/*
 * 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.
 */

package org.apache.xml.serialize;

import java.io.IOException;
import java.io.OutputStream;
import java.io.StringWriter;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.lang.reflect.Method;
import java.util.ArrayList;

import org.apache.xerces.dom.CoreDocumentImpl;
import org.apache.xerces.dom.DOMErrorImpl;
import org.apache.xerces.dom.DOMLocatorImpl;
import org.apache.xerces.dom.DOMMessageFormatter;
import org.apache.xerces.dom.DOMNormalizer;
import org.apache.xerces.dom.DOMStringListImpl;
import org.apache.xerces.impl.Constants;
import org.apache.xerces.impl.XMLEntityManager;
import org.apache.xerces.util.DOMUtil;
import org.apache.xerces.util.NamespaceSupport;
import org.apache.xerces.util.SymbolTable;
import org.apache.xerces.util.XML11Char;
import org.apache.xerces.util.XMLChar;
import org.w3c.dom.Attr;
import org.w3c.dom.Comment;
import org.w3c.dom.DOMConfiguration;
import org.w3c.dom.DOMError;
import org.w3c.dom.DOMErrorHandler;
import org.w3c.dom.DOMException;
import org.w3c.dom.DOMStringList;
import org.w3c.dom.Document;
import org.w3c.dom.DocumentFragment;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.ProcessingInstruction;
import org.w3c.dom.ls.LSException;
import org.w3c.dom.ls.LSOutput;
import org.w3c.dom.ls.LSSerializer;
import org.w3c.dom.ls.LSSerializerFilter;

EXPERIMENTAL: Implemenatation of DOM Level 3 org.w3c.ls.LSSerializer  by delegating serialization
calls to XMLSerializer.
LSSerializer provides an API for serializing (writing) a DOM document out in an
XML document. The XML data is written to an output stream.
During serialization of XML data, namespace fixup is done when possible as
defined in DOM Level 3 Core, Appendix B.
Author:
Elena Litani, IBM, Gopal Sharma, Sun Microsystems, Arun Yadav, Sun Microsystems
Version:
$Id: DOMSerializerImpl.java 944789 2010-05-16 10:06:57Z mukulg $
Deprecated:
Replaced by org.apache.xml.serializer.dom3.LSSerializerImpl in Xerces 2.9.0./**
 * EXPERIMENTAL: Implemenatation of DOM Level 3 org.w3c.ls.LSSerializer  by delegating serialization
 * calls to <CODE>XMLSerializer</CODE>.
 * LSSerializer provides an API for serializing (writing) a DOM document out in an
 * XML document. The XML data is written to an output stream.
 * During serialization of XML data, namespace fixup is done when possible as
 * defined in DOM Level 3 Core, Appendix B.
 *
 * @author Elena Litani, IBM
 * @author Gopal Sharma, Sun Microsystems
 * @author Arun Yadav, Sun Microsystems
 * @version $Id: DOMSerializerImpl.java 944789 2010-05-16 10:06:57Z mukulg $
 * 
 * @deprecated Replaced by org.apache.xml.serializer.dom3.LSSerializerImpl in Xerces 2.9.0.
 */
public class DOMSerializerImpl implements LSSerializer, DOMConfiguration {

    // TODO: When DOM Level 3 goes to REC replace method calls using
    // reflection for: getXmlEncoding, getInputEncoding and getXmlEncoding
    // with regular static calls on the Document object.
	
    // data
    // serializer
    private XMLSerializer serializer;

    // XML 1.1 serializer
    private XML11Serializer xml11Serializer;
    
    //Recognized parameters
    private DOMStringList fRecognizedParameters;
    
    
REVISIT: Currently we handle 3 different configurations, would be nice just have one configuration
that has different recognized parameters depending if it is used in Core/LS. 
/** REVISIT: Currently we handle 3 different configurations, would be nice just have one configuration
     * that has different recognized parameters depending if it is used in Core/LS. 
     */
    protected short features = 0;

    protected final static short NAMESPACES          = 0x1<<0;
    protected final static short WELLFORMED          = 0x1<<1;
    protected final static short ENTITIES            = 0x1<<2;
    protected final static short CDATA               = 0x1<<3;
    protected final static short SPLITCDATA          = 0x1<<4;
    protected final static short COMMENTS            = 0x1<<5;
    protected final static short DISCARDDEFAULT      = 0x1<<6;
    protected final static short INFOSET             = 0x1<<7;
    protected final static short XMLDECL             = 0x1<<8;
    protected final static short NSDECL              = 0x1<<9;
    protected final static short DOM_ELEMENT_CONTENT_WHITESPACE = 0x1<<10;
    protected final static short PRETTY_PRINT        = 0x1<<11;
    
    // well-formness checking
    private DOMErrorHandler fErrorHandler = null;    
    private final DOMErrorImpl fError = new DOMErrorImpl();
    private final DOMLocatorImpl fLocator = new DOMLocatorImpl();

    
Constructs a new LSSerializer.
The constructor turns on the namespace support in XMLSerializer and
initializes the following fields: fNSBinder, fLocalNSBinder, fSymbolTable,
fEmptySymbol, fXmlSymbol, fXmlnsSymbol, fNamespaceCounter, fFeatures.
/**
     * Constructs a new LSSerializer.
     * The constructor turns on the namespace support in <code>XMLSerializer</code> and
     * initializes the following fields: fNSBinder, fLocalNSBinder, fSymbolTable,
     * fEmptySymbol, fXmlSymbol, fXmlnsSymbol, fNamespaceCounter, fFeatures.
     */
    public DOMSerializerImpl() {
        // set default features
        features |= NAMESPACES;
        features |= ENTITIES;
        features |= COMMENTS;
        features |= CDATA;
        features |= SPLITCDATA;
        features |= WELLFORMED;
        features |= NSDECL;
        features |= DOM_ELEMENT_CONTENT_WHITESPACE;
        features |= DISCARDDEFAULT;
        features |= XMLDECL;
             
