RFR 8024707: TRANSFORMEREXCEPTION : ITEM() RETURNS NULL WITH NODE LIST OF LENGTH =1 IN JAXP

[huizhe wang]

Hi Aleksej,

 From your tests, it appears that the getLength() method was implemented 
correctly, and that the bug is not in the call to m_iter.next(), but it 
should not be called again once the count is > index.  So that fix would 
be to move the conditions around such that:
     public Node item(int index) {
         if (m_iter != null) {
             int node;
             int count = m_cachedNodes.size();

             if (count > index) {
                 node = m_cachedNodes.elementAt(index);
                 return m_dtm.getNode(node);
             } else if (m_last == -1) {
-                while (((node = m_iter.next()) != DTMAxisIterator.END)
-                           && count <= index) {
+                while (count <= index
+                           && ((node = m_iter.next()) != 
DTMAxisIterator.END)) {
                     m_cachedNodes.addElement(node);
                     count++;
                 }
                 if (node == DTMAxisIterator.END) {
                     m_last = count;
                 } else {
                     return m_dtm.getNode(node);
                 }
             }
         }
         return null;
     }

Thanks,
Joe


On 9/25/2013 4:10 AM, Aleksej Efimov wrote:
> Hi Joe,
> Your suggestion about getLength() brings to mine attention the 
> following behavior of unmodified JDK:
> If we slightly modify a TestFunc class [1] in such manner:
>
>     public static Node test( NodeList list ) {
>                  Node ret = list.item(0);
>                  System.err.println(list.getLength());
>                  return ret;
>     }
>
> And add more elements to in.xml:
> <input1><seq-elem1>inp1_1</seq-elem1><seq-elem1>inp1_2</seq-elem1><seq-elem1>inp1_3</seq-elem1></input1>
>
> The test will fails:
>
>     2
>     Transformation completed. Result:<?xml version="1.0"
>     encoding="UTF-8"?>inp1_2
>     Exception in thread "main" java.lang.RuntimeException: Incorrect
>     transformation result
>         at XSLT.main(XSLT.java:49)
>
> As you can see the length of 2 is incorrect value and the 'inp1_1' 
> element is ignored. But If we do another one change to test function - 
> first get the length() and then get the item:
>
>     public static Node test( NodeList list ) {
>     	    System.err.println(list.getLength());
>                  Node ret = list.item(0);
>                  return ret;
>     }
>
> The test will pass:
>
>     3
>     Transformation completed. Result:<?xml version="1.0"
>     encoding="UTF-8"?>inp1_1
>
> This behavior tells that item() method incorrectly caches the nodes 
> (The method called first - do the caching). But the caching of nodes 
> is done in correct way by getLength() function, but its according to 
> the test results. Currently, I'm trying to understand why it's working 
> in such way in a view of source code.
>
> -Aleksej
>
>
>
> [1] 
> http://cr.openjdk.java.net/~aefimov/8024707/jdk/test/javax/xml/jaxp/parsers/8024707/TestFunc.java 
> <http://cr.openjdk.java.net/%7Eaefimov/8024707/jdk/test/javax/xml/jaxp/parsers/8024707/TestFunc.java>
>
> On 09/20/2013 01:19 AM, huizhe wang wrote:
>> Hi Aleksej,
>>
>> Looks like the getLength() method has the same problem.
>>
>> Joe
>>
>> On 9/17/2013 5:01 AM, Aleksej Efimov wrote:
>>> Hi Everyone,
>>>
>>> There is a bug [1] in JAXP about transformation of one-item sized 
>>> node list:
>>> When the length of nodelist which is passed to a XSLT extension 
>>> function is 1, the node gotten from the node list becomes null.
>>> New test illustrates this issue [2]. Full webrev with proposed fix 
>>> can be found here: [3].
>>>
>>> [1] http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8024707
>>> [2] 
>>> http://cr.openjdk.java.net/~aefimov/8024707/raw_files/new/jdk/test/javax/xml/jaxp/parsers/8024707/XSLT.java
>>> [3] http://cr.openjdk.java.net/~aefimov/8024707/
>>>
>>> Best regards,
>>> Aleksej
>>
>