DO NOT REPLY [Bug 15466] New: - XNodeSet.getStringFromNode() gives NullPointerException

[bugzilla]

DO NOT REPLY TO THIS EMAIL, BUT PLEASE POST YOUR BUG 
RELATED COMMENTS THROUGH THE WEB INTERFACE AVAILABLE AT
<http://nagoya.apache.org/bugzilla/show_bug.cgi?id=15466>.
ANY REPLY MADE TO THIS MESSAGE WILL NOT BE COLLECTED AND 
INSERTED IN THE BUG DATABASE.

http://nagoya.apache.org/bugzilla/show_bug.cgi?id=15466

XNodeSet.getStringFromNode() gives NullPointerException

           Summary: XNodeSet.getStringFromNode() gives NullPointerException
           Product: XalanJ2
           Version: 2.4
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: Normal
          Priority: Other
         Component: org.apache.xpath
        AssignedTo: [EMAIL PROTECTED]
        ReportedBy: [EMAIL PROTECTED]


In XNodeSet.getStringFromNode() there is the following code:

  public XMLString getStringFromNode(int n)
  {
    // %OPT%
    // I guess we'll have to get a static instance of the DTM manager...
    if(DTM.NULL != n)
    {
      return m_dtmMgr.getDTM(n).getStringValue(n);
    }
    else
    {
      return org.apache.xpath.objects.XString.EMPTYSTRING;
    }
  }

The comment indicates awareness that if m_dtmMgr is null there will be a 
problem. Some other methods also contain similar code. Some XNodeSet 
instantiations will result in the m_dtmMgr not being set. My initial thought 
was to use getDTMManager() on the iterator in the constructor to set the 
m_dtmMgr, this fixed some cases, but broke others (I was not able to figure out 
why). I then implemented a change in getStringFromNode(), getNumberFromNode(), 
and dispatchCharactersEvents() that seems to work in all cases that I tested. 
This change is similar to the following example with getStringFromNode():

  public XMLString getStringFromNode(int n)
  {
    // %OPT%
    // I guess we'll have to get a static instance of the DTM manager...
    if(DTM.NULL != n)
    {
      if ( m_dtmMgr != null )
        return m_dtmMgr.getDTM(n).getStringValue(n);
          else
        return m_iter.getDTMManager().getDTM(n).getStringValue(n);
    }
    else
    {
      return org.apache.xpath.objects.XString.EMPTYSTRING;
    }
  }

Basically if m_dtmMgr is not set then use m_iter.getDTMManager() to get the DTM 
manager. As I said, in my testing this works. My only concerns are that the 
comment indicates an awareness of the issue - but this simple change had not 
been made, and that perhaps a better solution is/was in the works.