        serializer = new XMLSerializer();
        initSerializer(serializer);
    }



    //
    // LSSerializer methods
    //

    public DOMConfiguration getDomConfig(){
        return this;
    }

    
DOM L3-EXPERIMENTAL:
Setter for boolean and object parameters
/** DOM L3-EXPERIMENTAL:
     * Setter for boolean and object parameters
     */
    public void setParameter(String name, Object value) throws DOMException {
        if (value instanceof Boolean) {
            boolean state = ((Boolean) value).booleanValue();
            if (name.equalsIgnoreCase(Constants.DOM_INFOSET)){
                if (state){
                    features &= ~ENTITIES;
                    features &= ~CDATA;
                    features |= NAMESPACES;
                    features |= NSDECL;
                    features |= WELLFORMED;
                    features |= COMMENTS;                 
                }
                // false does not have any effect
            } else if (name.equalsIgnoreCase(Constants.DOM_XMLDECL)) {
                features =
                    (short) (state ? features | XMLDECL : features & ~XMLDECL);                
            } else if (name.equalsIgnoreCase(Constants.DOM_NAMESPACES)) {
                features =
                    (short) (state
                        ? features | NAMESPACES
                        : features & ~NAMESPACES);
                serializer.fNamespaces = state;
            } else if (name.equalsIgnoreCase(Constants.DOM_SPLIT_CDATA)) {
                features =
                    (short) (state
                        ? features | SPLITCDATA
                        : features & ~SPLITCDATA);
            } else if (name.equalsIgnoreCase(Constants.DOM_DISCARD_DEFAULT_CONTENT)) {
                features =
                    (short) (state
                        ? features | DISCARDDEFAULT
                        : features & ~DISCARDDEFAULT);
            } else if (name.equalsIgnoreCase(Constants.DOM_WELLFORMED)) {
                features =
                    (short) (state
                        ? features | WELLFORMED
                        : features & ~WELLFORMED);
            } else if (name.equalsIgnoreCase(Constants.DOM_ENTITIES)){
                features =
                    (short) (state
                        ? features | ENTITIES
                        : features & ~ENTITIES);
            }
            else if (name.equalsIgnoreCase(Constants.DOM_CDATA_SECTIONS)){
                features =
                    (short) (state
                        ? features | CDATA
                        : features & ~CDATA);
                        }
            else if (name.equalsIgnoreCase(Constants.DOM_COMMENTS)){
                features =
                     (short) (state
                         ? features | COMMENTS
                         : features & ~COMMENTS);
            } else if (name.equalsIgnoreCase(Constants.DOM_FORMAT_PRETTY_PRINT)) {
                features =
                     (short) (state
                         ? features | PRETTY_PRINT
                         : features & ~PRETTY_PRINT);
            }
                else if (name.equalsIgnoreCase(Constants.DOM_CANONICAL_FORM)
                    || name.equalsIgnoreCase(Constants.DOM_VALIDATE_IF_SCHEMA)
                    || name.equalsIgnoreCase(Constants.DOM_VALIDATE)
                    || name.equalsIgnoreCase(Constants.DOM_CHECK_CHAR_NORMALIZATION)
                    || name.equalsIgnoreCase(Constants.DOM_DATATYPE_NORMALIZATION)
                    || name.equalsIgnoreCase(Constants.DOM_NORMALIZE_CHARACTERS)) {
                // true is not supported
                if (state) {
                    String msg =
                        DOMMessageFormatter.formatMessage(
                            DOMMessageFormatter.DOM_DOMAIN,
                            "FEATURE_NOT_SUPPORTED",
                            new Object[] { name });
                    throw new DOMException(DOMException.NOT_SUPPORTED_ERR, msg);
                }
            }else if (
			name.equalsIgnoreCase(Constants.DOM_NAMESPACE_DECLARATIONS)) {
				//namespace-declaration has effect only if namespaces is true
				features =
					(short) (state
						? features | NSDECL
						: features & ~NSDECL);
				serializer.fNamespacePrefixes = state;							
            } else if (name.equalsIgnoreCase(Constants.DOM_ELEMENT_CONTENT_WHITESPACE)
                    || name.equalsIgnoreCase(Constants.DOM_IGNORE_UNKNOWN_CHARACTER_DENORMALIZATIONS)) {
                // false is not supported
                if (!state) {
                    String msg =
                        DOMMessageFormatter.formatMessage(
                            DOMMessageFormatter.DOM_DOMAIN,
                            "FEATURE_NOT_SUPPORTED",
                            new Object[] { name });
                    throw new DOMException(DOMException.NOT_SUPPORTED_ERR, msg);
                }
            } else {
                String msg =
                    DOMMessageFormatter.formatMessage(
                        DOMMessageFormatter.DOM_DOMAIN,
                        "FEATURE_NOT_FOUND",
                        new Object[] { name });
                throw new DOMException(DOMException.NOT_SUPPORTED_ERR, msg);
            }
        } else if (name.equalsIgnoreCase(Constants.DOM_ERROR_HANDLER)) {
            if (value == null || value instanceof DOMErrorHandler) {
                fErrorHandler = (DOMErrorHandler)value;
            } else {
                String msg =
                    DOMMessageFormatter.formatMessage(
                        DOMMessageFormatter.DOM_DOMAIN,
                        "TYPE_MISMATCH_ERR",
                        new Object[] { name });
                throw new DOMException(DOMException.TYPE_MISMATCH_ERR, msg);
            }
        } else if (
            name.equalsIgnoreCase(Constants.DOM_RESOURCE_RESOLVER)
                || name.equalsIgnoreCase(Constants.DOM_SCHEMA_LOCATION)
                || name.equalsIgnoreCase(Constants.DOM_SCHEMA_TYPE)
                && value != null) {
            String msg =
                DOMMessageFormatter.formatMessage(
                    DOMMessageFormatter.DOM_DOMAIN,
                    "FEATURE_NOT_SUPPORTED",
                    new Object[] { name });
            throw new DOMException(DOMException.NOT_SUPPORTED_ERR, msg);
        } else {
            String msg =
                DOMMessageFormatter.formatMessage(
                    DOMMessageFormatter.DOM_DOMAIN,
                    "FEATURE_NOT_FOUND",
                    new Object[] { name });
            throw new DOMException(DOMException.NOT_FOUND_ERR, msg);
        }
    }

