Java Map Reverse sortByValue(Map map, boolean doReverse)

Description

Sorts a map based on value, returns sorted map with predictable iteration Initial code from: http://stackoverflow.com/questions/109383/how-to-sort-a-mapkey-value-on-the-values-in-java

License

Open Source License

Parameter

Parameter	Description
map	Map with assumed-Compable values
doReverse	True if comparator's ordering should be reversed, False if normal

Declaration

public static <K, V extends Comparable<? super V>> Map<K, V> sortByValue(Map<K, V> map, boolean doReverse) 

Method Source Code

//package com.java2s;
//License from project: Open Source License 

import java.util.Collections;
import java.util.Comparator;
import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

public class Main {
    /**/*from  www .  j  a v  a2 s  .c  o m*/
     * Sorts a map based on value, returns sorted map with predictable iteration
     * Initial code from: http://stackoverflow.com/questions/109383/how-to-sort-a-mapkey-value-on-the-values-in-java
     * @param map Map with assumed-Compable values
     * @param doReverse True if comparator's ordering should be reversed, False if normal
     * @return
     */
    public static <K, V extends Comparable<? super V>> Map<K, V> sortByValue(Map<K, V> map, boolean doReverse) {
        List<Map.Entry<K, V>> list = new LinkedList<Map.Entry<K, V>>(map.entrySet());

        Comparator<Map.Entry<K, V>> comparator = 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());
            }
        };

        if (doReverse) {
            Collections.sort(list, Collections.reverseOrder(comparator));
        } else {
            Collections.sort(list, comparator);
        }

        Map<K, V> result = new LinkedHashMap<K, V>();
        for (Map.Entry<K, V> entry : list) {
            result.put(entry.getKey(), entry.getValue());
        }
        return result;
    }

    /**
     * Sorts a map based on value, returns sorted map with predictable iteration
     * Initial code from: http://stackoverflow.com/questions/109383/how-to-sort-a-mapkey-value-on-the-values-in-java
     * @param map Map with assumed-Compable values
     * @return
     */
    public static <K, V extends Comparable<? super V>> Map<K, V> sortByValue(Map<K, V> map) {
        return sortByValue(map, false);
    }
}

Related

1. reverseMapping(Map map)
2. sort(Map> dataNodes, boolean reverse)
3. sort(Map source, boolean reverse)
4. sortByUsedSpace(Map> dataNodes, boolean reverse)
5. sortByValue(Map map, boolean reverse)
6. toReverseIndex( Map> forwardIndex)