Testing apache-commons ComparatorChain

gistfile1.groovy

//Quick test to check the ComparatorChain in the apache-commons libraries.

@Grab(group='commons-collections', module='commons-collections', version='3.0')
@Grab(group='commons-beanutils', module='commons-beanutils', version='1.8.3')

import org.apache.commons.beanutils.BeanComparator
import org.apache.commons.collections.comparators.ComparatorChain
import org.apache.commons.collections.comparators.NullComparator

class Test {
    
    static class SortThing implements Comparable {
        String first
        String last
        
        //ComparatorChain requires collection of comparable objects
        public int compareTo(Object o) {
            return toString().compareTo(o == null ? "null" : o.toString())
        }
        
        public String toString() {
            return "[${last}, ${first}]"
        }
    }
    
    static void main(String[] args) {
        def desc = false
        
        List<SortThing> thingsToSort = [
            new SortThing([last: 'A', first: '3']), new SortThing([last: 'D', first: '1']), new SortThing([last: 'B', first: '2']),
            new SortThing(),
            new SortThing([last: 'C', first: '5']), new SortThing([last: 'C', first: '7']), new SortThing([last: 'C', first: '6'])
        ] as LinkedList<SortThing>
        
        ComparatorChain chain = new ComparatorChain()
        chain.addComparator(new BeanComparator("last", new NullComparator()))
        chain.addComparator(new BeanComparator("first"))
        
        Collections.sort(thingsToSort, chain)
        println thingsToSort
        
        chain = new ComparatorChain()
        chain.addComparator(new BeanComparator("first", new NullComparator()))
        chain.addComparator(new BeanComparator("last"))
        
        Collections.sort(thingsToSort, chain)
        println thingsToSort
    }
}