    
DOM L3-EXPERIMENTAL:
Check if parameter can be set
/** DOM L3-EXPERIMENTAL:
     * Check if parameter can be set
     */
	public boolean canSetParameter(String name, Object state) {
		if (state == null){
			return true;
		}
		
		if (state instanceof Boolean){
			boolean value = ((Boolean)state).booleanValue();
			if (name.equalsIgnoreCase(Constants.DOM_NAMESPACES)
			|| name.equalsIgnoreCase(Constants.DOM_SPLIT_CDATA)
			|| name.equalsIgnoreCase(Constants.DOM_DISCARD_DEFAULT_CONTENT)
			|| name.equalsIgnoreCase(Constants.DOM_XMLDECL)
            || name.equalsIgnoreCase(Constants.DOM_WELLFORMED)
            || name.equalsIgnoreCase(Constants.DOM_INFOSET)
            || name.equalsIgnoreCase(Constants.DOM_ENTITIES)
            || name.equalsIgnoreCase(Constants.DOM_CDATA_SECTIONS)
            || name.equalsIgnoreCase(Constants.DOM_COMMENTS)
            || name.equalsIgnoreCase(Constants.DOM_FORMAT_PRETTY_PRINT)
            || name.equalsIgnoreCase(Constants.DOM_NAMESPACE_DECLARATIONS)){
	            // both values supported
				return true;
			}
			else if (name.equalsIgnoreCase(Constants.DOM_CANONICAL_FORM)
			    || name.equalsIgnoreCase(Constants.DOM_VALIDATE_IF_SCHEMA)
			    || name.equalsIgnoreCase(Constants.DOM_VALIDATE)
			    || name.equalsIgnoreCase(Constants.DOM_CHECK_CHAR_NORMALIZATION)
			    || name.equalsIgnoreCase(Constants.DOM_DATATYPE_NORMALIZATION)
			    || name.equalsIgnoreCase(Constants.DOM_NORMALIZE_CHARACTERS)) {
				// true is not supported
				return !value;
			}
			else if (name.equalsIgnoreCase(Constants.DOM_ELEMENT_CONTENT_WHITESPACE)
			        || name.equalsIgnoreCase(Constants.DOM_IGNORE_UNKNOWN_CHARACTER_DENORMALIZATIONS)) {
				// false is not supported
				return value;
			        }
		}
		else if (name.equalsIgnoreCase(Constants.DOM_ERROR_HANDLER) &&
				state == null || state instanceof DOMErrorHandler){
			return true;
		}
	    return false;
    }

    
 DOM Level 3 Core CR - Experimental.
 The list of the parameters supported by this 
DOMConfiguration object and for which at least one value 
can be set by the application. Note that this list can also contain 
parameter names defined outside this specification. 
/**
     *  DOM Level 3 Core CR - Experimental.
     * 
     *  The list of the parameters supported by this 
     * <code>DOMConfiguration</code> object and for which at least one value 
     * can be set by the application. Note that this list can also contain 
     * parameter names defined outside this specification. 
     */
    public DOMStringList getParameterNames() {
    	
     	if (fRecognizedParameters == null){
			ArrayList parameters = new ArrayList();

			//Add DOM recognized parameters
			//REVISIT: Would have been nice to have a list of 
			//recognized parameters.
			parameters.add(Constants.DOM_NAMESPACES);
			parameters.add(Constants.DOM_SPLIT_CDATA);
			parameters.add(Constants.DOM_DISCARD_DEFAULT_CONTENT);
			parameters.add(Constants.DOM_XMLDECL);
			parameters.add(Constants.DOM_CANONICAL_FORM);
			parameters.add(Constants.DOM_VALIDATE_IF_SCHEMA);
			parameters.add(Constants.DOM_VALIDATE);
			parameters.add(Constants.DOM_CHECK_CHAR_NORMALIZATION);
			parameters.add(Constants.DOM_DATATYPE_NORMALIZATION);
			parameters.add(Constants.DOM_FORMAT_PRETTY_PRINT);
			parameters.add(Constants.DOM_NORMALIZE_CHARACTERS);
			parameters.add(Constants.DOM_WELLFORMED);
			parameters.add(Constants.DOM_INFOSET);
			parameters.add(Constants.DOM_NAMESPACE_DECLARATIONS);
			parameters.add(Constants.DOM_ELEMENT_CONTENT_WHITESPACE);
			parameters.add(Constants.DOM_ENTITIES);
			parameters.add(Constants.DOM_CDATA_SECTIONS);
			parameters.add(Constants.DOM_COMMENTS);
			parameters.add(Constants.DOM_IGNORE_UNKNOWN_CHARACTER_DENORMALIZATIONS);
			parameters.add(Constants.DOM_ERROR_HANDLER);
			//parameters.add(Constants.DOM_SCHEMA_LOCATION);
			//parameters.add(Constants.DOM_SCHEMA_TYPE);
			
			//Add recognized xerces features and properties
			
			fRecognizedParameters = new DOMStringListImpl(parameters);		
    		
