[jdom-interest] Bug in Element.getChildren().listIterator(pos)

[Paul Cantrell]

Working on Macker (at http://innig.net/macker if you're curious), I 
found a bug in the listIterator(int) method of the list returned by 
Element.getChildren().

The following code demonstrates the bug -- it incorrectly generates a 
ClassCastException if element contains text content after its last 
child element:

         List children = element.getChildren();
         for(ListIterator childIter = 
children.listIterator(children.size()); childIter.hasPrevious(); )
             {
             Element subElem = (Element) childIter.previous();
	.......
             }

The exception occurs because the call to childIter.previous() 
erroneously returns a Text object the first time it is called.

The problem appears to be in the last line 
ContentList.java.initializeCursor(int start), which is 
ContentList.java:1277 in the nightly I just picked up.  The final 
return incorrectly presumes that the last element in the list matches 
the filter.  The method *should* go something like this:

         private int initializeCursor(int start) {
             if (start < 0) {
                 throw new IndexOutOfBoundsException("Index: " + start);
             }

             int count = 0;
             int lastMatchPos = -1;  // <---------
             for (int i = 0; i < ContentList.this.size(); i++) {
                 Object obj = ContentList.this.get(i);
                 if (filter.matches(obj)) {
                     lastMatchPos = i;  // <----------
                     if (start == count) {
                         return i;
                     }
                     count++;
                 }
             }

             if (start > count) {
                 throw new IndexOutOfBoundsException("Index: " + start +
                                                     " Size: " + count);
             }

             return lastMatchPos + 1; // <---------
         }

WARNING: I haven't tested this patch -- I just typed it straight into 
the email.  (Sorry!)  I hope it's not too far off the mark.

Cheers,

Paul