/*
 * 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 <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 $Id$
 * 
 * @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. 
     */
    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 <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
     */
    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
     */
	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 
     * <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
     */
    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
     * <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:
     * <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:
     * <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.
     */
    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.
     */
    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 <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 <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.
     */
    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