    	}

    	return fRecognizedParameters; 	
    }	
    
    
DOM L3-EXPERIMENTAL:
Getter for boolean and object parameters
/** DOM L3-EXPERIMENTAL:
     * Getter for boolean and object parameters
     */
    public Object getParameter(String name) throws DOMException {
        if (name.equalsIgnoreCase(Constants.DOM_COMMENTS)) {
            return ((features & COMMENTS) != 0) ? Boolean.TRUE : Boolean.FALSE;
        } else if (name.equalsIgnoreCase(Constants.DOM_NAMESPACES)) {
            return (features & NAMESPACES) != 0 ? Boolean.TRUE : Boolean.FALSE;
        } else if (name.equalsIgnoreCase(Constants.DOM_XMLDECL)) {
            return (features & XMLDECL) != 0 ? Boolean.TRUE : Boolean.FALSE;
        } else if (name.equalsIgnoreCase(Constants.DOM_CDATA_SECTIONS)) {
            return (features & CDATA) != 0 ? Boolean.TRUE : Boolean.FALSE;
        } else if (name.equalsIgnoreCase(Constants.DOM_ENTITIES)) {
            return (features & ENTITIES) != 0 ? Boolean.TRUE : Boolean.FALSE;
        } else if (name.equalsIgnoreCase(Constants.DOM_SPLIT_CDATA)) {
            return (features & SPLITCDATA) != 0 ? Boolean.TRUE : Boolean.FALSE;
        } else if (name.equalsIgnoreCase(Constants.DOM_WELLFORMED)) {
            return (features & WELLFORMED) != 0 ? Boolean.TRUE : Boolean.FALSE;
        } else if (name.equalsIgnoreCase(Constants.DOM_NAMESPACE_DECLARATIONS)) {
            return (features & NSDECL) != 0 ? Boolean.TRUE : Boolean.FALSE;            
        } else if (name.equalsIgnoreCase(Constants.DOM_ELEMENT_CONTENT_WHITESPACE) ||
                   name.equalsIgnoreCase(Constants.DOM_IGNORE_UNKNOWN_CHARACTER_DENORMALIZATIONS)) {
            return Boolean.TRUE;
        }else if (name.equalsIgnoreCase(Constants.DOM_DISCARD_DEFAULT_CONTENT)){
            return ((features & DISCARDDEFAULT)!=0)?Boolean.TRUE:Boolean.FALSE;
        }else if (name.equalsIgnoreCase(Constants.DOM_FORMAT_PRETTY_PRINT)){
          return ((features & PRETTY_PRINT)!=0)?Boolean.TRUE:Boolean.FALSE;
        }else if (name.equalsIgnoreCase(Constants.DOM_INFOSET)){
            if ((features & ENTITIES) == 0 &&
                 (features & CDATA) == 0 &&
                 (features & NAMESPACES) != 0 &&
                 (features & NSDECL) != 0 &&
                 (features & WELLFORMED) != 0 &&
                 (features & COMMENTS) != 0) {
                     return Boolean.TRUE;
                 }                 
                 return Boolean.FALSE;
        } else if (name.equalsIgnoreCase(Constants.DOM_NORMALIZE_CHARACTERS)
                || name.equalsIgnoreCase(Constants.DOM_CANONICAL_FORM)
                || name.equalsIgnoreCase(Constants.DOM_VALIDATE_IF_SCHEMA)
                || name.equalsIgnoreCase(Constants.DOM_CHECK_CHAR_NORMALIZATION)
                || name.equalsIgnoreCase(Constants.DOM_VALIDATE)
                || name.equalsIgnoreCase(Constants.DOM_VALIDATE_IF_SCHEMA)
                || name.equalsIgnoreCase(Constants.DOM_DATATYPE_NORMALIZATION)) {
            return Boolean.FALSE;
        } else if (name.equalsIgnoreCase(Constants.DOM_ERROR_HANDLER)) {
            return fErrorHandler;
        } else if (
            name.equalsIgnoreCase(Constants.DOM_RESOURCE_RESOLVER)
                || name.equalsIgnoreCase(Constants.DOM_SCHEMA_LOCATION)
                || name.equalsIgnoreCase(Constants.DOM_SCHEMA_TYPE)) {
            String msg =
                DOMMessageFormatter.formatMessage(
                    DOMMessageFormatter.DOM_DOMAIN,
                    "FEATURE_NOT_SUPPORTED",
                    new Object[] { name });
            throw new DOMException(DOMException.NOT_SUPPORTED_ERR, msg);
        } else {
            String msg =
                DOMMessageFormatter.formatMessage(
                    DOMMessageFormatter.DOM_DOMAIN,
                    "FEATURE_NOT_FOUND",
                    new Object[] { name });
            throw new DOMException(DOMException.NOT_FOUND_ERR, msg);
        }
    }


    
DOM L3 EXPERIMENTAL:
 Serialize the specified node as described above in the description of
LSSerializer. The result of serializing the node is
returned as a string. Writing a Document or Entity node produces a
serialized form that is well formed XML. Writing other node types
produces a fragment of text in a form that is not fully defined by
this document, but that should be useful to a human for debugging or
diagnostic purposes.
Params:
wnode –  The node to be written.
Throws:
DOMException – 
   DOMSTRING_SIZE_ERR: The resulting string is too long to fit in a
  DOMString.
LSException – 
   SERIALIZE_ERR: Unable to serialize the node.  DOM applications should
   attach a DOMErrorHandler using the parameter 
   "error-handler" to get details on error.
Returns:
 Returns the serialized data/**
     * DOM L3 EXPERIMENTAL:
     *  Serialize the specified node as described above in the description of
     * <code>LSSerializer</code>. The result of serializing the node is
     * returned as a string. Writing a Document or Entity node produces a
     * serialized form that is well formed XML. Writing other node types
     * produces a fragment of text in a form that is not fully defined by
     * this document, but that should be useful to a human for debugging or
     * diagnostic purposes.
     * @param wnode  The node to be written.
     * @return  Returns the serialized data
     * @exception DOMException
     *    DOMSTRING_SIZE_ERR: The resulting string is too long to fit in a
     *   <code>DOMString</code>.
     * @exception LSException
     *    SERIALIZE_ERR: Unable to serialize the node.  DOM applications should
     *    attach a <code>DOMErrorHandler</code> using the parameter 
     *    &quot;<i>error-handler</i>&quot; to get details on error.
     */
    public String writeToString(Node wnode) throws DOMException, LSException {
        // determine which serializer to use:
        XMLSerializer ser = null;
        String ver = _getXmlVersion(wnode);
        if (ver != null && ver.equals("1.1")) {
            if(xml11Serializer == null) {
                xml11Serializer = new XML11Serializer();
                initSerializer(xml11Serializer);
            }
            // copy setting from "main" serializer to XML 1.1 serializer
            copySettings(serializer, xml11Serializer);
            ser = xml11Serializer;
        } 
        else {
            ser = serializer;
        }

        StringWriter destination = new StringWriter();
        try {
            prepareForSerialization(ser, wnode);
            ser._format.setEncoding("UTF-16");
            ser.setOutputCharStream(destination);
            if (wnode.getNodeType() == Node.DOCUMENT_NODE) {
                ser.serialize((Document)wnode);
            }
            else if (wnode.getNodeType() == Node.DOCUMENT_FRAGMENT_NODE) {
                ser.serialize((DocumentFragment)wnode);
            }
            else if (wnode.getNodeType() == Node.ELEMENT_NODE) {
                ser.serialize((Element)wnode);
            }
            else {
                String msg = DOMMessageFormatter.formatMessage(
                    DOMMessageFormatter.SERIALIZER_DOMAIN, 
                    "unable-to-serialize-node", null);
                if (ser.fDOMErrorHandler != null) {
                    DOMErrorImpl error = new DOMErrorImpl();
                    error.fType = "unable-to-serialize-node";
                    error.fMessage = msg;
                    error.fSeverity = DOMError.SEVERITY_FATAL_ERROR;
                    ser.fDOMErrorHandler.handleError(error);
                }
                throw new LSException(LSException.SERIALIZE_ERR, msg);
            }
        } 
        catch (LSException lse) {
            // Rethrow LSException.
            throw lse;
        } 
        catch (RuntimeException e) {
            if (e == DOMNormalizer.abort){
                // stopped at user request
                return null;
            }
            throw (LSException) DOMUtil.createLSException(LSException.SERIALIZE_ERR, e).fillInStackTrace();       
        } 
        catch (IOException ioe) {
            // REVISIT: A generic IOException doesn't provide enough information
            // to determine that the serialized document is too large to fit
            // into a string. This could have thrown for some other reason. -- mrglavas
            String msg = DOMMessageFormatter.formatMessage(
                DOMMessageFormatter.DOM_DOMAIN,
                "STRING_TOO_LONG",
                new Object[] { ioe.getMessage()});
            throw new DOMException(DOMException.DOMSTRING_SIZE_ERR,msg);
        }
        finally {
            ser.clearDocumentState();
        }
        return destination.toString();
    }

