Java comparator for multi-column sorting?

Question

Is there any Java open-source comparator for comparing beans by multiple fields for multi-column sorting? Each column can be sorted asceding or descending.

For singl

Answer 1

I recently wrote a Comparator to sort multiple fields within a delimited String record. It allows you to define the delimiter, record structure and sorting rules (some of which are type-specific).

Required information is seeded to the Comparator itself, either programmatically or through an XML file.

XML is validated by a package embedded XSD file. For example, below is a tab delimited record layout with four fields (two of which are sortable):

 


    	

    
        Column One
    

    
        Column Two
    

    
        Column Three
        2
        true
        false        
        true
    

    
        Column Four
        1
        true
        true
        true
        yyyy-MM-dd
    

You would then use this in java like so:

Comparator comparator = new RowComparator(
              new XMLStructureReader(new File("layout.xml")));

Library can be found here:

http://sourceforge.net/projects/multicolumnrowcomparator/