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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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 * accompanied this code).
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package com.sun.xml.internal.stream.writers;

import java.io.FileWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.nio.charset.Charset;
import java.nio.charset.CharsetEncoder;
import jdk.xml.internal.SecuritySupport;

Implements common xml writer functions.
Author:
Neeraj Bajaj,K.Venugopal Sun Microsystems./**
 * Implements common xml writer functions.
 *
 * @author Neeraj Bajaj,K.Venugopal Sun Microsystems.
 */

public class WriterUtility {


    public static final String START_COMMENT = "<!--";
    public static final String END_COMMENT = "-->";
    public static final String DEFAULT_ENCODING = " encoding=\"utf-8\"";
    public static final String DEFAULT_XMLDECL ="<?xml version=\"1.0\" ?>";
    public static final String DEFAULT_XML_VERSION ="1.0";
    public static final char CLOSE_START_TAG = '>';
    public static final char OPEN_START_TAG = '<';
    public static final String OPEN_END_TAG ="</";
    public static final char CLOSE_END_TAG = '>';
    public static final String START_CDATA = "<![CDATA[";
    public static final String END_CDATA = "]]>";
    public static final String CLOSE_EMPTY_ELEMENT = "/>";
    public static final String SPACE = " ";
    public static final String UTF_8 = "utf-8";

    static final boolean DEBUG_XML_CONTENT = false;

    
XXX: This feature is only used when writing element content values.
default value is 'true' however, if the feature is set to false
characters wont be escaped.
This feature has no effect when writing Attribute values, character would still be escaped.
I can't think of any reason why this would be useful when writing attribute values.
However, this can be reconsidered if there is any usecase.
/**XXX: This feature is only used when writing element content values.
     * default value is 'true' however, if the feature is set to false
     * characters wont be escaped.
     * This feature has no effect when writing Attribute values, character would still be escaped.
     * I can't think of any reason why this would be useful when writing attribute values.
     * However, this can be reconsidered if there is any usecase.
     */
    boolean fEscapeCharacters = true ;

    
Writer object/** Writer object*/
    Writer fWriter = null;

    //CharsetEncoder
    CharsetEncoder fEncoder ;

    public WriterUtility(){
        fEncoder = getDefaultEncoder();
    }


    
Creates a new instance of WriterUtility /** Creates a new instance of WriterUtility */
    public WriterUtility(Writer writer) {
        fWriter = writer;
        if(writer instanceof OutputStreamWriter){
            String charset = ((OutputStreamWriter)writer).getEncoding();
            if(charset != null){
                fEncoder = Charset.forName(charset).newEncoder();
            }
        }else if(writer instanceof FileWriter){
            String charset = ((FileWriter)writer).getEncoding();
            if(charset != null){
                fEncoder = Charset.forName(charset).newEncoder();
            }
        }
        else{
            //attempt to retreive default fEncoderoder
            fEncoder = getDefaultEncoder();
        }
    }

    
sets the writer object
Params:
writer – file to write into/**
     * sets the writer object
     * @param writer file to write into
     */
    public void  setWriter(Writer writer){
        fWriter = writer;
    }

    public void setEscapeCharacters(boolean escape){
        fEscapeCharacters = escape ;
    }

    public boolean getEscapeCharacters(){
        return fEscapeCharacters;
    }

    
writes xml content (characters and element content
Params:
content – /**
     * writes xml content (characters and element content
     * @param content
     */
    public void writeXMLContent(char[] content, int start, int length) throws IOException{
        writeXMLContent(content, start, length, getEscapeCharacters());
    }

    
writes xml content (characters and element content
Params:
content – /**
     * writes xml content (characters and element content
     * @param content
     */
    private void writeXMLContent(char[] content, int start, int length, boolean escapeCharacter) throws IOException{
        if(DEBUG_XML_CONTENT){
            System.out.println("content to write is " + new String(content, start, length));
        }
        int index;
        char ch;
        int sc;
        final int end = start + length ;
        //define startWritePos to track the position from where the character array data needs to be written
        //initialize this variable to start pos. indicating that no data has been written
        int startWritePos = start;

        for ( index = start ; index < end ; index++ ) {
            ch = content[ index ];

            if(fEncoder != null && !fEncoder.canEncode(ch)){
                //- write the data to the point we get this character
                fWriter.write(content, startWritePos, index - startWritePos );

                //escape this character
                fWriter.write( "&#x" );
                fWriter.write(Integer.toHexString(ch));
                fWriter.write( ';' );
                //increase the startWritePos by 1 indicating that next write should start from
                //one position ahead
                startWritePos = index + 1;

            }
            if(DEBUG_XML_CONTENT){
                System.out.println("startWritePos = " + startWritePos);
                System.out.println("index = " + index);
                System.out.println("start = " + start);
                System.out.println("end = " + end);
            }

            switch(ch){
                case '<' :{
                    if(escapeCharacter){
                        //this character needs to be escaped, write the data from the last write pos
                        fWriter.write(content, startWritePos, index - startWritePos);
                        fWriter.write("&lt;");
                        if(DEBUG_XML_CONTENT){
                            System.out.print(new String(content, startWritePos, index - startWritePos));
                            System.out.println("&lt;");
                        }
                        //increase the startWritePos by 1 indicating that next write should start from
                        //one position ahead
                        startWritePos = index + 1;
                    }
                    break;
                }
                case '&' :{
                    if(escapeCharacter){
                        //this character needs to be escaped, write the data from the last write pos
                        fWriter.write(content, startWritePos, index - startWritePos);
                        fWriter.write("&amp;");
                        if(DEBUG_XML_CONTENT){
                            System.out.print(new String(content,startWritePos, index - startWritePos));
                            System.out.println("&amp;");
                        }
                        //increase the startWritePos by 1 indicating that next write should start from
                        //one position ahead
                        startWritePos = index + 1;
                    }
                    break;
                }

                case '>': {
                    if(escapeCharacter){
                        //this character needs to be escaped, write the data from the last write pos
                        fWriter.write(content, startWritePos, index - startWritePos);
                        fWriter.write("&gt;");
                        if(DEBUG_XML_CONTENT){
                            System.out.print(new String(content,startWritePos, index - startWritePos));
                            System.out.println("&gt;");
                        }
                        //increase the startWritePos by 1 indicating that next write should start from
                        //one position ahead
                        startWritePos = index + 1;
                    }
                    break;
                }
            }
        }
        if(DEBUG_XML_CONTENT){
            System.out.println("out of the loop, writing " + new String(content, startWritePos, end - startWritePos));
        }
        //write any pending data
        fWriter.write(content, startWritePos, end - startWritePos);
    }

    
writes xml content (characters and element content
Params:
content – /**
     * writes xml content (characters and element content
     * @param content
     */
    public void writeXMLContent(String content) throws IOException{
        if(content == null || content.length() == 0) return ;
        writeXMLContent(content.toCharArray(), 0, content.length());
    }


    
Write Attribute value to the underlying stream.
Params:
value – /**
     * Write Attribute value to the underlying stream.
     *
     * @param value
     */

    public void  writeXMLAttributeValue(String value)throws IOException{
        writeXMLContent(value.toCharArray(), 0, value.length(), true);
    }

    private CharsetEncoder getDefaultEncoder(){
        try{
            String encoding = SecuritySupport.getSystemProperty("file.encoding");
            if(encoding != null){
                return Charset.forName(encoding).newEncoder();
            }
        }
        catch(Exception ex){
            //for any exception thrown , catch and continue
        }
        return null;
    }
}