    
DOM L3 EXPERIMENTAL:
The end-of-line sequence of characters to be used in the XML being
written out. The only permitted values are these:

null

Use a default end-of-line sequence. DOM implementations should choose
the default to match the usual convention for text files in the
environment being used. Implementations must choose a default
sequence that matches one of those allowed by  2.11 "End-of-Line
Handling". 
CR
The carriage-return character (#xD).
CR-LF
 The
carriage-return and line-feed characters (#xD #xA). 
LF
 The line-feed
character (#xA). 


The default value for this attribute is null.
/**
     * DOM L3 EXPERIMENTAL:
     * The end-of-line sequence of characters to be used in the XML being
     * written out. The only permitted values are these:
     * <dl>
     * <dt><code>null</code></dt>
     * <dd>
     * Use a default end-of-line sequence. DOM implementations should choose
     * the default to match the usual convention for text files in the
     * environment being used. Implementations must choose a default
     * sequence that matches one of those allowed by  2.11 "End-of-Line
     * Handling". </dd>
     * <dt>CR</dt>
     * <dd>The carriage-return character (#xD).</dd>
     * <dt>CR-LF</dt>
     * <dd> The
     * carriage-return and line-feed characters (#xD #xA). </dd>
     * <dt>LF</dt>
     * <dd> The line-feed
     * character (#xA). </dd>
     * </dl>
     * <br>The default value for this attribute is <code>null</code>.
     */
    public void setNewLine(String newLine) {
        serializer._format.setLineSeparator(newLine);
    }


    
DOM L3 EXPERIMENTAL:
The end-of-line sequence of characters to be used in the XML being
written out. The only permitted values are these:

null

Use a default end-of-line sequence. DOM implementations should choose
the default to match the usual convention for text files in the
environment being used. Implementations must choose a default
sequence that matches one of those allowed by  2.11 "End-of-Line
Handling". 
CR
The carriage-return character (#xD).
CR-LF
 The
carriage-return and line-feed characters (#xD #xA). 
LF
 The line-feed
character (#xA). 


The default value for this attribute is null.
/**
     * DOM L3 EXPERIMENTAL:
     * The end-of-line sequence of characters to be used in the XML being
     * written out. The only permitted values are these:
     * <dl>
     * <dt><code>null</code></dt>
     * <dd>
     * Use a default end-of-line sequence. DOM implementations should choose
     * the default to match the usual convention for text files in the
     * environment being used. Implementations must choose a default
     * sequence that matches one of those allowed by  2.11 "End-of-Line
     * Handling". </dd>
     * <dt>CR</dt>
     * <dd>The carriage-return character (#xD).</dd>
     * <dt>CR-LF</dt>
     * <dd> The
     * carriage-return and line-feed characters (#xD #xA). </dd>
     * <dt>LF</dt>
     * <dd> The line-feed
     * character (#xA). </dd>
     * </dl>
     * <br>The default value for this attribute is <code>null</code>.
     */
    public String getNewLine() {
        return serializer._format.getLineSeparator();
    }


    
 When the application provides a filter, the serializer will call out
to the filter before serializing each Node. Attribute nodes are never
passed to the filter. The filter implementation can choose to remove
the node from the stream or to terminate the serialization early.
/**
     *  When the application provides a filter, the serializer will call out
     * to the filter before serializing each Node. Attribute nodes are never
     * passed to the filter. The filter implementation can choose to remove
     * the node from the stream or to terminate the serialization early.
     */
    public LSSerializerFilter getFilter(){
        return serializer.fDOMFilter;
    }
    
 When the application provides a filter, the serializer will call out
to the filter before serializing each Node. Attribute nodes are never
passed to the filter. The filter implementation can choose to remove
the node from the stream or to terminate the serialization early.
/**
     *  When the application provides a filter, the serializer will call out
     * to the filter before serializing each Node. Attribute nodes are never
     * passed to the filter. The filter implementation can choose to remove
     * the node from the stream or to terminate the serialization early.
     */
    public void setFilter(LSSerializerFilter filter){
        serializer.fDOMFilter = filter;
    }

    // this initializes a newly-created serializer
    private void initSerializer(XMLSerializer ser) {
        ser.fNSBinder = new NamespaceSupport();
        ser.fLocalNSBinder = new NamespaceSupport();
        ser.fSymbolTable = new SymbolTable();	
    }

    // copies all settings that could have been modified
    // by calls to LSSerializer methods from one serializer to another.
    // IMPORTANT:  if new methods are implemented or more settings of
    // the serializer are made alterable, this must be
    // reflected in this method!
    private void copySettings(XMLSerializer src, XMLSerializer dest) {
        dest.fDOMErrorHandler = fErrorHandler;
        dest._format.setEncoding(src._format.getEncoding());
        dest._format.setLineSeparator(src._format.getLineSeparator());
        dest.fDOMFilter = src.fDOMFilter;
    }//copysettings

    
 Serialize the specified node as described above in the general
description of the LSSerializer interface. The output
is written to the supplied LSOutput.

 When writing to a LSOutput, the encoding is found by
looking at the encoding information that is reachable through the
LSOutput and the item to be written (or its owner
document) in this order:

 LSOutput.encoding,


Document.actualEncoding,


Document.xmlEncoding.



 If no encoding is reachable through the above properties, a
default encoding of "UTF-8" will be used.

 If the specified encoding is not supported an
"unsupported-encoding" error is raised.

