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

[Aleksej Efimov]

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
>