xquery to find value of a child attribute by giving values for one attibute at same level and parent and one of

Question

I need to find value for a child attribute by giving values for one attibute at the same level and its parent at highere level.
Another requirement is
find value for a child attribute for which another attribute at same level with maximum value and given value for parent at higher level

Here is my XML

`<root>
  <ACTS>
    <ACT>Play</ACT>
    <A>
      <Day>1</Day>
      <time>Fri Feb 28 13:21:42 IST 2014</time>
    </A>
    <A>
      <Day>2</Day>
      <time>Fri Feb 28 13:21:43 IST 2014</time>
    </A>    
  </ACTS>
  <ACTS>
    <ACT>Study</ACT>
    <A>
      <Day>1</Day>
      <time>Fri Feb 28 13:21:42 IST 2014</time>
    </A>
    <A>
      <Day>2</Day>
      <time>Fri Feb 28 13:21:43 IST 2014</time>
    </A> 
    <A>
      <Day>3</Day>
      <time>Fri Feb 28 13:21:43 IST 2014</time>
    </A>   
  </ACTS>
</root>
`   

and the rquirement is to find the value for time attribute by giving values as Day=3 and ACT =Study

find time where ACT =Study and Day= maximum value under ACT=Study

I have tried the same with xpath and ended up with a mess (not able to retrieve values from Nodelist).

someone please guide me xquery and its usage in java for this..

which is best in this situation xquery or xpath.

Answer 1

let $x :=

<root>
<ACTS>
<ACT>Play</ACT>
<A>
  <Day>1</Day>
  <time>Fri Feb 28 13:21:42 IST 2014</time>
</A>
<A>
  <Day>2</Day>
  <time>Fri Feb 28 13:21:43 IST 2014</time>
</A>    
</ACTS>
<ACTS>
<ACT>Study</ACT>
<A>
  <Day>1</Day>
  <time>Fri Feb 28 13:21:42 IST 2014</time>
</A>
<A>
  <Day>2</Day>
  <time>Fri Feb 28 13:21:43 IST 2014</time>
</A> 
<A>
  <Day>3</Day>
  <time>Fri Feb 28 13:21:43 IST 2014</time>
</A>   
</ACTS>
</root>

XQuery -

let $maxDay := max($x//ACTS[ACT="Study"]/A/Day)
for $y in $x//ACTS[ACT/text()="Study"]/A[Day/text()=$maxDay]/time
 return $y

XPath -

//ACTS[ACT/text()="Study"]/A[Day/text()=max(//ACTS[ACT="Study"]/A/Day)]/time

You said - "someone please guide me xquery and its usage in java for this.. "

For this please refer following posts -

1. How to read XML using XPath in Java

2. Parsing XML with XPath in Java

Assuming your Java code is right, I think, your XPath expression put you in the mess. BTW, above links would guide you for the correctness of Java code.

You asked - "which is best in this situation xquery or xpath. "

Google for "Difference between XQuery and XPath", and you will get the answer.

HTH :)