 If no output is specified in the LSOutput, a
"no-output-specified" error is raised.
Params:
node –  The node to serialize.
destination – The destination for the serialized DOM.
Returns:
 Returns true if node was
  successfully serialized and false in case the node
  couldn't be serialized./**
      *  Serialize the specified node as described above in the general
      * description of the <code>LSSerializer</code> interface. The output
      * is written to the supplied <code>LSOutput</code>.
      * <br> When writing to a <code>LSOutput</code>, the encoding is found by
      * looking at the encoding information that is reachable through the
      * <code>LSOutput</code> and the item to be written (or its owner
      * document) in this order:
      * <ol>
      * <li> <code>LSOutput.encoding</code>,
      * </li>
      * <li>
      * <code>Document.actualEncoding</code>,
      * </li>
      * <li>
      * <code>Document.xmlEncoding</code>.
      * </li>
      * </ol>
      * <br> If no encoding is reachable through the above properties, a
      * default encoding of "UTF-8" will be used.
      * <br> If the specified encoding is not supported an
      * "unsupported-encoding" error is raised.
      * <br> If no output is specified in the <code>LSOutput</code>, a
      * "no-output-specified" error is raised.
      * @param node  The node to serialize.
      * @param destination The destination for the serialized DOM.
      * @return  Returns <code>true</code> if <code>node</code> was
      *   successfully serialized and <code>false</code> in case the node
      *   couldn't be serialized.
      */
    public boolean write(Node node, LSOutput destination) throws LSException{

        if (node == null)
            return false;

        XMLSerializer ser = null;
        String ver = _getXmlVersion(node);
        //determine which serializer to use:
        if (ver != null && ver.equals("1.1")) {
            if (xml11Serializer == null) {
                xml11Serializer = new XML11Serializer();
                initSerializer(xml11Serializer);
            }
            //copy setting from "main" serializer to XML 1.1 serializer
            copySettings(serializer, xml11Serializer);
            ser = xml11Serializer;
        } 
        else {
            ser = serializer;
        }

        String encoding = null;
        if ((encoding = destination.getEncoding()) == null) {
            encoding = _getInputEncoding(node);
            if (encoding == null) {
                encoding = _getXmlEncoding(node);
                if (encoding == null) {
                    encoding = "UTF-8";
                }
            }
        }
        try {
            prepareForSerialization(ser, node);
            ser._format.setEncoding(encoding);
            OutputStream outputStream = destination.getByteStream();
            Writer writer = destination.getCharacterStream();
            String uri =  destination.getSystemId();
            if (writer == null) {
                if (outputStream == null) {
                    if (uri == null) {
                        String msg = DOMMessageFormatter.formatMessage(
                            DOMMessageFormatter.SERIALIZER_DOMAIN, 
                            "no-output-specified", null);
                        if (ser.fDOMErrorHandler != null) {
                            DOMErrorImpl error = new DOMErrorImpl();
                            error.fType = "no-output-specified";
                            error.fMessage = msg;
                            error.fSeverity = DOMError.SEVERITY_FATAL_ERROR;
                            ser.fDOMErrorHandler.handleError(error);
                        }
                        throw new LSException(LSException.SERIALIZE_ERR, msg);
                    }
                    else {
                        ser.setOutputByteStream(XMLEntityManager.createOutputStream(uri));
                    }
                }
                else {
                    // byte stream was specified
                    ser.setOutputByteStream(outputStream);
                }
            }
            else {
                // character stream is specified
                ser.setOutputCharStream(writer); 
            }

            if (node.getNodeType() == Node.DOCUMENT_NODE)
                ser.serialize((Document) node);
            else if (node.getNodeType() == Node.DOCUMENT_FRAGMENT_NODE)
                ser.serialize((DocumentFragment) node);
            else if (node.getNodeType() == Node.ELEMENT_NODE)
                ser.serialize((Element) node);
            else
                return false;
        } 
        catch( UnsupportedEncodingException ue) {
            if (ser.fDOMErrorHandler != null) {
                DOMErrorImpl error = new DOMErrorImpl();
                error.fException = ue;
				error.fType = "unsupported-encoding";
                error.fMessage = ue.getMessage();
				error.fSeverity = DOMError.SEVERITY_FATAL_ERROR;
                ser.fDOMErrorHandler.handleError(error);
			}
            throw new LSException(LSException.SERIALIZE_ERR, 
                DOMMessageFormatter.formatMessage(
                    DOMMessageFormatter.SERIALIZER_DOMAIN, 
                    "unsupported-encoding", null));			
			//return false;
        } 
        catch (LSException lse) {
            // Rethrow LSException.
            throw lse;
        } 
        catch (RuntimeException e) {
            if (e == DOMNormalizer.abort){
                // stopped at user request
                return false;
            }
            throw (LSException) DOMUtil.createLSException(LSException.SERIALIZE_ERR, e).fillInStackTrace();
        } 
        catch (Exception e) {
            if (ser.fDOMErrorHandler != null) {
                DOMErrorImpl error = new DOMErrorImpl();
                error.fException = e;
                error.fMessage = e.getMessage();
                error.fSeverity = DOMError.SEVERITY_ERROR;
                ser.fDOMErrorHandler.handleError(error);

            }
            throw (LSException) DOMUtil.createLSException(LSException.SERIALIZE_ERR, e).fillInStackTrace();
        }
        finally {
            ser.clearDocumentState();
        }
        return true;

    } //write

    
 Serialize the specified node as described above in the general
description of the LSSerializer interface. The output
is written to the supplied URI.

 When writing to a URI, the encoding is found by looking at the
encoding information that is reachable through the item to be written
(or its owner document) in this order:


Document.inputEncoding,


Document.xmlEncoding.



 If no encoding is reachable through the above properties, a
default encoding of "UTF-8" will be used.

