Sorting an XML in Java

Question

I have an XML similar to below, which needs to be sorted using the date field.

<root> 
    <Node1>
        <date></date> 
    </Node1> 
    <Node1> 
        <date></date> 
    </Node1> 
    <Node1> 
        <date></date> 
    </Node1> 
    <Node1> 
        <date></date> 
    </Node1> 
    <Node2> 
        <date></date> 
    </Node2> 
    <Node2> 
        <date></date> 
    </Node2> 
    <Node2> 
        <date></date> 
    </Node2> 
    <Node2> 
        <date></date> 
    </Node2> 
</root>

I would like to sort the XML based on the date(say ascending order), irrespective of whether the date is under Node1 or Node2. Actually, in Java code I have two separate lists, one with Node1 objects and other with Node2 objects. I can sort the list in any order separately inside java. But I need to have the dates sorted irrespective of the nodes it is appearing on the XML. What is the best approach to sort this way in Java?

Actually I am using Castor for marshaling the java objects to XML. If you know this can be done with Castor, that will be great!

Answer 1

I'd use XSLT, it has probs with sorting dates that you'll need to work round, simplest way if you can control it is to have sortable date format like yyyymmdd

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">

  <xsl:template match="root">
    <xsl:copy>
        <xsl:apply-templates>
           <xsl:sort data-type="number" select="date"/>
        </xsl:apply-templates>
    </xsl:copy>
  </xsl:template>

  <xsl:template match="*">
      <xsl:copy>
          <xsl:apply-templates/>
      </xsl:copy>
  </xsl:template>

</xsl:stylesheet>