基于地图值和比较器的Java地图分类方法

Posted 2021-02-26

 
	/**
	 * A helper method that sorts the map sent, based on sorting its values 
	 * using the comparator passed with it
	 * 
	 * @param input The map to be sorted
	 * @param comparator the comparator to be used to sort the map values
	 * 
	 * @return A new Sorted HashMap that holds the values 
	 * 
	 * @author DKasem
	 * @since Feb 15, 2010
	 * @version 0.4.2
	 */
	public static <T,E> Map<T, E> sortMap(final Map<T, E> input,Comparator<E> comparator){
	    Map<T, E> tempMap = new HashMap<T, E>();
	    for (T wsState : input.keySet()){
	        tempMap.put(wsState,input.get(wsState));
	    }
 
	    List<T> mapKeys = new ArrayList<T>(tempMap.keySet());
	    List<E> mapValues = new ArrayList<E>(tempMap.values());
 
	    // Resultant map
	    HashMap<T, E> sortedMap = new LinkedHashMap<T, E>();
 
	    List<E> sortedList = new ArrayList<E>(mapValues);
	    Collections.sort(sortedList,comparator);
	    for (int i=0; i<sortedList.size(); i++){
	        sortedMap.put(mapKeys.get(mapValues.indexOf(sortedList.get(i))),(E)sortedList.get(i));
	    }
	    return sortedMap;
	}