 If the specified encoding is not supported an
"unsupported-encoding" error is raised.
Params:
node –  The node to serialize.
URI – The URI to write to.
Returns:
 Returns true if node was
  successfully serialized and false in case the node
  couldn't be serialized./**
      *  Serialize the specified node as described above in the general
      * description of the <code>LSSerializer</code> interface. The output
      * is written to the supplied URI.
      * <br> When writing to a URI, the encoding is found by looking at the
      * encoding information that is reachable through the item to be written
      * (or its owner document) in this order:
      * <ol>
      * <li>
      * <code>Document.inputEncoding</code>,
      * </li>
      * <li>
      * <code>Document.xmlEncoding</code>.
      * </li>
      * </ol>
      * <br> If no encoding is reachable through the above properties, a
      * default encoding of "UTF-8" will be used.
      * <br> If the specified encoding is not supported an
      * "unsupported-encoding" error is raised.
      * @param node  The node to serialize.
      * @param URI The URI to write to.
      * @return  Returns <code>true</code> if <code>node</code> was
      *   successfully serialized and <code>false</code> in case the node
      *   couldn't be serialized.
      */
    public boolean writeToURI(Node node, String URI) throws LSException{
        if (node == null){
            return false;
        }

        XMLSerializer ser = null;
        String ver = _getXmlVersion(node);

        if (ver != null && ver.equals("1.1")) {
            if (xml11Serializer == null) {
                xml11Serializer = new XML11Serializer();
                initSerializer(xml11Serializer);
            }
            // copy setting from "main" serializer to XML 1.1 serializer
            copySettings(serializer, xml11Serializer);
            ser = xml11Serializer;
        } 
        else {
            ser = serializer;
        }        

        String encoding = _getInputEncoding(node);
        if (encoding == null) {
            encoding = _getXmlEncoding(node);
            if (encoding == null) {
                encoding = "UTF-8";
            }
        }

        try {
            prepareForSerialization(ser, node);
            ser._format.setEncoding(encoding);
            ser.setOutputByteStream(XMLEntityManager.createOutputStream(URI));

            if (node.getNodeType() == Node.DOCUMENT_NODE)
                ser.serialize((Document) node);
            else if (node.getNodeType() == Node.DOCUMENT_FRAGMENT_NODE)
                ser.serialize((DocumentFragment) node);
            else if (node.getNodeType() == Node.ELEMENT_NODE)
                ser.serialize((Element) node);
            else
                return false;
        } 
        catch (LSException lse) {
            // Rethrow LSException.
            throw lse;
        } 
        catch (RuntimeException e) {
            if (e == DOMNormalizer.abort){
                // stopped at user request
                return false;
            }
            throw (LSException) DOMUtil.createLSException(LSException.SERIALIZE_ERR, e).fillInStackTrace();
        } 
        catch (Exception e) {
            if (ser.fDOMErrorHandler != null) {
                DOMErrorImpl error = new DOMErrorImpl();
                error.fException = e;
                error.fMessage = e.getMessage();
                error.fSeverity = DOMError.SEVERITY_ERROR;
                ser.fDOMErrorHandler.handleError(error);
            }
            throw (LSException) DOMUtil.createLSException(LSException.SERIALIZE_ERR, e).fillInStackTrace();
        }
        finally {
            ser.clearDocumentState();
        }
        return true;
    } //writeURI
    
    
    //
    //  Private methods
    //

    private void prepareForSerialization(XMLSerializer ser, Node node) {
        ser.reset();
        ser.features = features;
        ser.fDOMErrorHandler = fErrorHandler;
        ser.fNamespaces = (features & NAMESPACES) != 0;
        ser.fNamespacePrefixes = (features & NSDECL) != 0;
        ser._format.setIndenting((features & PRETTY_PRINT) != 0);
        ser._format.setOmitComments((features & COMMENTS)==0);
        ser._format.setOmitXMLDeclaration((features & XMLDECL) == 0);   
 
        if ((features & WELLFORMED) != 0) {
            // REVISIT: this is inefficient implementation of well-formness. Instead, we should check
            // well-formness as we serialize the tree
            Node next, root;
            root = node;
            Method versionChanged;
            boolean verifyNames = true;
            Document document =(node.getNodeType() == Node.DOCUMENT_NODE)
                    ? (Document) node
                    : node.getOwnerDocument();
            try {
                versionChanged = document.getClass().getMethod("isXMLVersionChanged()", new Class[] {});
                if (versionChanged != null) {
                    verifyNames = ((Boolean)versionChanged.invoke(document, (Object[]) null)).booleanValue();
                }
            } catch (Exception e) {
                //no way to test the version...
                //ignore the exception
            }
            if (node.getFirstChild() != null) {
                while (node != null) {
                    verify(node, verifyNames, false);
                    // Move down to first child
                    next = node.getFirstChild();
                    // No child nodes, so walk tree
                    while (next == null) {
                      // Move to sibling if possible.
                      next = node.getNextSibling();
                      if (next == null) {
                          node = node.getParentNode();
                          if (root == node){
                              next = null;
                              break;                   
                          }
                          next = node.getNextSibling();
                      }
                    }
                    node = next;
                }
            }
            else {
                verify(node, verifyNames, false);
            }
        }
    }
    
    
    private void verify (Node node, boolean verifyNames, boolean xml11Version){

        int type = node.getNodeType();
        fLocator.fRelatedNode = node;
        boolean wellformed;
        switch (type) { 
            case Node.DOCUMENT_NODE:{
                break;
            }
            case Node.DOCUMENT_TYPE_NODE:{
                break;
            }
            case Node.ELEMENT_NODE:{               
                if (verifyNames){
                    if((features & NAMESPACES) != 0){
                        wellformed = CoreDocumentImpl.isValidQName(node.getPrefix() , node.getLocalName(), xml11Version) ;
                    }
                    else{
                        wellformed = CoreDocumentImpl.isXMLName(node.getNodeName() , xml11Version);
                    }
                    if (!wellformed){
                        if (fErrorHandler != null) {
                            String msg = DOMMessageFormatter.formatMessage(
                                    DOMMessageFormatter.DOM_DOMAIN, 
                                    "wf-invalid-character-in-node-name", 
                                    new Object[]{"Element", node.getNodeName()});
                            DOMNormalizer.reportDOMError(fErrorHandler, fError, fLocator, msg, DOMError.SEVERITY_FATAL_ERROR, 
                            "wf-invalid-character-in-node-name");
                        }                        
                    }                       
                }
                
                NamedNodeMap attributes = (node.hasAttributes()) ? node.getAttributes() : null; 
                if (attributes != null) {
                    for (int i = 0; i < attributes.getLength(); ++i) {
                        Attr attr = (Attr) attributes.item(i);
                        fLocator.fRelatedNode = attr;
                        DOMNormalizer.isAttrValueWF( fErrorHandler, fError, fLocator, 
                                      attributes, attr, attr.getValue(), xml11Version);
                        if (verifyNames) {
                            wellformed = CoreDocumentImpl.isXMLName( attr.getNodeName(), xml11Version);
                            if (!wellformed) {
                                    String msg =
                                        DOMMessageFormatter.formatMessage(
                                            DOMMessageFormatter.DOM_DOMAIN,
                                            "wf-invalid-character-in-node-name",
                                            new Object[] { "Attr", node.getNodeName()});
                                    DOMNormalizer.reportDOMError( fErrorHandler, fError, fLocator, msg, DOMError.SEVERITY_FATAL_ERROR,
                                        "wf-invalid-character-in-node-name");
                            }
                        }
                    }

