Name: nt126004 Date: 05/22/2003


FULL PRODUCT VERSION :
java version "1.4.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-b92)
Java HotSpot(TM) Client VM (build 1.4.0-b92, mixed mode)

FULL OPERATING SYSTEM VERSION :
Microsoft Windows 2000 [Version 5.00.2195]

A DESCRIPTION OF THE PROBLEM :
If you use the possibility of java.util.prefs.Preferences
to import or export preferences into or from a xml file all
new line characters of a string will be stripped.

This bug also bothers all operating systems where
the "FileSystemPreferences" are used (at least Linux).


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. create a multiline preference value
2. export it
3. import it again

EXPECTED VERSUS ACTUAL BEHAVIOR :
It was expected that the export and import preserves the
new line characters.

One possible way would be in doing some kind of escaping or
possibly configure the xmlparser in a way to do this.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
package test;

import java.io.*;
import java.util.prefs.Preferences;

public class PrefTest
{

    public static void main(String[] args)
    {
        try
        {
            String value = "value\nwith\nmultiple\nlines";
            System.out.println( "value before1: " + value );

            Preferences.userRoot().node( "test" ).put( "key", value );
            System.out.println( "value before2: " + Preferences.userRoot().node
( "test" ).get( "key", "default" ) );

            Preferences.userRoot().node( "test" ).exportSubtree( new
FileOutputStream( "some_test_file.xml" ) );
            Preferences.importPreferences( new FileInputStream
( "some_test_file.xml" ) );

            System.out.println( "value after: " + Preferences.userRoot().node
( "test" ).get( "key", "default" ) );
        }
        catch ( Exception e )
        {
            e.printStackTrace();
        }
    }
}
---------- END SOURCE ----------

CUSTOMER WORKAROUND :
do a escaping in the client code:

before put:

int len = value.length();
StringBuffer ret = new StringBuffer( len + 16 );
for ( int i = 0; i < len; i++ )
{
    char c = value.charAt( i );
    if ( c == '\n' )
    {
        ret.append( "\\n" );
    }
    else if ( c == '\\' )
    {
        ret.append( "\\\\" );
    }
    else
    {
        ret.append( c );
    }
}
value = ret.toString();

---------------------------------------------------------

after put:

int len = value.length();
StringBuffer ret = new StringBuffer( len );
for ( int i = 0; i < len; i++ )
{
    char c = value.charAt( i );
    if ( c == '\\' )
    {
        i++;
        if ( i < len )
        {
            c = value.charAt( i );
            if ( c == 'n' )
            {
                ret.append( '\n' );
            }
            else if ( c == '\\' )
            {
                ret.append( '\\' );
            }
            else
            {
                throw new Error( "wrong format" );
            }
        }
        else
        {
            throw new Error( "wrong format" );
        }
    }
    else
    {
        ret.append( c );
    }
}
value = ret.toString();
(Review ID: 163650)
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