMLdtd.fromChar( ch );
    }


    protected String escapeURI( String uri )
    {
        int index;

        // XXX  Apparently Netscape doesn't like if we escape the URI
        //      using %nn, so we leave it as is, just remove any quotes.
        index = uri.indexOf( "\"" );
        if ( index >= 0 ) {
            return uri.substring( 0, index );
        }
        return uri;
    }

}