                }
                
                break;
            }
        
        case Node.COMMENT_NODE: {
            // only verify well-formness if comments included in the tree
            if ((features & COMMENTS) != 0)
                DOMNormalizer.isCommentWF(fErrorHandler, fError, fLocator, ((Comment)node).getData(), xml11Version);
            break;
        }
        case Node.ENTITY_REFERENCE_NODE: {
            // only if entity is preserved in the tree
            if (verifyNames && (features & ENTITIES) != 0){
                CoreDocumentImpl.isXMLName(node.getNodeName() , xml11Version);
            }
            break;
            
        }
        case Node.CDATA_SECTION_NODE: {
            // verify content
            DOMNormalizer.isXMLCharWF(fErrorHandler, fError, fLocator, node.getNodeValue(), xml11Version);
            // the ]]> string will be checked during serialization
            break;
        }
        case Node.TEXT_NODE:{
            DOMNormalizer.isXMLCharWF(fErrorHandler, fError, fLocator, node.getNodeValue(), xml11Version);
            break;
        }
        case Node.PROCESSING_INSTRUCTION_NODE:{
            ProcessingInstruction pinode = (ProcessingInstruction)node ;
            String target = pinode.getTarget();
            if (verifyNames) {
                if (xml11Version) {
                    wellformed = XML11Char.isXML11ValidName(target);
                } else {
                    wellformed = XMLChar.isValidName(target);
                }

                if (!wellformed) {
                    String msg =
                        DOMMessageFormatter.formatMessage(
                            DOMMessageFormatter.DOM_DOMAIN,
                            "wf-invalid-character-in-node-name",
                            new Object[] { "Element", node.getNodeName()});
                    DOMNormalizer.reportDOMError(
                        fErrorHandler,
                        fError,
                        fLocator,
                        msg,
                        DOMError.SEVERITY_FATAL_ERROR,
                        "wf-invalid-character-in-node-name");
                }
            }              
            DOMNormalizer.isXMLCharWF(fErrorHandler, fError, fLocator, pinode.getData(), xml11Version);
            break;
        }        
        }
        fLocator.fRelatedNode = null;
    }
    
    private String _getXmlVersion(Node node) {
        Document doc = (node.getNodeType() == Node.DOCUMENT_NODE) ? 
                (Document) node : node.getOwnerDocument();
        if (doc != null && DocumentMethods.fgDocumentMethodsAvailable) {
            try {
                return (String) DocumentMethods.fgDocumentGetXmlVersionMethod.invoke(doc, (Object[]) null);
            }
            // The VM ran out of memory or there was some other serious problem. Re-throw.
            catch (VirtualMachineError vme) {
                throw vme;
            }
            // ThreadDeath should always be re-thrown
            catch (ThreadDeath td) {
                throw td;
            }
            // Ignore all other exceptions and errors
            catch (Throwable t) {}
        }
        return null;
    }

    private String _getInputEncoding(Node node) {
        Document doc = (node.getNodeType() == Node.DOCUMENT_NODE) ? 
                (Document) node : node.getOwnerDocument();
        if (doc != null && DocumentMethods.fgDocumentMethodsAvailable) {
            try {
                return (String) DocumentMethods.fgDocumentGetInputEncodingMethod.invoke(doc, (Object[]) null);
            }
            // The VM ran out of memory or there was some other serious problem. Re-throw.
            catch (VirtualMachineError vme) {
                throw vme;
            }
            // ThreadDeath should always be re-thrown
            catch (ThreadDeath td) {
                throw td;
            }
            // Ignore all other exceptions and errors
            catch (Throwable t) {}
        }
        return null;
    }
    
    private String _getXmlEncoding(Node node) {
        Document doc = (node.getNodeType() == Node.DOCUMENT_NODE) ? 
                (Document) node : node.getOwnerDocument();
        if (doc != null && DocumentMethods.fgDocumentMethodsAvailable) {
            try {
                return (String) DocumentMethods.fgDocumentGetXmlEncodingMethod.invoke(doc, (Object[]) null);
            }
            // The VM ran out of memory or there was some other serious problem. Re-throw.
            catch (VirtualMachineError vme) {
                throw vme;
            }
            // ThreadDeath should always be re-thrown
            catch (ThreadDeath td) {
                throw td;
            }
            // Ignore all other exceptions and errors
            catch (Throwable t) {}
        }
        return null;
    }
    
    
Holder of DOM Level 3 methods from org.w3c.dom.Document.
/**
     * Holder of DOM Level 3 methods from org.w3c.dom.Document.
     */
    static class DocumentMethods {
        
        // Method: org.w3c.dom.Document.getXmlVersion()
        private static java.lang.reflect.Method fgDocumentGetXmlVersionMethod = null;
        
        // Method: org.w3c.dom.Document.getInputEncoding()
        private static java.lang.reflect.Method fgDocumentGetInputEncodingMethod = null;
        
        // Method: org.w3c.dom.Document.getXmlEncoding()
        private static java.lang.reflect.Method fgDocumentGetXmlEncodingMethod = null;
        
        // Flag indicating whether or not Document methods are available.
        private static boolean fgDocumentMethodsAvailable = false;
        
        private DocumentMethods() {}
        
        // Attempt to get methods for org.w3c.dom.Document on class initialization.
        static {
            try {
                fgDocumentGetXmlVersionMethod = Document.class.getMethod("getXmlVersion", new Class [] {});
                fgDocumentGetInputEncodingMethod = Document.class.getMethod("getInputEncoding", new Class [] {});
                fgDocumentGetXmlEncodingMethod = Document.class.getMethod("getXmlEncoding", new Class [] {});
                fgDocumentMethodsAvailable = true;
            }
            // ClassNotFoundException, NoSuchMethodException or SecurityException
            // Whatever the case, we cannot retrieve the methods.
            catch (Exception exc) {
                fgDocumentGetXmlVersionMethod = null;
                fgDocumentGetInputEncodingMethod = null;
                fgDocumentGetXmlEncodingMethod = null;
                fgDocumentMethodsAvailable = false;
            }
        }
    }

} //DOMSerializerImpl