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package com.ideaaedi.commonds.rank;


import com.ideaaedi.commonds.sort.DefaultSortSupporter;
import com.ideaaedi.commonds.sort.SortStrategy;
import com.ideaaedi.commonds.sort.SortSupporter;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

/**
 * 排名器
 * 

 * P.S. 这是稳定的
 *
 * @author JustryDeng 
 * @since 1.0.0
 */
public class Ranker> {
    
    private final SortSupporter sortSupporter;
    
    private final RankSupporter rankSupporter;
    
    private Ranker(SortSupporter sortSupporter, DefaultRankSupporter rankSupporter) {
        this.sortSupporter = sortSupporter;
        this.rankSupporter = rankSupporter;
    }
    
    public static > Ranker defaultInstance(){
        return new Ranker<>(new DefaultSortSupporter(), new DefaultRankSupporter());
    }
    
    
    public static > Ranker buildInstance(SortSupporter sortSupporter, DefaultRankSupporter rankSupporter){
        return new Ranker<>(new DefaultSortSupporter(), new DefaultRankSupporter());
    }
    
    /**
     * @see Ranker#generateRankingList(Collection, boolean, SortStrategy, RankStrategy)
     */
    public List generateRankingList(Collection dataList, boolean asc) {
        return this.generateRankingList(dataList, asc, SortStrategy.AUTO, RankStrategy.INDEX_POSTPONED_IF_SAME);
    }
    
    /**
     * 排序
     *
     * @param dataList
     *         要被排名的数据集
     * @param asc
     *            true-正向， false-反向
     * @param sortStrategy
     *         排序策略
     * @param rankStrategy
     *         排名策略
     *
     * @return 排序后的数据
     */
    public List generateRankingList(Collection dataList, boolean asc, SortStrategy sortStrategy, RankStrategy rankStrategy) {
        // -> 数据整理
        if (dataList == null || dataList.size() == 0) {
            return new ArrayList<>();
        }
        List nullList = new ArrayList<>(16);
        List nonNullList = new ArrayList<>(16);
        dataList.forEach(x -> {
                    if (x == null) {
                        nullList.add(null);
                    } else {
                        nonNullList.add(x);
                    }
                }
        );
        if (nonNullList.size() == 0) {
            return nullList;
        }
        // -> 排序
        List nonNullSortedList = sortSupporter.doSort(nonNullList, sortStrategy, asc);
        // -> 排名
        List sortedAndRankedList = rankSupporter.doRank(nonNullSortedList, rankStrategy);
        // 将null元素， 放置在最后
        sortedAndRankedList.addAll(nullList);
        return sortedAndRankedList;
    }
    
}