public class TreeUtil {

    /**
     * List轉(zhuǎn)Tree
     * @param source 源數(shù)據(jù)(List)
     * @param resultList 結(jié)果數(shù)據(jù)(Tree)
     * @param root 是頂級菜單的條件
     * @param getIdFunction 獲取id
     * @param getPIdFunction 獲取父id
     * @param getChildFunction 獲取子列表
     * @param setChildFunction 設(shè)置子列表
     * @param <T> 類型
     * @return 結(jié)果數(shù)據(jù)(Tree)
     */
    public static <T> List<T> list2Tree(List<T> source,List<T> resultList, Predicate<T> root, Function<T,?> getIdFunction, Function<T,?> getPIdFunction, Function<T,List<T>> getChildFunction, BiConsumer<T,List<T>> setChildFunction){
        //<id,實(shí)體>
        final Map<Object,T> map = new HashMap<>();
        //遍歷處理
        source.forEach((it)->{
            Optional.ofNullable(root).map(r -> {
                if (r.test(it)){
                    resultList.add(it);
                }
                return it;
            }).orElseGet(() -> {
                Optional.ofNullable(getPIdFunction.apply(it)).orElseGet(() -> {
                    resultList.add(it);
                    return null;
                });
                return null;
            });
            map.put(getIdFunction.apply(it),it);
        });
        //遍歷處理
        source.forEach((it)->{
            map.computeIfPresent(getPIdFunction.apply(it), (k, v)->{
                Optional.ofNullable(getChildFunction.apply(v)).orElseGet(()->{
                    final List<T> list = new ArrayList<>();
                    setChildFunction.accept(v,list);
                    return list;
                }).add(it);
                return v;
            });
        });
        return resultList;
    }

    /**
     * Tree轉(zhuǎn)List
     * @param source 源數(shù)據(jù)(Tree)
     * @param resultList 結(jié)果數(shù)據(jù)(List)
     * @param getChildFunction 獲取子列表
     * @param setChildFunction 設(shè)置子列表
     * @param <T> 類型
     * @return 結(jié)果數(shù)據(jù)(List)
     */
    public static <T> List<T> tree2List(List<T> source,List<T> resultList,Function<T,List<T>> getChildFunction,BiConsumer<T,List<T>> setChildFunction){
        source.forEach((it) -> {
            List<T> childList = getChildFunction.apply(it);
            if (null != childList && 0 != childList.size()){
                tree2List(childList,resultList,getChildFunction,setChildFunction);
            }
            setChildFunction.accept(it,null);
            resultList.add(it);
        });
        return resultList;
    }

    /**
     * 在樹上獲取分支
     * @param source 源數(shù)據(jù)(Tree)
     * @param resultList 結(jié)果數(shù)據(jù)(List)
     * @param root 分支的條件
     * @param <T> 類型
     * @return 結(jié)果數(shù)據(jù)(List)
     */
    public static <T> List<T> getBranchFromTree(List<T> source,List<T> resultList,Predicate<T> root,Function<T,List<T>> getChildFunction,BiConsumer<T,List<T>> setChildFunction){
        if (null == source || 0 == source.size()){
            return source;
        }
        source.forEach((it)->{
            List<T> childList = getChildFunction.apply(it);
            if (!root.test(it)){
                getBranchFromTree(childList,resultList,root,getChildFunction,setChildFunction);
            }else {
                if (null != childList && 0 != childList.size()){
                    getBranchFromTree(childList,resultList,t -> { return true; },getChildFunction,setChildFunction);
                }
                setChildFunction.accept(it,null);
                resultList.add(it);
            }
        });
        return resultList;
    }
}