Main.java Source code

Introduction

Here is the source code for Main.java

Source

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 {
    public static void main(String[] args) {
        SortableValueMap<String, Double> map = new SortableValueMap<String, Double>();

        map.put("A", 6.5);
        map.put("B", 9.5);
        map.put("C", 8.4);
        map.put("D", 4.0);

        print("Unsorted map", map);
        map.sortByValue();
        print("Sorted map", map);
    }

    private static void print(String text, Map<String, Double> map) {
        System.out.println(text);

        for (String key : map.keySet()) {
            System.out.println("key/value: " + key + "/" + map.get(key));
        }
    }
}

class SortableValueMap<K, V extends Comparable<V>> extends LinkedHashMap<K, V> {
    public SortableValueMap() {
    }

    public SortableValueMap(Map<K, V> map) {
        super(map);
    }

    public void sortByValue() {
        List<Map.Entry<K, V>> list = new LinkedList<Map.Entry<K, V>>(entrySet());

        Collections.sort(list, new Comparator<Map.Entry<K, V>>() {
            public int compare(Map.Entry<K, V> entry1, Map.Entry<K, V> entry2) {
                return entry1.getValue().compareTo(entry2.getValue());
            }
        });

        clear();

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