[jira] [Updated] (DERBY-2106) Improve Derby SQL/XML processing to account for Xalan's use of platform-specific newlines when serializing.

["Mamta A. Satoor (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/DERBY-2106?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Mamta A. Satoor updated DERBY-2106:
-----------------------------------

    Urgency: Low
     Labels: derby_triage10_11  (was: )
    
> Improve Derby SQL/XML processing to account for Xalan's use of platform-specific newlines when serializing.
> -----------------------------------------------------------------------------------------------------------
>
>                 Key: DERBY-2106
>                 URL: https://issues.apache.org/jira/browse/DERBY-2106
>             Project: Derby
>          Issue Type: Improvement
>          Components: SQL
>    Affects Versions: 10.2.1.6, 10.2.2.0, 10.3.1.4
>            Reporter: A B
>            Priority: Minor
>              Labels: derby_triage10_11
>
> Derby uses Apache Xalan to serialize XML data values.  As part of the serialization process Xalan converts the newline character ("\n") to a platform-specific line ending.  This conversion of line endings is allowed by XML serialization rules and therefore is not a bug in Xalan--see XALANJ-1137 for some discussion along those lines.  That said, though, this particular behavior means that an application which uses Derby to serialize XML values can end up with different characters on different platforms.  And further, since Derby currently writes serialized XML to disk, this means that insertion of an XML value on one platform (such as Windows) can lead to different line-ending characters on disk than insertion of that exact same XML value on another platform (such as Linux).
> Discussion on the derby-dev list seems to indicate (based on lack of comments to the contrary) that this behavior in Derby is not a "bug" per se, but that it might be nice if Derby could somehow account for Xalan's treatment of newlines to provide consistent XML serialization results across platforms.  The relevant thread is here:
>   http://thread.gmane.org/gmane.comp.apache.db.derby.devel/33170/focus=33170 
> As indicated in that thread, one simple (but not fully tested) approach is to make a change in the "serializeToString()" method of SqlXmlUtil.java to do an explicit replacement of platform-specific line-endings with a simple newline.  Something like:
> +        String eol = PropertyUtil.getSystemProperty("line.separator");
> +        if (eol != null)
> +            return sWriter.toString().replaceAll(eol, "\n");
>         return sWriter.toString();
> This small change seems to provide consistent results across all platforms, and appears to work correctly even if line-endings are hard-coded in the XML file (ex. if the literal "\r\n" occurs in the XML file, the above code will *not* replace it, which is good).  However, internal modification of user-supplied data is generally a risky proposal, so more testing would be needed for this particular approach.
> Also, any changes to Derby serialization as a part of this issue would need to consider backward-compatibility issues--namely, how would the changes affect XML files that have already been inserted into the database (and therefore that already have platform-specific endings)?  Ideally treatment of existing and new XML data would be consistent.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira