package com.lixy.practice;


import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

/**
 * Created by Administrator on 2017/3/16.
 */
public class ListTest {

    public static void main(String... args) throws Exception {
        List<Person> personList = new ArrayList<>();
        PersonFactory<Person> factory = Person::new 
 
;
        personList.add(factory.createT("LI1", "HEN", 12));
        personList.add(factory.createT("LI2", "HEN", 56));
        personList.add(factory.createT("LI3", "HEN", 14));
        personList.add(factory.createT("LI4", "THE", 18));
        personList.add(factory.createT("LI5", "THE", 16));
        personList.add(factory.createT("LI6"
 
, "THE", 25));

        //格式化1
StringBuilder sb = new StringBuilder("[");
        for (Person person : personList) {
            if(sb.length()>1)
                sb.append(",");
            sb.append(person.getFirstName());
        }
        sb.append("]");
        System.out.println(sb.toString());
        //[LI1,LI2,LI3,LI4,LI5,LI6]
 
        //格式化2
StringBuilder sb2 = new StringBuilder("[");
        personList.stream()
                .map(Person::getFirstName)
                .forEach(firstName->{
                    if(sb2.length()>1)
                        sb2.append(",");
                    sb2.append(firstName);
                });
        sb2.append("]");
        System.out.println(sb2.toString());
        //[LI1,LI2,LI3,LI4,LI5,LI6]
        //格式化3
String result = personList.stream()
                  .map(Person::getFirstName)
                  .collect(Collectors.joining(",", "[", "]"));
        System.out.println(result);
        //[LI1,LI2,LI3,LI4,LI5,LI6]
        //按照lastName分組
Map<String, List<Person>> collect = personList.stream()
                .collect(Collectors.groupingBy(Person::getLastName));
        System.out.println(collect);
        /*{THE=[Person{firstName='LI4', lastName='THE'}, Person{firstName='LI5', lastName='THE'}, Person{firstName='LI6', lastName='THE'}],
         HEN=[Person{firstName='LI1', lastName='HEN'}, Person{firstName='LI2', lastName='HEN'}, Person{firstName='LI3', lastName='HEN'}]}*/
        //獲取lastName分組後的的所有firstName集合 簡單方式
Map<String, List<String>> nameOfListFirstName = new HashMap<>();
        for (Map.Entry<String, List<Person>> entry : collect.entrySet()) {
            nameOfListFirstName.put(entry.getKey(), entry.getValue().stream()
                    .map(Person::getFirstName)
                    .collect(Collectors.toList()));
        }
        System.out.println(nameOfListFirstName);
        //{THE=[LI4, LI5, LI6], HEN=[LI1, LI2, LI3]}
        //收集器方式 最外層groupingBy分組,接著按firstName進行統計並放入集合
Map<String, List<String>> nameOfListFirstName2 = personList.stream()
                .collect(Collectors.groupingBy(Person::getLastName,
                        Collectors.mapping(Person::getFirstName,Collectors.toList())));


        System.out.println(nameOfListFirstName2);

        //按照lastName分組並統計其數量
Map<String,Long> map = personList.stream()
                .collect(Collectors.groupingBy(Person::getLastName,Collectors.counting()));
        System.out.println(map);
        //{THE=3, HEN=3}
        //對年齡進行統計
//double格式的結果
DoubleSummaryStatistics doubleSummaryStatistics = personList.stream()
                .map(person->person.getAge()+1)
                .collect(Collectors.summarizingDouble(value -> value));
       //DoubleSummaryStatistics{count=6, sum=147.000000, min=13.000000, average=24.500000, max=57.000000}
System.out.println(doubleSummaryStatistics);
        System.out.println(doubleSummaryStatistics.getAverage());
        System.out.println(doubleSummaryStatistics.getMax());
        System.out.println(doubleSummaryStatistics.getCount());

        //int格式的結果 還有其他long等型別
IntSummaryStatistics intSummaryStatistics = personList.stream()
                .map(person -> person.getAge())
                .collect(Collectors.summarizingInt(value -> value));

        System.out.println(intSummaryStatistics);
        //IntSummaryStatistics{count=6, sum=141, min=12, average=23.500000, max=56}
        //求平均值
Double dAvg = personList.stream()
                .map(Person::getAge)
                .collect(Collectors.averagingDouble(value -> value)); //將值加一
System.out.println(dAvg);


        //根據List建立Map
List<Integer> list = IntStream.range(1, 10).boxed().collect(Collectors.toList());//生成1到9
System.out.println(list);
        //[1, 2, 3, 4, 5, 6, 7, 8, 9]
Map<Integer, Integer> _map = list.stream()
                                     .sorted((a, b) -> a.compareTo(b))
                                     .collect(Collectors.toMap(p -> p, q -> q * 3));
        System.out.println(_map);
        //{1=3, 2=6, 3=9, 4=12, 5=15, 6=18, 7=21, 8=24, 9=27}
        //求最大值
List<Integer> list2 = new Random().ints(-100,100).limit(250).boxed().collect(Collectors.toList());
        Optional<Integer> max = list.stream().reduce(Math::max);
        max.ifPresent(value -> System.out.println(value));



        //把所有的姓名大寫、排序，再輸出
String[] names = { "Fred Edwards", "Anna Cox", "Deborah Patterson", "Ruth Torres", "Shawn Powell",
                "Rose Thompson", "Rachel Barnes", "Eugene Ramirez", "Earl Flores", "Janice Reed", "Sarah Miller",
                "Patricia Kelly", "Carl Hall", "Craig Wright", "Martha Phillips", "Thomas Howard", "Steve Martinez",
                "Diana Bailey", "Kathleen Hughes", "Russell Anderson", "Theresa Perry" };
        Arrays.asList(names)
                .stream()
                .map(String::toUpperCase)
                .sorted().forEach(System.out::println);

    }
}


    //定義建立物件介面
interface PersonFactory<P extends Person> {
        P createT(String firstName, String lastName,int age);
    }