MapUtil.java

package common;

import java.util.*;

public class MapUtil
{
    public static <K, V extends Comparable<? super V>> Map<K, V> sortByValue( Map<K, V> map )
    {
        List<Map.Entry<K, V>> list =
            new LinkedList<Map.Entry<K, V>>( map.entrySet() );
        Collections.sort( list, new Comparator<Map.Entry<K, V>>()
        {
            public int compare( Map.Entry<K, V> o1, Map.Entry<K, V> o2 )
            {
                return -(o1.getValue()).compareTo( o2.getValue() );
            }
        } );

        Map<K, V> result = new LinkedHashMap<K, V>();
        for (Map.Entry<K, V> entry : list)
        {
            result.put( entry.getKey(), entry.getValue() );
        }
        return result;
    }
    
    public static void normalizeMap(Map<Integer, Double> map) {
    	double denom = 0.0;
		for (Map.Entry<Integer, Double> e : map.entrySet()) {
			denom += Math.exp(e.getValue());
		}
		for (Map.Entry<Integer, Double> e : map.entrySet()) {
			e.setValue(Math.exp(e.getValue()) / denom);
		}
    }
}